My Stabilising Process
I use a four-step process in my workshops that has been refined and tweaked for a considerable time and produces consistently excellent results.
The four stages are: Drying, Impregnation, Soaking and Curing, and there are more details of each step below.
I weight your materials at key stages throughout the process, so I can be sure they ready for the next stage.
When I’ve finished working on them I’ll send them back to you, and I will also let you know exactly how much moisture was lost in drying, how much resin was absorbed in the vacuum chamber and the soak, and how much total increase there has been between each original piece as it was and as it is now, fully stabilised.
It is extremely important that all material to be stabilised has as little moisture in it as possible. Porous materials by their nature absorb water from the atmosphere, so even if it has been kept in a ‘dry’ environment, the moisture content of your wood will typically be 10–15% of its weight.
All that moisture needs to be driven off.
Drying increases the amount of resin that can be absorbed by the material, and since we are trying to get as much in there as possible, this is obviously a good thing.
I will dry your materials in my ovens until they stop losing weight. At that point, there is no more moisture left to drive out and I can proceed to the next step.
2. Vacuum Impregnation
Once completely dry, the material is fully immersed in a high-quality specially designed thermo-cure methacrylate resin in a vacuum chamber. A very powerful vacuum is applied, the air trapped in the wood bubbles out furiously, and after generally somewhere between an hour and 24 hours, there will be no more air to suck out of the material.
Once all the air has been sucked out, the vacuum is released, and the materials transferred to a soaking-vat full of resin. The chamber has left the internal structure of the material under vacuum. It has already absorbed some resin but during the soaking period, atmospheric pressure will push more resin inside.
The soaking phase lasts generally 24 hours but can be up to a few days, and it will typically cause the material to increase in weight by around another 20% – 40%, from when it first came out of the vacuum chamber.
I check the weight of the material regularly during soaking, and only move on to the next stage when it has stopped absorbing resin.
The final stage is to cure the resin; this is the process that makes it harden. I use two methods, depending on the size and type of material. I have built my own precisely regulated ovens, and I also use a hot-water curing system.
There is always a small amount of resin lost during this process, which varies considerably by material type, but by tweaking my methods I have managed to get this down to a small percentage in the majority of cases. Where there is excessive seepage I will often perform a ‘second pass’, repeating the entire process to fill gaps created by the seepage.