Stabilising knife handle materials – Full practical guide

Introduction

Stabilized wood handle material is one of the foundations of modern knife making. The stabilisation process involves saturating the wood pores with resin under vacuum and then curing it under heat to produce a dimensionally stable, workable and durable material. This description is based on the use of our Resin 90 stabilising resin and our own workshop experience.

Stabilising resin vs epoxy resin

The stabilising resin (Resin 90) is low viscosity, deeply absorbed into the wood structure and suitable for vacuum impregnation. Epoxy resin is denser and is not used for stabilisation, but for casting (e.g. for hybrid grips). The two materials are not substitutes for each other.

The most important principle: the wood must be dry

The most critical point of stabilisation is the moisture content of the wood. Wood that is ‘thought’ to be dry often still contains moisture, so it is worth drying it out before stabilisation. Drying can be done in an oven, kiln or kiln-dryer at around 40-50°C, but preferably at lower temperatures and for longer periods. Drying too quickly can cause cracking and warping, which is why it is advisable to work with a margin. It is not possible to achieve completely dry wood, but a minimum moisture content should be sought.

Stabilisation step by step

1. Workpiece preparation: dry, clean, cut to size, pre-drying recommended.
2. Resin placement and weighting: pieces are weighted with a stainless steel weight to prevent floating.
3Vacuum impregnation: -0.90 – -0.95 bar vacuum until bubbles come out of the wood.
4. Soaking at atmospheric pressure: minimum 2-3 hours to allow the resin to soak in.
5. Packaging and heat treatment: bake in aluminium foil at 90-95 °C for 1.5-2 hours.

Weight measurement and resin absorption

It is worth measuring the weight of the workpiece before and after stabilisation. In our experience, some species, such as Karelian birch or alder, can take up to 80-90% of their own weight, but this is always material-dependent and by no means a law. However, if several stabilizations of the same type are used, a good percentage can be a number, which allows us to filter out possible incorrect stabilizations.

Colouring of resin

Resin 90 resin is highly colourable. Use a solvent compatible, concentrated paint, starting with a small amount and mixing thoroughly. Light wood gives a bright colour, dark wood a deeper tone. Our range of allumilite stains are available, these are stains specifically for stabilising resins.

Own workshop experience

With proper drying, stable vacuum and precise heat treatment, Resin 90 stabilization gives reproducible and professional quality. The stabilised grip material is dimensionally stable, highly polishable and has a premium appearance.