Doc #47 — Adhesives and Sealants from NZ Materials

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RECOMMENDED ACTIONS

Phase 1 — First months (Months 0–6)

1. Include adhesives and sealants in the national consumable inventory (Doc #1, Doc #8). Count wholesale warehouse stocks, retail stocks (hardware stores, trade suppliers), and industrial stocks at building firms, joinery workshops, boatbuilders, and manufacturers. Classify by type: wood glue (PVA), epoxy, construction adhesive, silicone sealant, contact cement, hot-melt, cyanoacrylate, and specialty adhesives. This is not urgent — adhesive stocks are not being consumed at crisis rates — but should be included in the standard Category A requisition inventory.

2. Allocate epoxy resin as a strategic reserve. Epoxy cannot be locally produced and is irreplaceable for structural bonding, marine applications, and composite repair. All wholesale and retail epoxy stocks should be centrally managed and allocated only for applications where no alternative exists. Urgency: moderate — epoxy stocks are not large but depletion under reduced consumption is slow. Can be implemented as part of the broader industrial consumable sweep (Doc #7), not as a standalone action.

3. Begin hide glue production at rendering plants. NZ rendering facilities (Wallace Corporation, Silver Fern Farms, ANZCO Foods, Alliance Group, Talleys) already process animal hides, bones, and connective tissue — the raw materials for hide glue. Co-locating glue production with rendering is efficient. Production can begin within weeks using existing equipment (heating vessels, filtration, drying capacity). Urgency: low — commercial PVA and other adhesives will remain available for months. Begin production to build capability and establish quality, not to meet immediate demand.

4. Begin casein glue development at dairy processing sites. NZ’s dairy industry produces casein commercially — primarily for export as a food ingredient and industrial feedstock. Existing casein powder stocks and production capability can be redirected to adhesive production. Fonterra, Westland Milk Products, and Open Country Dairy all have relevant infrastructure.³ Urgency: low — development and testing, not emergency production.

5. Allocate synthetic adhesives by application criticality. Epoxy and silicone sealant should be reserved for applications where no natural alternative exists (marine structural bonding, metal bonding, waterproof sealing). PVA and construction adhesives can be replaced by hide glue and casein as local production develops. Woodworkers and builders will naturally conserve adhesive once supply is visibly constrained — the allocation system ensures irreplaceable products go to the highest-value uses.

Phase 1–2 — Months 6–18

6. Establish pine pitch collection from radiata pine forestry operations. Coordinate with forestry crews (Doc #102) to collect resin from standing trees by tapping or from stumps and slash. Pine pitch production can be co-located with charcoal production (Doc #102) — both involve thermal processing of pine wood, and pitch is a natural byproduct of charcoal retort kilns.

7. Scale hide glue production to regional supply. Establish quality grading and distribute production guidance to smaller community-level rendering operations.

8. Test casein glue formulations for plywood production. If NZ is to produce plywood (a critical structural material), casein-bonded plywood is the most feasible route. This requires systematic testing of casein glue formulations — lime-casein, sodium hydroxide-casein — for bond strength, water resistance, and durability. Partner with remaining NZ plywood manufacturers (if operational) for production trials.

9. Develop beeswax and tallow-based sealants. Establish formulations and production for caulking, waterproofing, and general sealing applications. Coordinate with beekeeping operations (Doc #83) and rendering plants (Doc #34).

Phase 2–3 — Years 1–7

10. Transition all non-critical adhesive applications to natural glues. Woodworking, furniture, bookbinding, paper products, and general workshop bonding should use hide glue or casein glue as standard.

11. Develop blood albumin glue for plywood. Blood albumin — protein extracted from slaughter blood — was historically used for water-resistant plywood and has potential as an NZ-producible adhesive. Requires development and testing.

12. Establish pitch and tar production as a routine byproduct of charcoal operations (Doc #102). Every charcoal retort should be capturing condensate for pitch, tar, and pyroligneous acid recovery.

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ECONOMIC JUSTIFICATION

Labour requirements

Adhesive production is not labour-intensive relative to other local manufactures. Each adhesive type has modest requirements:

Hide glue: Production is integrated with existing rendering operations. The incremental labour to divert collagen-rich material to glue production rather than standard rendering is approximately 0.5–1.5 person-days per week per rendering plant to produce 50–200 kg of dry hide glue — enough to supply the woodworking and general bonding needs of a substantial district.⁴

Casein glue: Casein powder production is an existing NZ dairy industry capability. Converting casein powder to adhesive requires mixing with lime or alkali at the point of use — the end user prepares the glue. The production overhead is incorporated into existing dairy processing labour with minimal additional effort.

Pine pitch: Collected as a byproduct of charcoal production (Doc #102) and forestry operations (Doc #102). The incremental labour is collection and processing of resin — approximately 0.5–1 person-day per 10–20 kg of refined pitch.

Beeswax sealants: Beeswax is a byproduct of honey production (Doc #83). Sealant formulation (melting and blending with tallow, pitch, or other components) is a few hours’ work per batch.

Total estimated labour (national production, steady state): 10–30 full-time equivalents (FTE) for production across all adhesive types. Supporting roles — forestry workers tapping pine resin, dairy workers managing casein diversion, rendering plant operators — draw on workforce already employed in those sectors. Dedicated adhesive production staff number only a fraction of total: perhaps 3–8 chemists and quality-control workers to maintain formulation standards, oversee production at multiple sites, and troubleshoot application failures.

Local production vs. rationing imported stocks

The alternative to local production is strict rationing of imported synthetic stocks until they are exhausted. The comparison favours investment in local production on the following grounds:

• Imported stocks are finite and irreplaceable. PVA, epoxy, and silicone sealant cannot be restocked once depleted. Local hide glue and casein glue production, once established, continues indefinitely from renewable domestic feedstocks.
• Import rationing is labour-costly in a different way. A rationing regime requires administration, enforcement, and allocation — a bureaucratic overhead that produces no material. Local production replaces the administrative burden with productive manufacturing work.
• Natural adhesives are adequate for the majority of applications. Section 7 documents the gaps; but 60–80% of pre-event adhesive volume by application area can be met with local alternatives. The remaining 20–40% (epoxy, silicone, contact cement) should be covered by rationed imports for as long as possible while being phased out of non-critical uses.⁵

Breakeven timeline

The question of when it makes sense to invest in local production rather than drawing down imported stocks depends on setup costs and demand:

• Hide glue: Negligible capital investment — uses existing rendering equipment. Setup time: weeks to months. Production begins generating usable output almost immediately. Breakeven against rationed PVA stocks occurs within the first year as PVA stocks deplete and demand continues.
• Casein glue: Also uses existing dairy infrastructure. Formulation testing for plywood (Phase 1–2, months 6–18) adds some lead time, but general-purpose casein adhesive can be produced and used at once from existing casein powder stocks.
• Pine pitch: Requires retort kilns with byproduct capture, which should be built anyway for charcoal production (Doc #102). Incremental investment for pitch capture is minimal — a condensation pipe and collection vessel. Pitch production begins as soon as charcoal retorts are operational (Phase 1–2).
• Pine resin tapping: The most capital-light but most labour-intensive option. No special equipment needed. Break-even depends on the demand for rosin and turpentine as inputs to varnish, soldering flux, and paper sizing — not just adhesive. Worth initiating as a small-scale trial in Phase 1–2.

Net assessment: the investment required to establish local adhesive production is low relative to many other recovery priorities. The appropriate decision is to begin local production immediately — not to wait for imported stocks to reach a critical threshold.

Opportunity cost

The 10–30 FTE employed in adhesive and sealant production must be weighed against alternative uses of that labour. At a national workforce of several million, 10–30 FTE is not a meaningful opportunity cost argument — the binding constraint on adhesive production is not skilled labour but rather institutional priority and process knowledge. The genuine opportunity cost question is at the level of facility use (competing claims on rendering plants, dairy processing time, charcoal retort capacity) rather than labour.

