The thermoplastic handle scales on my folk’s Wüstof knife broke, and I thought I’d replace it with some wood scales. I had some offcuts of claro walnut that were the right size, but I wanted to make sure that the new walnut scales would hold up to kitchen use.
I did a little research in some knife-making web sites and forums and learned a bit about wood stabilization, where you impregnate wood with some material (epoxy, resin, etc.) to harden it and make it more durable. Some home knife makers just soak the wood in polyurethane, but the better method is apparently to put the wood in a container with the poly and put it under pressure by using a vacuum pump. This pulls the air out of the wood and allows the poly to fully absorb into the wood. This same technique could be used on pen blanks or other small pieces of wood that need to be stabilized (punky spalted turning blanks, maybe?)
We have a hand wine vacuum pump to take out the oxygen so you can preserve opened bottles for a few days. The same pump and nozzles are used for doing vacuum bag lamination in woodworking, so I figured it would add enough pressure for this project. I ordered an extra pack of nozzles, took a tall canning jar, and cut a hole for the nozzle in one of the tops using a spade bit in my egg beater drill.
I originally thought I would have to seal the sides around the hole with caulk, but a test with an empty jar showed that the nozzle was holding pressure on its own.
I put the walnut scale blanks in the canning jar, then filled it with a bottle of Minwax Wood Hardener (which is just poly with a bunch of solvent, apparently) and some Minwax wipe-on poly thinned with mineral spirits. I had to leave enough air space for the end of the nozzle, so the blank ended up being not completely submerged. Then I used the pump to create the vacuum pressure. Small air bubbles immediately started coming out the wood.
Now I get to wait and let it absorb under pressure.
-- ian | "You can't stop what's coming. It ain't all waiting on you. That's vanity."