Tuesday, May 30, 2017

Experiments with Lichtenberg Figures on Hardwood

     In one of my earlier blog posts on Lichtenberg Figures I made the observation that they did not work well on hardwoods.  However, after continuing experimentation and my success with the mahogany tealight holders, I decided that I simply had not perfected the technique required for burning figures into hardwood.  When I finished the tealight holders I decided to do a little more experimentation before retiring the Lichtenberg machine back to the shelf.  I chose four species of wood: red oak, mahogany, ambrosia maple, and walnut.  I used two pieces of each species, and in an attempt to be as scientific as possible, I planed and cut all the pieces to the same dimensions, approximately 10" x 3-1/2" x 3/8".  For the electrolyte solution I used 1-1/3 tablespoons of baking soda to 1 cup of hot water.  It seems that the trick for getting hardwoods to work is to make sure that they are thoroughly saturated with electrolyte solution, so two coats are necessary before burning, and then additional coats are required throughout burning as the heat from the procedure dries out the wood.  I presoaked all of the pieces by brushing on a liberal amount of solution while avoiding the edges of the pieces.  I did the second coat of electrolyte immediately before burning, concentrating more solution around the area where the electrodes will connect.  In the video below you can see that in almost all instances the pieces will dry out around the electrodes first and will require constant re-wetting throughout the process.

     Now that all of the pieces are finished, it looks like red oak turned out the best (upper left in the picture below), followed by mahogany (upper right), then walnut (lower left), then maple (lower right) respectively.  By best I mean they had more detail, and less thick, deep burns.  This is subjective of course, and other people might be looking for a different effect.

     My hypothesis was that the harder the wood, the more detail would show up, and the softer the wood, the deeper and thicker the burn would be.  While this seems to be generally true (pine and MDF burn thicker and deeper with less detail than hardwoods), between hardwoods there seems to be other factors effecting the pattern.  Confirming my theory, Red Oak is the hardest of the woods I tested, and it did have the most detail.  Maple is the softest, consequently having the least detail.  Walnut, however, is harder than the Mahogany by a significant degree, but it burned decisively deeper lines with less detail than the Mahogany.  Further experimentation along with additional research into the characteristics of the woods will be necessary to determine what factors other than hardness effect the burn patterns on various species of wood.

     Now that the experiment is over, and the Lichtenberg machine has been relegated to it's spot on the shelf, I am once again left with a bunch of wood panels with neat designs but no real purpose.  This time I decided to do something with them.  I was not overly impressed with the Maple, so I set it aside and proceeded to finish the other panels with four coats of polyurethane.  With some brass hooks and eyelets, and a length of brass chain, I connected the panels together to create a simple wall hanging.  I think it turned out nicely.

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