• Rendering plant time: Hide glue production competes with leather (Doc #101), bone meal fertiliser, and tallow production (Doc #34) for rendering capacity. Priority should be set explicitly by recovery coordinators, with adhesive production allocated a defined portion of rendering throughput. Given the small incremental requirement, this is unlikely to displace other priorities materially.
• Dairy processing time: Casein diversion competes with food protein supply. As noted above, the adhesive demand is a small fraction of total casein output. Allocation is justifiable but should be made explicit.
• Charcoal retort capacity: Pitch capture is essentially free — it is a byproduct of charcoal production, not a competing use of kiln time. No meaningful opportunity cost applies.

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1. NZ’S CURRENT ADHESIVE AND SEALANT STOCK

1.1 Import dependence

NZ imports adhesives and sealants as finished products and, to a limited degree, as raw chemical inputs. Based on NZ trade data, the total adhesive and sealant market is approximately NZ$200–400 million per year at retail value, though the volume in tonnes is more relevant for depletion analysis.⁶ Major product categories:

Category	Typical products	NZ annual consumption (estimated)	NZ substitute available?
Wood glue (PVA)	Titebond, Selleys Aquadhere	Several hundred tonnes	Yes — hide glue, casein
Epoxy resin	West System, Selleys Araldite	Tens to low hundreds of tonnes	No
Construction adhesive	Selleys Liquid Nails, Sika	Hundreds of tonnes	Partial — pitch, lime mortar
Silicone sealant	Selleys, Sika, Dow	Hundreds of tonnes	No — beeswax/pitch partial substitute
Contact cement	Ados, Bostik	Tens of tonnes	No
Hot-melt adhesive	Industrial packaging	Unknown, likely hundreds of tonnes	Partial — hide glue (reversible)
Cyanoacrylate (superglue)	Selleys, Loctite	Small volume	No
Tape (adhesive tape, duct tape)	3M, various	Significant volume	No — cloth + pitch partial substitute

Consumption estimates are rough and should be verified through distributor and trade data during the national inventory.

1.2 In-country stocks and depletion

NZ holds adhesive stocks across distributor warehouses (Sika, Henkel/Selleys, Bostik, 3M NZ), retail outlets (Bunnings, Mitre 10, PlaceMakers), trade and industrial stocks (building firms, joinery shops, boatbuilders), and institutional stores. As a rough estimate, the distribution chain holds 2–6 months of normal consumption across all categories — though this is uncertain and should be established through the national inventory.

Post-event adhesive consumption will drop to perhaps 10–30% of pre-event levels.⁷ Most adhesive use is driven by new construction, renovation, and packaging — all of which contract sharply. Continuing demands concentrate in repair and maintenance, boatbuilding (Doc #141), printing and bookbinding (Doc #29), and sealing/waterproofing. At reduced consumption, in-country stocks of most adhesive types could last 1–3 years. Specialty products (epoxy, silicone) are scarcer in stock and harder to substitute — their effective life depends heavily on allocation discipline.

1.3 Urgency assessment

Adhesive supply is not an acute crisis. Unlike fuel (days), pharmaceuticals (weeks to months), or tires (an irreplaceable constraint), adhesives are consumed slowly and natural alternatives can be produced within months. The correct Phase 1 actions are inventory, strategic allocation of irreplaceable products (particularly epoxy and silicone), and early development of natural adhesive production capability — not emergency requisition.

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2. HIDE GLUE

2.1 What hide glue is

Hide glue is a protein-based adhesive made from collagen — the structural protein found in animal skin, connective tissue, tendons, and bones. When collagen is heated in water, it denatures and dissolves, forming a viscous solution that sets to a hard, rigid bond as it cools and dries. This is the same chemistry as gelatin (food-grade gelatin is essentially purified hide glue).⁸

Hide glue was the dominant adhesive for woodworking, bookbinding, and general bonding from antiquity until the mid-20th century, when synthetic adhesives displaced it. It remains in active use for musical instrument construction, antique furniture restoration, and fine woodworking, where its specific properties — reversibility, excellent wood-to-wood bond strength, and lack of creep under sustained load — are valued.⁹

2.2 NZ raw materials

NZ’s meat processing industry provides abundant collagen-rich material:

• Hides: NZ processes approximately 3.5–4 million cattle hides and 15–20 million sheepskins per year.¹⁰ Under normal conditions, these are exported for leather production. Under recovery conditions, hides are available for both leather (Doc #101) and glue production. The two uses are not entirely in competition — hide glue can be made from hide trimmings, scrap, and material unsuitable for leather, as well as from dedicated hides.
• Bones and connective tissue: Rendering plants process large volumes of bone, tendon, and connective tissue. Bone glue (a subset of hide glue) is produced by cooking crushed bones — a process that can be integrated with existing bone meal production at rendering facilities.
• Feet, ears, and offal trimmings: High in collagen, these materials are ideal glue feedstock and have limited competing uses under recovery conditions.

Supply adequacy: NZ’s collagen-rich animal byproducts far exceed any plausible adhesive demand. Even with reduced livestock numbers under nuclear winter (Doc #76 estimates 30–50% stocking rate reductions), the available feedstock is tens of thousands of tonnes — orders of magnitude more than needed for national adhesive production.

2.3 Production process

Dependency chain: - Animal hides, bones, or connective tissue (from NZ meat processing — available) - Water (available) - Lime — calcium hydroxide, for hide preparation (from NZ limestone — Doc #97) - Heating vessel — steel or cast iron (NZ-fabricable — Doc #93, Doc #93) - Heat source — electricity or wood fire - Drying capacity — racks, moulds, or heated drying room

Step-by-step:

1. Preparation: If using hides, soak in lime water (calcium hydroxide solution) for 1–4 weeks to remove hair, fat, and non-collagen proteins. This is the same liming process used in leather tanning (Doc #101). Rinse thoroughly. If using bones, crush and degrease by boiling and skimming fat.

2. Extraction: Place prepared material in water and heat to 60–80°C (below boiling — boiling degrades the protein and weakens the final glue). Maintain temperature for 6–24 hours. The collagen dissolves into the water, forming a viscous solution. Multiple extractions from the same batch of material are possible — the first extraction produces the strongest glue, subsequent extractions produce weaker grades.¹¹

3. Filtering: Strain the liquid through cloth to remove solid particles.

4. Concentration: Evaporate excess water by gentle heating. The solution should be concentrated to a thick, syrupy consistency. Over-heating degrades the protein — temperatures above 70–80°C should be avoided during concentration. Vacuum evaporation (if available) produces higher quality by allowing concentration at lower temperatures.

5. Drying: Pour the concentrated solution into moulds or onto flat surfaces to cool and set into a semi-rigid gel. Cut into blocks or sheets and air-dry at moderate temperature (30–50°C) until hard and brittle. Well-dried hide glue is shelf-stable for years when kept dry.¹²

6. Use: To prepare for use, break dried glue into small pieces, soak in cold water for several hours until swollen, then heat gently (55–65°C) in a double boiler (glue pot). Apply hot to the joint surfaces and clamp immediately — hide glue sets as it cools, with full strength developing as the water evaporates over 24–48 hours.

2.4 Performance characteristics

Property	Hide glue	PVA (Titebond)	Epoxy
Bond strength (wood-to-wood)	Excellent — 10–15 MPa typical	Excellent — 10–15 MPa	Excellent — 15–30 MPa
Water resistance	Poor — dissolves in sustained moisture	Moderate to good (Type II/III)	Excellent
Heat resistance	Poor — softens above 50–60°C	Moderate — softens above 60°C	Good — most types stable to 80–120°C
Open time (working time)	Short — 1–5 minutes depending on temperature	5–15 minutes	5–90 minutes depending on formulation
Reversibility	Yes — re-heatable with moisture and heat	No	No
Gap-filling	Poor — best in tight joints	Moderate	Excellent
Creep resistance	Excellent under dry conditions	Moderate — PVA creeps under sustained load	Excellent
Shelf life (prepared)	Hours (must be used hot)	Months to years (in sealed container)	Months to years
Shelf life (dried cake)	Years	N/A	N/A

Where hide glue works well: Woodworking joints (mortise and tenon, dovetails, edge joints), furniture construction and repair, veneering and marquetry, bookbinding, paper-to-paper bonding, sizing and surface preparation, musical instrument construction, and general indoor bonding of wood, paper, leather, and cloth.¹³

Where hide glue is inadequate: Any application exposed to sustained moisture or immersion. Exterior construction. Marine applications. Any application requiring heat resistance above 50°C. Any bond that cannot be clamped and held during the short open time. Metal-to-metal, plastic-to-plastic, or glass bonding. Structural bonds under dynamic or impact loading.

