Gluing Wood Successfully
Ireland has a very long history of woodworking and wood glue and it is a traditional craft that involves many demanding applications for our wood glues. Like the craftsman of decades ago, the craftsman of today needs the traditional values of cabinet making, linked with cost-effective production methods that utilise the new raw materials which make up today’s kitchen units, worktops, doors, furniture and window frames.
Here at W.I Polymers, we develop, manufacture and supply a range of high quality wood adhesives that cover most of the applications typically seen including dowelling, jointing, flat lamination and profiling.
Most wood is easy to glue and it is generally possible to obtain good bond strength with most woods. Some wood species have certain characteristics which may make gluing more difficult. Some wood is highly absorbent, while some types are very dense and some are very hard.
Tips for Bonding Wood
The glue must be mixed correctly. Even though wood adhesives like our W26 do not settle out during storage, they should be stirred before use. Always apply the correct of adhesive to the wood. Typically 150g to 300 g per square meter. For laminating sheets of timber, apply the adhesive with a knife with a serrated blade. Use a bottle or brush when applying adhesives to joints and always apply sufficient clamp pressure to the joints. Be careful as high clamping pressure will cause excessive squeeze-out and the glue-line will become starved of adhesive.The wood should be dry with a moisture content of well below 20%, 15% being the optimum figure. If the wood being glued has a high moisture content, there is a danger that the bonds will crack as the moisture content of the wood decreases. The surface of the wood should be flat, freshly cut and planed. Wood should always be free from all contamination including dust etc. All of our detailed instructions for the correct mixing and spreading of the adhesive should be followed exactly. Irish workshops are typically cold in the winter months and it is not uncommon to get customer complaints at this time. The most complaint may be due to the attempted use of frozen adhesive. If the glue is cold (below 5°C) it will not flow well. Lower than 5°C there is the danger that the glue will not cure properly. At close to freezing point, the glue will dry to the consistency of a white powder with no adhesion qualities. If this happens, the only remedy is to clean down the areas to be bonded with a scouring pad and glue again. After gluing, leave the assembly for approximately 24 hours. Below are some tips for bonding various types of timber.
Use a very high quality wood adhesive such as our W26 or W106. It is a good practice to ‘prime’ the surface of the wood with a thin coat of W26 first and allow this to dry before the second coat is applied. Increase the spread rate of the adhesive. Mixing 200g of glue with 800g of fresh cold water is suggested.
Resinous timber can be very problematic. We suggest lightly sanding the surface of the areas to be bonded and immediately following this, degrease the surface with solvents such as T160 or Orange Solvent. If the job allows, use one of our polyurethane adhesives such as DP462 or DP463.
Timber prone to staining
Do not use acidic wood adhesives to bond timbers prone to staining. Ensure that the adhesive does not come into contact with any steel fixings or clamps used to clamp the timber together. The jaws of the clamp should be covered with a plastic bag. The optimum adhesive to use is our tannin resistant wood adhesive DP 465. This adhesive will not discolour when used with timber which is prone to staining.
Machine or lightly sand the surface. Apply the adhesive to both surfaces to be joined and ensure that there is no open assembly time to allow partial drying of the adhesive. Bond the assembly immediately. Apply light clamping pressure. High clamping pressure will cause excessive squeeze-out and the glue-line will become starved of adhesive.
Keep the moisture content of the adhesive below 12%. It is suggested to neutralise the surface of the timber with a 1% baking soda solution. Apply with a brush.
Specific Wood Characteristics
|Absorbent Wood||Resinous Wood||Wood prone to staining||Dense Wood||Acidic Wood|
|Obeche||Yang||Panga Panga||Tallow Wood||Cedar|
At W.I Polymers, we are dedicated to high quality adhesive production. Our experience, technical capability and modern manufacturing plant benefit from the support of a technical team who are in constant touch with new developments in the woodworking sector. In order to ensure that our adhesives keep pace with evolving needs, work closely with machinery manufacturers such as Burkle, Grecon and Hymmen.
Discuss your problems with our Technical Department. If an existing product is not suitable, we will quickly prepare an individual formulation to suit your needs.