A while ago I was watching a wood working video and during the course of his work the carpenter used two part epoxy and wood dust to fill some imperfections in his joinery. At the time I thought that epoxy was over kill for the task. There was no commentary related to why epoxy was used and I dismissed it as a 'use what you got' sort of moment.
Recently I have begun work on a piece of fine furniture (a sofa table) with a single 10 inch board for the top. While planing the board a knot broke open potentially ruining the board. Clearly the knot could not be filled with wood dust and carpenter's glue. The board was too nice to discard and the knot would add real character if the hole problem could be solved. The the solution occurred to me, two part epoxy. Epoxy is strong and easy to use, but the patch would be translucent not invisible.
The knot was black and so I decided to colour the epoxy before stuffing it into the hole. Fortunately I did a bit of experimentation before I applied the glue to the finished board. I began by mixing the epoxy and adding water based black wood stain. I guess the water changed the epoxy's chemical reaction, it dried but had a rubbery, soft finish that was not suitable, but the colour was good. I tried again with less stain but got pretty much the same result it seemed that it was not volume of stain but chemical composition.
I decided that I needed something black and prue. The next experiment used:
One centimetre of willow sketching charcoal. I ground it to a very fine powder and mixed it in to the epoxy. The result was a hard, black patch.
|repaired and rough sanded|
Once the patch is finished sanded and varnished I expect the repair to go un-noticed, as repairs should.