2.5 Quality grades

Hide glue is graded by gel strength (Bloom number — the force in grams to depress a standard plunger into a gel).¹⁴ High Bloom (250–350 g) glue provides the strongest bond with the shortest open time — best for structural woodworking. Medium Bloom (175–250 g) is the general-purpose grade. Low Bloom (50–175 g) has longer working time and weaker bond — suitable for bookbinding and paper sizing. Bloom strength depends on source material (hide is stronger than bone), extraction number (first extraction is strongest), and processing care. NZ production should grade output by quality, reserving high-Bloom glue for structural woodworking.

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3. CASEIN GLUE

3.1 What casein glue is

Casein is the primary protein in cow’s milk, constituting approximately 80% of milk protein content. When separated from milk (by acidification or enzymatic action) and treated with an alkali (lime or sodium hydroxide), casein forms a strong, water-resistant adhesive that was the standard for wood bonding in the aviation and construction industries from the early 1900s through the 1940s.¹⁵ De Havilland Mosquito aircraft — one of WWII’s most effective combat aircraft — were constructed with casein-bonded plywood and timber.¹⁶

3.2 NZ raw materials

NZ is one of the world’s largest dairy producers and a significant exporter of casein. Fonterra, NZ’s dominant dairy cooperative, produces approximately 100,000–200,000 tonnes of casein and caseinates per year — most exported as food-grade protein ingredients.¹⁷ Under recovery conditions, this production capacity (reduced proportionally with dairy herd reductions under nuclear winter — Doc #75) could supply both food and adhesive needs.

Key advantage: NZ already has the industrial infrastructure to produce casein at scale — spray driers, acid casein plants, rennet casein facilities. The conversion from food-grade casein to adhesive-grade casein requires no additional equipment. The adhesive is formulated at the point of use by mixing casein powder with lime and water.¹⁸

Competing demand: Casein is also a valuable food protein. Under rationing, allocating casein to adhesive rather than nutrition requires justification. The adhesive demand is small relative to total casein output — perhaps 100–500 tonnes per year nationally for adhesive, versus tens of thousands of tonnes produced. The allocation is justifiable but should be explicit.

3.3 Production and formulation

Casein adhesive preparation (at point of use):

1. Mix casein powder with water at a ratio of approximately 1:2 by weight (casein to water). Allow to soak for 15–30 minutes until the casein absorbs the water and swells.
2. Add slaked lime (calcium hydroxide) at approximately 10–20% of the casein weight. Stir thoroughly. The lime reacts with the casein protein, making it soluble and creating the adhesive.
3. Stir until smooth — the mixture should have the consistency of thick cream. If too thick, add small amounts of water.
4. Use within 4–8 hours — casein glue has a limited pot life. Once mixed, the alkaline reaction continues and the glue eventually becomes too thick to apply and loses strength. Do not attempt to re-thin with water after the pot life has expired.¹⁹

Alternative alkali: Sodium hydroxide (caustic soda — Doc #112) can substitute for lime. Sodium hydroxide-casein glues generally have slightly higher water resistance than lime-casein formulations. Borax (sodium tetraborate) mixed with lime has historically been used to enhance water resistance, but NZ borax supplies depend on Australian import.²⁰

Dependency chain: - Casein powder (from NZ dairy industry — available) - Lime or caustic soda (from NZ limestone or salt electrolysis — Doc #112) - Water (available) - Mixing vessel and stirring implement

3.4 Performance characteristics

Property	Casein glue (lime-casein)	Hide glue	PVA
Bond strength (wood-to-wood)	Very good — 8–12 MPa	Excellent — 10–15 MPa	Excellent — 10–15 MPa
Water resistance	Moderate — resists intermittent wetting, degrades under prolonged immersion	Poor	Moderate to good
Mould resistance	Poor without preservative — casein is nutritive substrate for fungi	Moderate	Good
Working time (pot life)	4–8 hours	1–5 minutes	5–15 minutes
Gap-filling	Good — better than hide glue	Poor	Moderate
Assembly time	Long — allows complex assemblies	Very short	Moderate
Temperature resistance	Moderate — stable to ~60–70°C	Poor above 50°C	Moderate
Creep	Low	Low	Moderate

Key advantages of casein glue over hide glue: Longer working time (hours vs minutes), better water resistance, good gap-filling, room-temperature application (no heating required). These properties make casein glue better suited to construction-scale work, plywood manufacture, and applications where complex assemblies must be positioned before the glue sets.²¹

Mould vulnerability: Casein glue’s most serious weakness is susceptibility to mould and fungal attack. Under warm, humid conditions, casein-bonded joints can be colonised by moulds that degrade both the glue and adjacent wood. Adding small amounts of copper sulfate (if available from mining stocks or agricultural supply — see Doc #7), sodium fluoride, or other biocides mitigates this. In NZ’s humid climate, particularly in northern regions, mould resistance is a genuine concern for casein-bonded products in exposed or semi-exposed applications.²²

3.5 Plywood production

Why this matters: Plywood is arguably the most important adhesive-dependent product. It is a structural material used in construction (wall sheathing, flooring, roofing), boatbuilding (hull planking — Doc #141), packaging, and furniture. NZ has historically manufactured plywood — Nelson Pine Industries (now Wengfu NZ) in Richmond, Nelson, and several other operations — using phenol-formaldehyde or urea-formaldehyde synthetic resin adhesives.²³

Casein-bonded plywood: Before synthetic resins became dominant in the 1940s–1950s, casein glue was the standard adhesive for plywood manufacture. Casein plywood is suitable for interior applications and for exterior use where protected from sustained wetting (covered, painted, or sealed). It is not suitable for marine-grade plywood or applications with continuous water exposure — here, synthetic resins are genuinely superior and cannot be replicated with NZ materials.²⁴

Feasibility for NZ: NZ has the veneer-peeling equipment (at existing plywood plants), the timber resource (radiata pine — Doc #99), and the casein supply (dairy industry). Producing casein-bonded plywood is technically feasible in Phase 2–3, provided existing plywood manufacturing equipment can be maintained and operated. The resulting plywood will be adequate for most construction applications but will not match the weather resistance of phenol-formaldehyde-bonded marine plywood. This is a real performance gap that boatbuilders (Doc #141) and exterior construction must account for.

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4. PINE PITCH AND WOOD TAR

4.1 NZ source material

NZ’s 1.7 million hectares of radiata pine plantation forest (Doc #99) provide an abundant source of both resin (from living trees) and wood tar/pitch (from thermal processing of pine wood). Radiata pine produces resin readily — it is a notably resinous species, which is one reason it is considered non-durable for construction (the resin attracts insects and does not protect against fungal decay).²⁵

Two distinct products:

• Pine resin (rosin and turpentine): Collected from living trees by tapping — cutting shallow grooves in the bark and collecting the sap that flows out. The crude resin (oleoresin) can be distilled to separate volatile turpentine (a solvent) from solid rosin (a hard, brittle resin). Resin collection has no significant precedent in NZ, but was a major industry in the southern United States, France, Portugal, and China well into the 20th century.²⁶
• Wood tar and pitch: Produced by pyrolysis of pine wood — the same process used for charcoal production (Doc #102). When pine wood is heated in a low-oxygen environment (retort kiln), the volatile compounds condense as a dark, viscous liquid — wood tar. Further refining (cooking down to remove water and lighter fractions) produces pitch — a thick, sticky to brittle substance depending on the degree of processing.²⁷

4.2 Pine resin collection and rosin

Standing radiata pines can be tapped by scoring diagonal cuts into the bark and collecting the sap that flows out over days to weeks. A single tree can yield 1–4 kg of crude resin per year, depending on tree size, health, and season.²⁸ Crude resin heated in a retort or still separates into turpentine vapour (15–25% by weight — a useful solvent for paint, varnish, and cleaning) and solid rosin (65–75% — a hard, amber-coloured thermoplastic resin).²⁹

Rosin applications: Rosin is not a strong structural adhesive on its own, but it is valuable as a tackifier for other adhesives, a component of varnish and sealing wax, a flux for soldering (Doc #91), and a sizing agent for paper (Doc #29).

