Wood Moisture & Wood Gluing.
Do you love your wood?
Woodworking is a craft that involves many demanding applications for glues, and as the best known manufacturer and supplier of wood glue in Ireland, we are dedicated to supplying the woodworking sector with glues that give the required performance characteristics for almost all applications.
Over the years, we have developed a number of cutting-edge wood glues for carcase assembly, dowelling, V grooving and all aspects of flat lamination. One questions which regularly comes to light, is the relationship between the moisture content of wood and potential gluing issues.
First of all, I must point out that wood is not dimensionally stable. As the moisture content of the wood changes, the wood will expand and contract and this can lead to various issues. And how is moisture content calculated? Well it’s a simple measurement between the weight of the water in the wood and the weight of the wood itself. We normally express this as a percentage.
To give you an idea of the moisture content of wood during different stages of it’s life. Freshly cut wood may have a moisture content of well over 30% and before it can be used, this moisture content must be reduced. For most internal applications, the wood should have a moisture content of in and around 9% to 12%. In most situations, the moisture content of the wood will depend on two factors; the use of the wood and the annual average relative humidity at the place where the wood is to be used.
In an ideal situation, the moisture content of the wood should be dried to within a few per cent of the moisture content of the location where it will be finally installed. Since Ireland has a damp climate, and the typical indoor humidity is between 50% and 60%, glued wood can be subjected to significant structural movement.
So what are the five key defects which our laboratory often hear about?
- Delaminating of flat surfaces. This may be due to laminates of different moisture content, being used.
- Failure of laminated veneers. Solid lipping’s, especially those which are used occasionally, may have dried out excessively.
- Split laminates. Wood shrinking as it dries.
- Post sanding grain issues. The wood fibres should be sanded smoothly. Rough fibres are prone to prone to picking up humidity.
- Laminates which curve. A possible cause is often due to two different types of facing material being used.
Is there a way to prevent the occurrence of these defects? Yes there is, and the best and only way, is to know the humidity of the wood. This will avoid a serious amount of heartache.
Our laboratories are always available to offer the best wood gluing advice. We can also suggest the optimum glue for your wood gluing applications. All of our wood glues are developed and manufactured in Ireland.