As summer approaches and yard work threatens to monopolize my time, large projects in the shop have to take a back seat. Faced with a little free time over last weekend I decided I could squeeze in a small weekend project, and maybe even find a way to incorporate Lichtenberg figures. After taking stock of the materials I had on hand, I decided to make a tealight candle holder, since I had some tealights leftover from lathe projects I had done in the past. As always, the first question to answer is what wood to use, so my first step was to do a little experimenting.
The first pieces I cut were two pieces of poplar and a piece of mahogany. These were chosen because they were small cut-off pieces from other projects that were already about the right thickness, and they were close to the top of my wood pile. I also pulled out some small pieces of maple and walnut, but they would need to be planed, so I saved those for batch two. I cut the wood to size and drilled the holes for the tealight candles. I found in previous experiments that in order for the figures to work well in harder woods they needed two or three coats of electrolyte solution, and time to absorb between coats, so I went ahead and prepped the wood for burning. Below are my experiments and observations burning the first three pieces. I really do learn something new every time I get this machine out.
The top piece in the picture above was the first piece. The problem seemed to be that too much of the electrolyte solution dripped over and soaked into the edges of the piece, causing most of the burning to take place on the edge, not the surface. The bottom piece above was the second burn. For this one I made sure not to paint the electrolyte all the way to the edge, leaving a thin, dry boarder around the edge of the surface. Unfortunately the poplar proved too eager to catch fire and burn, leaving thick smudgy lines, which was not the desired effect. So far, two pieces burned, two lessons learned. Just when I was getting a little discouraged, the third piece (in the middle above) brought me a pleasant surprise. While I was hoping for a little more detail, the mahogany burned like no other wood I had tried previously. On other woods the pattern started at both electrodes and snaked through the wood until the two ends got close enough to arc. On the mahogany, the burn seemed to start instantaneously all throughout the wood and quickly begin to arc.
Based on that experiment, I decided that Mahogany might be the wood to use for this project. On the bright side, I happen to have some lying around, but on the other side, it is very expensive, and I hate to use it on a dinky little project like this. In the long run I decided to go ahead and use a little of the Mahogany I had on hand. What's the point in having it if I never use it for anything, waiting for that perfect project that never comes. I ripped a length of it, planed it down to a little over a quarter inch, and cut that length into four pieces ready to be burned. Below is the result.
I was very pleased with the way these turned out. You'll notice in the picture that each of these pieces has a lighter area around the boarder. This is a result of not painting the electrolyte solution all the way to the edge. I learned early on in the experimenting process that the electrolyte solution always discolors the wood after the electricity has been applied. It doesn't have the same effect without the electricity, so I can't just go back and apply more around the edges after the burning. In this case I kinda like the effect, so I don't mind it so much, but it's something to keep in mind. The other thing to take away from this is that the patterns got better as I went along. In the picture above, the top piece was done first, and they continue down in chronological order. I did the first coat of electrolyte on all of them at the same time, and then went back and did the second coat immediately before burning. This means that the pieces towards the bottom had longer for the first coat to soak in than the top pieces. This seems to have resulted in a better burn pattern, but also a deeper discoloration from the electrolyte solution. So it seems to be a trade-off, but the main takeaway is that on harder woods, it is better to give it a little more time to let the first coat of electrolyte solution soak in thoroughly before applying the second coat and burning.
OK, so now the burning is done. Time to put the machine back on the shelf and finish up the project. I needed some sort of legs or base to hold the mahogany up high enough for the tealights fit down through the holes. I had a couple of ebony turning blanks that I had purchased because they were on sale, and I think the black color of ebony will go great with the mahogany. After squaring, cutting, and drilling the ebony, the only thing left is to add a little polyurethane and do the final assembly.
Typically I would spray-finish this type of project with lacquer or something similar, but I was out of lacquer and I had some polyurethane-type finish lying around. Since I had never experimented with spraying this particular finish I decided to brush it on... big mistake. Between the dry-time, the sanding, and the 3-4 re-coats the finishing took forever. A weekend to build, a week to finish. It's time to go get some more lacquer.
And here we have the finished product. I think they turned out well, and they gave me a chance to play with my Lichtenberg machine again, so all-in-all I'm very pleased with this project.