NZ production potential: If 1–5% of NZ’s plantation pines were tapped, production could reach 50–1,000 tonnes of crude resin per year. This is speculative — NZ has no established resin tapping industry and the labour intensity is significant. Under nuclear winter, resin flow may be reduced by lower temperatures. Resin tapping would likely develop as a cottage industry in forestry regions (Bay of Plenty, Waikato, central North Island).³⁰

4.3 Wood tar and pitch production

Integration with charcoal production: The most efficient route to pitch production is as a byproduct of charcoal making (Doc #102). Retort kilns designed to capture volatile byproducts collect wood tar as a condensate during the carbonisation process. Every retort kiln should be set up to capture this material — it requires only a condensation pipe and collection vessel. Earth mound kilns and simpler designs do not capture tar effectively.³¹

Yield: Radiata pine produces approximately 10–15% of its dry weight as tar and pyroligneous acid (wood vinegar) during carbonisation. From 1 tonne of dry pine wood, expect approximately 50–100 litres of crude wood tar (mixed with pyroligneous acid), 250–400 kg of charcoal, and the remainder as non-condensable gases.³²

Refining tar to pitch: Crude wood tar is heated gently in an open vessel to evaporate water and lighter fractions. The residue becomes progressively thicker. The degree of cooking determines the final consistency — from a thick, pourable liquid (suitable for waterproofing and wood preservation) to a hard, brittle solid (suitable for caulking and sealing). The entire range of consistencies has practical applications.

4.4 Applications as adhesive and sealant

Caulking and sealing (the primary application): Pine pitch mixed with fibrous material (oakum, hemp fibre, or harakeke fibre — Doc #100) has been the standard caulking material for wooden boats for millennia. The fibre is driven into seams between planks, and hot pitch is poured over to seal. This provides a flexible, waterproof seal that accommodates the movement of timber as it swells and shrinks.³³

Waterproofing: Pine tar applied to timber surfaces provides weather protection and moderate decay resistance. This is directly relevant to construction (roof timbers, exterior cladding) and boatbuilding (hull protection). Pine tar is the basis of Stockholm tar — the traditional Scandinavian wood preservative still commercially produced and used. NZ can produce an equivalent product from radiata pine.³⁴

Adhesive (limited): Pitch alone is a weak adhesive — it bonds by surface adhesion when heated and applied hot, but has low tensile and shear strength. It is useful for adhering cloth to surfaces (waterproofing fabric), sealing containers, attaching labels or markings, and similar light-duty applications. It is not suitable for structural wood joints or any application requiring significant bond strength.

Blending: Pitch blended with beeswax produces a more flexible, easier-to-work sealant. Pitch blended with tallow produces a softer, more pliable caulking compound. Pitch blended with rosin produces a harder, more adhesive sealing wax. These formulations can be tailored to specific applications through experimentation with blend ratios.

Traditional Māori waterproofing methods used functionally equivalent techniques. These waterproofing methods become directly relevant as synthetic sealants deplete. Waka (canoes and ocean-going vessels) represented the most demanding application of traditional waterproofing technology — a waka taua or waka hourua had to be watertight under hard use in open sea conditions, a more demanding specification than most recovery-context applications.³⁵

Waka caulking: Seams in carved and assembled waka hulls were caulked with harakeke fibre driven into the joint, sealed with a mixture of tāpiri (shark liver oil) and ground pigment, and sometimes further treated with tree resins. The combination of compressed fibre and oil-based sealant is functionally equivalent to the pitch-and-oakum caulking used in European wooden shipbuilding — it accommodates timber movement while maintaining a waterproof seal.³⁶

Hinu (oils and fats) as waterproofing: Māori used a range of animal and plant oils (tāpiri from sharks, hinu from various sources) to waterproof and preserve both waka hulls and structural timber. Regular treatment of timber with oil-based compounds is an established preservation method — the principle is identical to Stockholm tar or linseed oil applied to European timber construction.³⁷

Tuna (eel) fat and other animal fats: Various animal fats were applied to wood and fibre for waterproofing and preservation. The specific performance characteristics vary by fat type; all fatty-acid-based waterproofing has the same basic mechanism (filling pores and surface irregularities, reducing water absorption). These applications are directly transferable to recovery conditions.

4.5 Kauri gum (kapia)

Kauri gum becomes relevant as synthetic adhesives and varnishes deplete.

Kauri (Agathis australis) produces one of the most remarkable natural resins documented anywhere. Kauri gum — also called kapia in te reo Māori — is a hard, amber-coloured resin exuded by kauri trees. It accumulates both as tree exudate (from wounds in living trees) and as subfossil deposits in the ground from trees that fell thousands of years ago. The subfossil (“buried” or “swamp”) gum was harvested commercially in Northland and the Waikato from the 1840s through the early 20th century, with peak exports reaching tens of thousands of tonnes per year.³⁸

Adhesive and sealing properties: Kauri gum is hard and brittle at room temperature but becomes adhesive and pliable when heated. It can be used as a hot-melt adhesive — applied to surfaces at temperature, it bonds well to wood and fibre and sets hard on cooling. Ground and dissolved in alcohol or turpentine, it produces a high-quality varnish. Mixed with other resins (pine rosin, beeswax), it produces sealing compounds with excellent weather resistance.

Māori use: Kapia was used by Māori as a sealant and adhesive, including for waterproofing of containers and for adhering harakeke fibre and other materials. It was also chewed as a confection and used in tattooing ink. Iwi in Northland (Ngāti Whātua, Te Rarawa, Ngāpuhi) hold detailed knowledge of kapia sources, properties, and uses that extends well beyond what was documented in the gum-digging industry literature.³⁹

Recovery relevance: Kauri trees are protected under the New Zealand Kauri Dieback legislation, and harvesting living trees is not appropriate. However, ground-deposited subfossil kauri gum remains in soils throughout Northland and the greater Auckland region. Under recovery conditions, with appropriate iwi and hapū engagement, some of this resource may be accessible. The varnish and sealant applications are directly useful for boatbuilding (Doc #141), printing (Doc #29), and woodworking. Iwi and hapū expertise should be engaged before any extraction programme is designed.⁴⁰

4.6 Native tree resins

Tōtara and mataī resins: Several native conifers produce resins that Māori used as sealants and preservatives. Tōtara (Podocarpus totara) and mataī (Prumnopitys taxifolia) exude resins from damaged bark that have adhesive properties similar to pine pitch — though less abundant than radiata pine production.⁴¹

Harakeke (NZ flax) gum: The bases of harakeke (Phormium tenax) leaves produce a sticky, gelatinous gum. This was used by Māori as a binding and stiffening agent. It is not a high-strength structural adhesive, but it is useful as a paper sizing agent, a fabric stiffener, and a light-duty binder for fibre composite applications.

Pōhutukawa and related species: Some Māori traditions record use of saps from coastal trees (including pōhutukawa, Metrosideros excelsa) in waterproofing and sealing applications. The specific properties and application methods are held in tribal knowledge that should be documented and evaluated. This document cannot claim more precision than the available record supports — but the general principle that coastal and forest peoples developed adhesive systems from locally available trees is well-founded.

