It is important to use the correct adhesive for the purpose. Health and safety rules are important when using adhesives.
Each adhesive works on a particular principle and will have its own rule for use and safety!
Protective clothing should be used when working with any adhesive.
PVA (Poly Vinyl Acetate) is a water based adhesive which is white in colour drying to semi-translucent. It soaks into the surface wood fibres then dries to give a strong plastic bond. It dries by evaporation and absorption into the wood. The bond can be stronger than the wood itself.
Epoxy Resin (Araldite) is a two part adhesive which is thoroughly mixed together in equal proportions. A chemical process then begins converting the liquid resin/hardener mix into a tough hard plastic material. This adhesive is expensive but will join most materials which are properly prepared ( clean, degreased, dry, roughened surface or keyed). The join is similar in strength to a weld on some materials. It is used in industry to join a wide range of materials car and aeroplane parts included.
Tensol cement and solvent weld cements. - The solvent dissolves the surface layers of a wide range of thermoplastics. When the surfaces are joined in this way the solvent evaporates leaving a joint made from a mixture of the two plastic surfaces. Acrylic is usually joined with Tensol cement (solvent- dichloromethane). High impact polystyrene and PVC are also joined by solvent cements. Polythene and polypropylene cannot be glued by solvent welding because they will not dissolve in any solvent. Thermosets cannot be glued by this process either.
Contact Adhesive (Evostick) A thin even layer of the adhesive is applied to each surface and allowed to dry for about 10 - 15 minutes. The two surfaces are then pressed firmly together. The bond is instant. This method only works for large surfaces and is particularly useful for non porous surfaces e.g. plastic laminates onto wood or metal.
Health and safety - Do not get the adhesive onto your skin and avoid the fumes by working in a well ventilated area.
Hot melt glue - the glue gun works by heating a stick of glue which resets when cool forming the bond. The glue is a kind of thermoplastic. Very useful for quick modelling. Not often used for final production.
Hot melt glue is used in industry for packaging and some simple assemblies where great strength is not needed. It can also be used for gluing cables to walls etc. by electricians. It comes in a full range of colours.
This glue will blister skin - take care. Rest the glue gun on a heat resistant surface using its built in support.
Synthetic resins (Cascamite) - Used for very strong wood joining. A powder is mixed to a a creamy consistency with water. Applied to both surfaces and clamped up. Remove excess at the gel stage. This resin is very hard when set. This is a chemical reaction to set. Wash hands or wear gloves.
Pritt stick - pva based and used for light gluing of paper and card.
Latex adhesives (Copydex) this is a rubber latex solution, water based, unpleasant ammonia smell. This dries to give a waterproof rubber layer. Used for gluing fabrics.
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