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5. BEESWAX AND TALLOW SEALANTS

5.1 NZ beeswax supply

NZ’s beekeeping industry manages approximately 900,000–1,000,000 hives producing approximately 15,000–25,000 tonnes of honey per year.⁴² Beeswax is a byproduct of honey extraction — approximately 1–2 kg of beeswax per 100 kg of honey, yielding an estimated 150–500 tonnes of beeswax per year nationally.⁴³ Under nuclear winter, bee populations and honey production will decline — the severity depends on temperature, flower availability, and management. Even with significant reductions, NZ beeswax production of 50–200 tonnes per year is plausible.

Beeswax competes among multiple uses — candles (Doc #34), lubricant additive (Doc #34), leather treatment (Doc #34), and sealant production. The total supply is modest but adequate if allocated carefully.

5.2 Beeswax properties

Beeswax melts at 62–65°C, is water-repellent, flexible at ambient temperatures, adheres well to wood and leather, and is non-toxic. It is not a strong adhesive but is an excellent sealant and waterproofing agent.⁴⁴

5.3 Sealant formulations

Beeswax-tallow blend (general-purpose sealant): 50–70% beeswax, 30–50% tallow by weight. Melted, mixed, and poured or applied hot. Sets to a firm but flexible solid. Suitable for sealing container lids, waterproofing leather, coating cord and thread (makes thread easier to sew through leather and canvas), and light caulking. Melting point lower than pure beeswax — approximately 45–55°C depending on ratio. Not suitable for applications exposed to direct sun in summer or sustained temperatures above 40°C.

Beeswax-pitch blend (weather-resistant sealant): 30–50% beeswax, 50–70% pine pitch. A harder, more weather-resistant sealant. Suitable for exterior caulking, sealing joints in roofing, and waterproofing applications where pitch alone would be too brittle in cold weather. The beeswax adds flexibility; the pitch adds adhesion and weather resistance.

Beeswax-rosin sealing wax: 40–60% rosin, 20–40% beeswax, 10–20% tallow. A traditional sealing wax formulation. Applied hot, sets hard. Suitable for sealing bottles, jars, and containers; waterproofing knots in rope; and general-purpose sealing.

Tallow-based sealant (when beeswax is scarce): Pure tallow or tallow with a small amount of beeswax (10–20%) can serve as a basic sealant for temporary applications. It is softer and less water-resistant than beeswax-based sealants, but it is available in large quantities (Doc #34) and adequate for non-critical sealing.

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6. BLOOD ALBUMIN GLUE

Blood albumin — protein extracted from animal blood — was historically used as a water-resistant adhesive for plywood production, commercially significant from approximately 1910 through the 1940s.⁴⁵ NZ’s meat processing industry generates millions of litres of blood annually as a slaughter byproduct (approximately 10–20 litres per bovine, with 2.5–4 million cattle processed per year).⁴⁶

Dependency chain: - Animal blood (from NZ meat processing — available in large volumes) - Separation equipment — centrifuge or settling tanks to separate serum from clotted blood - Low-temperature drying capacity (below 70°C) — to produce soluble albumin powder without premature denaturation - Lime — calcium hydroxide (from NZ limestone — Doc #97) - Hot press capable of 100–130°C and sustained pressure (existing plywood plant equipment — Doc #99) - Veneer and plywood manufacturing infrastructure

Production: Blood serum is separated from clotted blood, dried at low temperature (below 70°C) to produce soluble albumin powder, mixed with water, lime, and extenders, then applied to veneer surfaces and cured by hot-pressing at 100–130°C for 5–15 minutes. The heat denatures the protein irreversibly, creating a water-resistant bond.⁴⁷

Significance: Blood albumin glue’s primary value is for plywood production where hot-pressing equipment is available. The requirement for heat curing makes it unsuitable for field use or furniture assembly. Its water resistance is better than casein but significantly worse than phenol-formaldehyde resin. It is a second-tier plywood adhesive option — useful if casein supply is constrained by competing food demand.

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7. WHAT NZ CANNOT PRODUCE

An honest assessment must identify the gaps that natural adhesives cannot fill.

7.1 Epoxy and structural adhesives

Epoxy resins are produced from epichlorohydrin and bisphenol-A — both derived from petrochemical feedstocks through industrial chemistry that NZ cannot replicate. Epoxy provides uniquely high strength, gap-filling capability, water and chemical resistance, and the ability to bond dissimilar materials (metal to wood, glass to metal, concrete to steel). There is no natural adhesive that approaches epoxy’s combination of properties.⁴⁸

Applications that lose coverage: Structural bonding in boatbuilding (particularly composite construction), reinforcement of timber joints in construction, metal bonding, concrete repair, and any application requiring waterproof structural adhesive.

Mitigation: Reserve existing epoxy stocks for applications with no alternative. Design around the absence of epoxy — use mechanical fasteners, traditional joinery, and natural adhesives where possible. Boatbuilding (Doc #141) should emphasise traditional plank-on-frame construction (which uses mechanical fasteners and caulking) over modern epoxy-composite methods.

7.2 Silicone sealants

Silicone sealants are produced from silicone polymers derived from silicon metal and chloromethane — industrial chemistry beyond NZ’s capability. Silicone provides permanent flexibility, weather resistance, waterproofing, and adhesion to glass, metal, and tile that no natural sealant matches.

Applications that lose coverage: Bathroom and kitchen sealing, window glazing, roof flashing, plumbing joints, electrical insulation.

Mitigation: Substitute with pitch-beeswax blends for exterior sealing (inferior weather resistance). Use linseed oil putty for window glazing (Doc #98 — a traditional approach that works but requires maintenance). Use thread sealants (tallow or beeswax on pipe threads) for plumbing. Use mechanical compression fittings rather than sealant-dependent joints where possible.

7.3 Contact cements and pressure-sensitive adhesives

Contact cements (neoprene or polychloroprene dissolved in solvent) and pressure-sensitive adhesives (the adhesive on tapes, labels, and bandages) require synthetic polymer chemistry. No natural substitute exists for the instant, flexible bonding that contact cement provides, or for the tacky, pressure-activated adhesion of tape.

Applications that lose coverage: Laminate bonding (benchtops), shoe sole attachment, flexible material bonding, adhesive tape for packaging and medical use, labels.

Mitigation: Shoe soles — use stitching and pegged construction (traditional methods, adequate but more labour-intensive). Packaging — use string, staples, and paper tape with hide glue. Medical bandages — use cloth wraps secured with ties or clips rather than adhesive tape. Labels — use hide glue or casein paste (the traditional approach before pressure-sensitive labels existed).

7.4 Summary of unbridgeable gaps

Application	Required adhesive	NZ substitute	Performance gap
Structural bonding (marine, exterior)	Epoxy or resorcinol	None — use mechanical fasteners	Complete loss of capability
Marine-grade plywood	Phenol-formaldehyde resin	Casein (interior plywood only)	No waterproof plywood production
Waterproof flexible sealing	Silicone sealant	Pitch-beeswax blends	Significant — shorter life, less flexible
Metal-to-metal bonding	Epoxy, anaerobic	None — use mechanical fasteners	Complete loss
Adhesive tape	Pressure-sensitive adhesive	Cloth + hide glue (not equivalent)	Major — no instant tack, no flexibility
Contact bonding (laminates, shoe soles)	Contact cement	None — use mechanical methods	Requires design change

These gaps are real and consequential. They do not invalidate the natural adhesive programme — NZ can meet an estimated 60–80% of its adhesive needs with local materials⁴⁹ — but these gaps require honest acknowledgment and design adaptation across construction, boatbuilding, manufacturing, and repair.

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8. LINSEED OIL PUTTY

Linseed oil (from flax seed, Linum usitatissimum — not to be confused with NZ flax/harakeke) is a drying oil that polymerises when exposed to air, forming a hard, water-resistant film. It is the basis for traditional window glazing putty — linseed oil mixed with finely ground calcium carbonate (whiting) until a stiff, dough-like consistency is achieved. Applied to window rebates, it holds glass in place and seals against weather. It remains workable for hours, skins over in days, and hardens over weeks to months. It requires periodic maintenance but provides functional sealing for decades — the standard approach before silicone sealant.⁵⁰

Dependency chain: - Linseed oil (from Linum usitatissimum seed — not currently grown at scale in NZ; requires cultivation in Canterbury or import from Australia) - Screw press or expeller for oil extraction (same infrastructure as canola oil — Doc #34) - Calcium carbonate (whiting) — finely ground limestone (from NZ limestone deposits — Doc #97) - Mixing vessel and kneading surface

NZ production: Linseed is not widely grown in NZ but can be cultivated in Canterbury and other temperate arable regions. It is a cool-season crop that may tolerate nuclear winter conditions. Establishing linseed cultivation is a Phase 2–3 goal. Seed crushing uses the same screw press infrastructure as canola oil (Doc #34). Australia produces linseed (Riverina region) — a potential early sail trade item (Doc #142). NZ has abundant calcium carbonate for whiting from limestone deposits (Doc #97). The constraint is linseed oil supply — existing stocks should be reserved for glazing and essential sealing applications until cultivation is established.

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9. CRITICAL UNCERTAINTIES AND KEY RISKS

Uncertainty	Why it matters	How to resolve
NZ adhesive stock levels by type	Determines depletion timeline, especially for irreplaceable products (epoxy, silicone)	National asset census (Doc #8) and distributor inventory
Hide glue quality achievable at NZ rendering plants	Bloom strength determines suitability for structural woodworking	Production trials at existing rendering facilities
Casein glue performance for plywood in NZ conditions	Mould resistance in humid NZ climate is a genuine risk	Formulation testing with NZ-available biocides; accelerated weathering trials
Radiata pine resin yield and quality	No NZ precedent for resin tapping at scale	Trial tapping programme in plantation forests
Wood tar yield from NZ charcoal retorts	Depends on kiln design and wood moisture content	Monitoring of byproduct capture at existing and new charcoal operations
Linseed cultivation viability under nuclear winter	Essential for putty and paint production; NZ has no established linseed crop	Trial plantings in Canterbury — begin Phase 1
Plywood plant operability without synthetic resin	Can existing NZ plywood plants convert to casein or blood albumin glue?	Engineering assessment of existing equipment compatibility
Epoxy and silicone stock volume	These products cannot be substituted; stock volume determines how long critical applications are served	Detailed inventory through industrial requisition

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10. CROSS-REFERENCES

• Doc #1 — National Emergency Stockpile Strategy (adhesive and sealant requisition)
• Doc #7 — Agricultural and Industrial Consumables (copper sulfate for casein biocide, general industrial chemical stocks)
• Doc #8 — National Asset and Skills Census (inventory of adhesives, workshops, plywood plants)
• Doc #29 — National Printing Plan (binding adhesive for printed materials)
• Doc #34 — Lubricant Production (tallow and beeswax supply, shared feedstocks)
• Doc #37 — Soap Production (competing tallow demand)
• Doc #46 — Lighting (competing beeswax and tallow demand for candles)
• Doc #38 — Fastener Production (mechanical alternatives to adhesive bonding)
• Doc #29 — National Printing Plan (rosin sizing for paper water resistance)
• Doc #75 — Cropping and Dairy Adaptation (casein supply from dairy processing)
• Doc #83 — Beekeeping Adaptation (beeswax supply)
• Doc #91 — Machine Shop Operations (rosin as soldering flux)
• Doc #93 — Foundry Work (mould release agents — tallow, beeswax)
• Doc #98 — Glass Production (linseed putty for window glazing)
• Doc #99 — Timber Processing (pine resin from forestry, timber for all wood-bonding applications)
• Doc #100 — Harakeke Fiber Processing (fibre for pitch caulking and harakeke gum applications)
• Doc #101 — Tanning and Leather (shared hide supply, leather adhesive applications)
• Doc #102 — Charcoal Production (wood tar and pitch as byproduct)
• Doc #104 — Clothing and Textile Manufacturing (adhesive for fabric bonding where stitching is insufficient)
• Doc #112 — Lime and Caustic Soda (lime for casein glue and hide preparation, caustic soda for casein formulation)
• Doc #138 — Sailing Vessel Design (caulking and waterproofing requirements)
• Doc #141 — Boatbuilding Techniques (adhesive requirements for hull construction, plywood; traditional waka waterproofing methods)
• Doc #160 — Heritage Skills Preservation and Transmission (traditional technology systems, partnership framework for engaging iwi knowledge holders)
• Doc #142 — Trans-Tasman and Pacific Trade Routes (linseed oil, epoxy components as priority imports)
• Doc #163 — Housing Insulation Retrofit (adhesive for insulation attachment — may require mechanical alternatives)

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FOOTNOTES

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1. NZ adhesive market data is not readily available from a single public source. The estimate is based on NZ’s market size relative to comparable economies and the product ranges of major distributors (Sika NZ, Selleys/Henkel NZ, Bostik, 3M NZ). Import data can be verified through Stats NZ trade statistics under HS code 3506 (prepared glues and adhesives) and 3214 (sealants and putties). https://www.stats.govt.nz/↩︎

2. The 60–80% estimate is derived from the application-area analysis in Section 7 of this document. Hide glue and casein glue cover woodworking, furniture, bookbinding, paper products, and general workshop bonding — the majority of adhesive applications by volume. The 20–40% gap consists of applications requiring properties (waterproof structural bonding, flexible sealing, instant tack, metal bonding) that no NZ-producible natural adhesive provides. This is an estimate based on application-area coverage rather than measured volume data; the national adhesive inventory (Recommended Action 1) would provide a more precise figure.↩︎

3. NZ casein production: Fonterra is the world’s largest exporter of casein and caseinates. Production figures are reported in Fonterra annual reports and Dairy Companies Association of NZ data. https://www.fonterra.com/ and https://www.dcanz.com/ — The 100,000–200,000 tonne figure is an estimate based on NZ’s dairy processing capacity and product mix. Exact current figures should be verified against industry data.↩︎

4. Hide glue production rates: based on standard hide glue manufacturing practice as documented in historical trade manuals. Fernbach, R.L., “Glues and Gelatine,” Scott, Greenwood & Co., 1907, provides detailed production methods and yield data. A small rendering-scale operation can produce meaningful quantities with modest additional labour.↩︎

5. The 60–80% estimate is derived from the application-area analysis in Section 7 of this document. Hide glue and casein glue cover woodworking, furniture, bookbinding, paper products, and general workshop bonding — the majority of adhesive applications by volume. The 20–40% gap consists of applications requiring properties (waterproof structural bonding, flexible sealing, instant tack, metal bonding) that no NZ-producible natural adhesive provides. This is an estimate based on application-area coverage rather than measured volume data; the national adhesive inventory (Recommended Action 1) would provide a more precise figure.↩︎

6. NZ adhesive and sealant import data from Stats NZ international trade statistics. The dollar figure is a rough estimate based on NZ retail market data and distributor information. Volume in tonnes is more relevant for depletion analysis but not readily available from public sources without detailed HS code analysis.↩︎

7. Post-event consumption estimate based on the assumption that the primary drivers of adhesive demand — new construction, renovation, and consumer packaging — contract sharply under recovery conditions. Continuing demand concentrates in repair and maintenance, boatbuilding, printing, and sealing. The 10–30% range reflects uncertainty about the scale of recovery-era construction and manufacturing activity. The lower bound assumes severe contraction; the upper bound assumes active rebuilding and boatbuilding programmes drawing significant adhesive volume.↩︎

8. Hide glue chemistry: collagen is a triple-helix protein that denatures into gelatin when heated in water above approximately 60°C. The gelatin solution gels upon cooling through reformation of partial triple-helix junctions. Bond strength comes from hydrogen bonding and mechanical interlocking as the glue dries and contracts. See: Frihart, C.R., “Wood Adhesion and Adhesives,” in “Wood Handbook,” USDA Forest Products Laboratory, 2010. https://www.fpl.fs.fed.us/↩︎

9. Hide glue in woodworking: Hoadley, R.B., “Understanding Wood,” Taunton Press, 2000. Also: Tolpin, J., “The Toolbox Book,” Taunton Press, 1998. Hide glue’s continued use in musical instrument construction (particularly stringed instruments) is documented in luthier trade literature. The reversibility of hide glue joints is a significant advantage for repair and restoration work.↩︎

10. NZ hide and skin export data from Stats NZ and Meat Industry Association. https://www.mia.co.nz/ — NZ exports the majority of raw hides and skins, primarily to China and other Asian markets for leather processing. Under recovery conditions, all hides remain in NZ for domestic leather and glue production.↩︎

11. Multiple extraction of hide glue: the first extraction (at lowest temperature, longest time) produces the highest-grade glue. Second and third extractions at progressively higher temperatures yield weaker grades. This is well-documented in historical glue manufacturing texts. See: Alexander, J., “Glue and Gelatine,” Chemical Publishing Co., 1923.↩︎

12. Shelf life of dried hide glue: properly dried hide glue (below 10% moisture) stored in a cool, dry environment is shelf-stable for years to decades. Archaeological evidence suggests ancient hide glues retain some bond strength after centuries. Modern dried hide glue products (marketed for woodworking) typically carry shelf life ratings of 2–5 years, which is conservative.↩︎

13. Hide glue in woodworking: Hoadley, R.B., “Understanding Wood,” Taunton Press, 2000. Also: Tolpin, J., “The Toolbox Book,” Taunton Press, 1998. Hide glue’s continued use in musical instrument construction (particularly stringed instruments) is documented in luthier trade literature. The reversibility of hide glue joints is a significant advantage for repair and restoration work.↩︎

14. Bloom strength measurement: the standard test (ISO 9665) measures the force (in grams) required to depress a standard plunger 4 mm into a standard gel. Higher Bloom numbers indicate stronger gel and, generally, stronger dried adhesive. Commercial hide glue ranges from approximately 50 to 400 Bloom.↩︎

15. Casein adhesive history and properties: Lambuth, A.L., “Protein Adhesives for Wood,” in “Handbook of Adhesive Technology,” 2nd ed., Pizzi, A. and Mittal, K.L. (eds.), Marcel Dekker, 2003. Casein adhesives were the standard for structural wood lamination and plywood from approximately 1900 to 1945.↩︎

16. De Havilland Mosquito construction: Sharp, C.M. and Bowyer, M.J.F., “Mosquito,” Faber and Faber, 1967. The Mosquito was constructed primarily of birch plywood and spruce, bonded with casein adhesive (later aircraft used urea-formaldehyde resin). Over 7,700 were built — demonstrating the adequacy of casein adhesive for structural aviation applications, albeit in a design intended for relatively short operational life.↩︎

17. NZ casein production: Fonterra is the world’s largest exporter of casein and caseinates. Production figures are reported in Fonterra annual reports and Dairy Companies Association of NZ data. https://www.fonterra.com/ and https://www.dcanz.com/ — The 100,000–200,000 tonne figure is an estimate based on NZ’s dairy processing capacity and product mix. Exact current figures should be verified against industry data.↩︎

18. Casein adhesive formulation: standard formulations are documented in Pizzi and Mittal (note 11) and in USDA Forest Products Laboratory publications. The basic lime-casein formulation has been standardised since the early 20th century. See also: Forest Products Laboratory, “Wood Handbook,” Chapter 10 (Adhesive Bonding of Wood Materials), USDA, 2010.↩︎

19. Casein glue pot life: the alkaline reaction continues after mixing, progressively denaturing the casein protein. Working time of 4–8 hours is typical for lime-casein formulations; sodium hydroxide-casein formulations may have shorter pot life. Temperature affects pot life — warmer conditions shorten it. See Lambuth (note 11).↩︎

20. Borax as a casein adhesive additive: borax (sodium tetraborate) improves the water resistance and mould resistance of casein adhesives. NZ does not have known borax deposits. Australia produces borax (Borax Holdings, Western Australia). This is a potential import item via early sail trade. See: Pizzi, A., “Advanced Wood Adhesives Technology,” Marcel Dekker, 1994.↩︎

21. Casein adhesive history and properties: Lambuth, A.L., “Protein Adhesives for Wood,” in “Handbook of Adhesive Technology,” 2nd ed., Pizzi, A. and Mittal, K.L. (eds.), Marcel Dekker, 2003. Casein adhesives were the standard for structural wood lamination and plywood from approximately 1900 to 1945.↩︎

22. Mould resistance of casein adhesive: casein is an excellent substrate for fungal growth under warm, humid conditions. In NZ’s climate, particularly in Northland, Auckland, and Bay of Plenty, mould attack on casein-bonded wood products is a genuine concern. Biocide additives (copper sulfate, sodium fluoride, pentachlorophenol — though the last is toxic and environmentally persistent) were historically used. See: Forest Products Laboratory (note 13).↩︎

23. NZ plywood manufacturing: Nelson Pine Industries (now Wengfu NZ, based in Richmond, Nelson) has been NZ’s primary plywood manufacturer, using radiata pine veneer bonded with phenol-formaldehyde resin. Other NZ plywood operations have included CHH Woodproducts (formerly Carter Holt Harvey). The industry depends entirely on imported resin adhesive feedstocks.↩︎

24. Casein vs synthetic resin plywood: casein-bonded plywood meets interior and semi-exterior standards but not the weather and boil proof (WBP) standard required for marine and fully exterior applications. This distinction was codified in British Standard BS 1455 (now superseded) and equivalent international standards. See Lambuth (note 11).↩︎

25. Radiata pine resin: radiata pine (Pinus radiata) is a medium-resin-content conifer. Its resin production is well-documented in forestry literature. See: Burdon, R.D. et al., “Radiata Pine Breeding in New Zealand,” in “Tree Breeding and Genetics,” various editions. The resin is chemically similar to other pine oleoresins and suitable for rosin and turpentine production.↩︎

26. Naval stores industry (pine resin tapping): the production of turpentine and rosin from pine resin — known as the “naval stores” industry — was a major economic activity in the American South, France, and Portugal for centuries. See: Coppen, J.J.W. and Hone, G.A., “Gum Naval Stores: Turpentine and Rosin from Pine Resin,” FAO Non-Wood Forest Products Series No. 2, 1995. http://www.fao.org/3/v6460e/v6460e.htm↩︎

27. Wood tar production: wood tar from coniferous species is produced by pyrolysis at temperatures of approximately 300–500°C. The Scandinavian tradition of tar production (used for boat waterproofing) is well-documented. See: Hjulstrom, B. and Isaksson, S., “Identification of activity area signatures in a reconstructed Iron Age house,” Journal of Archaeological Science, 2009. Also documented in Doc #102 (Charcoal Production).↩︎

28. Naval stores industry (pine resin tapping): the production of turpentine and rosin from pine resin — known as the “naval stores” industry — was a major economic activity in the American South, France, and Portugal for centuries. See: Coppen, J.J.W. and Hone, G.A., “Gum Naval Stores: Turpentine and Rosin from Pine Resin,” FAO Non-Wood Forest Products Series No. 2, 1995. http://www.fao.org/3/v6460e/v6460e.htm↩︎

29. Turpentine and rosin yield: typical yields from crude pine oleoresin are 15–25% turpentine (alpha-pinene, beta-pinene, and other terpenes) and 65–75% rosin (abietic acid and related diterpenoid acids). See Coppen and Hone (note 20). Actual yields depend on species, resin freshness, and distillation efficiency.↩︎

30. Resin tapping labour intensity: in the American naval stores industry, a single worker could manage approximately 10,000 tapping faces, visiting each periodically to refresh cuts and collect resin. This is labour-intensive relative to other forestry operations. See Coppen and Hone (note 20). NZ has no tradition of resin tapping and would need to develop the skill set.↩︎

31. Wood tar production: wood tar from coniferous species is produced by pyrolysis at temperatures of approximately 300–500°C. The Scandinavian tradition of tar production (used for boat waterproofing) is well-documented. See: Hjulstrom, B. and Isaksson, S., “Identification of activity area signatures in a reconstructed Iron Age house,” Journal of Archaeological Science, 2009. Also documented in Doc #102 (Charcoal Production).↩︎

32. Charcoal and tar yield from radiata pine: approximate yields based on general pyrolysis chemistry for coniferous wood. Exact yields depend on kiln design, heating rate, moisture content, and wood piece size. See Doc #102 for detailed charcoal yield discussion. Tar yield data from: Antal, M.J. and Gronli, M., “The Art, Science, and Technology of Charcoal Production,” Industrial & Engineering Chemistry Research, 2003.↩︎

33. Pitch caulking of wooden vessels: the standard practice for waterproofing wooden boats from antiquity through the early 20th century. Fibrous material (oakum — tarred hemp or jute — or equivalent local fibre) is driven into seams with a caulking iron and mallet, then sealed with hot pitch. See: Chapelle, H.I., “Boatbuilding,” W.W. Norton, 1941. Also referenced in Doc #141.↩︎

34. Stockholm tar: pine tar produced in Scandinavia (primarily Sweden and Finland) by kiln distillation of pine stumps. It was a major export commodity for centuries and remains commercially available. NZ can produce an equivalent product from radiata pine using the same basic process. See: Egenberg, I.M. et al., “Tarring maintenance of Norwegian medieval stave churches,” Journal of Cultural Heritage, 2003.↩︎

35. Waka construction and performance: waka taua (war canoes) and waka hourua (ocean-going double-hulled vessels) were among the most sophisticated watercraft built anywhere without metal tools. Their construction required mastery of timber selection, joining, caulking, and waterproofing using only locally available materials. The performance record — including the original voyaging canoes that settled Aotearoa from Polynesia — demonstrates the adequacy of traditional adhesive and waterproofing systems for demanding marine applications. See: Salmond, A., “Tears of Rangi: Experiments Across Worlds,” Auckland University Press, 2017. Also: Te Ara, “Waka — Māori canoes.” https://teara.govt.nz/↩︎

36. Waka caulking materials: the specific materials used to caulk and seal waka hulls varied by region and availability. Harakeke fibre, pounded bark, and various plant materials served as the fibrous packing component. Animal fats (tāpiri from shark liver and other sources) and tree resins served as the sealing medium. The fundamental engineering principle — compressed fibre plus hydrophobic sealant — is identical to European pitch-and-oakum caulking. See: Haddon, A.C. and Hornell, J., “Canoes of Oceania,” Bishop Museum Press, 1936–1938 (Vol. 2 covers NZ waka). Note that this source reflects its era and tribal knowledge should take precedence on specific NZ detail.↩︎

37. Native NZ timber resins and preservative applications: tōtara (Podocarpus totara) and other native podocarps produce resins with preservative and sealing properties. Traditional use of tōtara timber in waka construction (where durability and water resistance were critical) is well-documented. See: McClintock, A.H. (ed.), “An Encyclopaedia of New Zealand,” Government Printer, 1966, entry on “Timber” and “Waka.” Also: Te Ara, “Waka — Māori canoes.” https://teara.govt.nz/↩︎

38. Kauri gum industry: kauri gum (kapia) was one of NZ’s most important 19th-century exports. At peak production (circa 1900), annual exports exceeded 10,000 tonnes. Ground-deposited subfossil gum formed over thousands of years as kauri trees died and decayed. See: Reed, A.H., “The Story of the Kauri,” A.H. and A.W. Reed, 1952. Also: Te Ara — The Encyclopedia of New Zealand, “Kauri gum and gum digging.” https://teara.govt.nz/↩︎

39. Māori use of kapia: kauri gum had multiple applications in traditional Māori material culture beyond those recorded in settler ethnographic sources. Te Ara notes its use as a chewing gum, tattooing medium, and lighting fuel. The full range of adhesive and sealing applications documented within tribal knowledge is beyond the scope of this document. See: Best, E., “The Maori,” The Polynesian Society, 1924 (noting that this is an early colonial source with its own limitations); and tribal sources via the respective rūnanga of Northland iwi.↩︎

40. Mātauranga Māori as primary technical resource: the position taken here — that iwi and hapū knowledge of material systems must be engaged before, not after, any recovery resource plan is finalised — follows the framework set out in Doc #160 (§4.5–4.7). Written settler-era sources (gum-digging industry records, early ethnographies) are useful but partial and should be treated as corroboration, not primary documentation, where living oral and practical knowledge exists.↩︎

41. Native NZ timber resins and preservative applications: tōtara (Podocarpus totara) and other native podocarps produce resins with preservative and sealing properties. Traditional use of tōtara timber in waka construction (where durability and water resistance were critical) is well-documented. See: McClintock, A.H. (ed.), “An Encyclopaedia of New Zealand,” Government Printer, 1966, entry on “Timber” and “Waka.” Also: Te Ara, “Waka — Māori canoes.” https://teara.govt.nz/↩︎

42. NZ beekeeping industry statistics from Apiculture NZ. https://www.apinz.org.nz/ — NZ had approximately 918,000 registered hives as of the 2022/23 season. Honey production varies annually with weather conditions.↩︎

43. Beeswax yield: the ratio of beeswax to honey varies with hive management and honey extraction method. The 1–2 kg per 100 kg estimate is typical for commercial operations using modern extraction equipment. Traditional honey harvesting (crushing comb) yields more wax but less honey. See: Crane, E., “Bees and Beekeeping: Science, Practice, and World Resources,” Heinemann Newnes, 1990.↩︎

44. Beeswax properties: melting point 62–65°C, density approximately 0.96 g/cm³, excellent water repellency, good adhesion to wood and fibre, non-toxic, food-safe. Well-established in candle making, polishing, waterproofing, and cosmetics. See Crane (note 28) and Doc #34, Doc #46.↩︎

45. Blood albumin adhesive history: blood glue was commercially used for plywood production from approximately 1910 to the 1950s, particularly in the United States. It produced a darker glue line than casein but offered better water resistance. See: Lambuth (note 11). Also: Pizzi, A., “Advanced Wood Adhesives Technology,” Marcel Dekker, 1994.↩︎

46. NZ slaughter blood volumes: estimated from livestock processing data. A 500 kg bovine yields approximately 15–20 litres of blood at slaughter. NZ processes approximately 2.5–4 million cattle per year (numbers vary with herd size and export market conditions). See: Meat Industry Association, https://www.mia.co.nz/↩︎

47. Blood albumin glue formulation and curing: blood albumin adhesive requires heat curing (typically 100–130°C for 5–15 minutes under pressure) to denature the protein irreversibly. This limits its use to hot-press applications (plywood, laminated panels). Cold application produces a weaker, non-water-resistant bond. See: Pizzi (note 30).↩︎

48. Epoxy resin chemistry: epoxy adhesives are thermosetting polymers produced by reacting epichlorohydrin with bisphenol-A (DGEBA — diglycidyl ether of bisphenol-A). Both precursors are derived from petrochemical feedstocks through industrial chemistry that NZ does not have and cannot develop in the foreseeable future. See: Petrie, E.M., “Handbook of Adhesives and Sealants,” 2nd ed., McGraw-Hill, 2007.↩︎

49. The 60–80% estimate is derived from the application-area analysis in Section 7 of this document. Hide glue and casein glue cover woodworking, furniture, bookbinding, paper products, and general workshop bonding — the majority of adhesive applications by volume. The 20–40% gap consists of applications requiring properties (waterproof structural bonding, flexible sealing, instant tack, metal bonding) that no NZ-producible natural adhesive provides. This is an estimate based on application-area coverage rather than measured volume data; the national adhesive inventory (Recommended Action 1) would provide a more precise figure.↩︎

50. Linseed oil putty: the traditional glazing compound — raw linseed oil mixed with finely ground calcium carbonate (whiting). In use for window glazing since at least the 17th century. Hardens over months through oxidative polymerisation of the linseed oil. Requires periodic maintenance (repainting, patch repair) but provides functional sealing for decades. See: Davey, A., et al., “The Care and Conservation of Georgian Houses,” Butterworth Architecture, 1986.↩︎