Here’s a fun project: Pop open an old microwave oven and scavenge the high-voltage transformer powering the cavity magnetron vacuum tube. Then use it to make yourself a Lichtenberg generator. But be sure there’s someone nearby to call an ambulance.
Lichtenberg generators are used to create art and abstract 
objects by burning fractal patterns into various materials such as wood and acrylic. They also have a propensity to kill and maim people. The Canadian Electrical Safety Authority recently reported two incidents where a Lichtenberg generator made with microwave oven transformers killed the operator and another where the user was only saved by the quick thinking of a bystander who administered CPR. In that case, the surviving user merely had to contend with severe third-degree burns.
It appears that many of these generators are homemade based on steps outlined in YouTube videos. These things generally look as dangerous as they are, consisting of not much more than the 2-kV oven transformer and a few dangling wires.
And there are numerous online videos showing exactly how to disassemble microwave ovens, though one often sees warnings not to take apart these appliances because they contain toxic materials and lingering high voltage. The hazardous material is actually beryllium mixed in the ceramic that is part of the magnetron tube. Beryllium is a notorious carcinogen when inhaled. So those who are of a mind to attempt this disassembly should never cut, grind, or otherwise mess with the ceramic components in the magnetron tube. (Some YouTube oven disassembly videos point this out. Others do not.)
The Canadian ESA also says you can find generators built this way being sold as commercial products, often in kit form. The problem with at least some of these kits is the aggressive marketing tactics being used to sell them. Their packaging indicates they are built with approved and certified components, but the complete generator has never been evaluated by any safety standards organization, says the ESA.
You might think that serious woodworking hobbyists would be sympathetic to shenanigans involving Lichtenberg patterns. Not so. The American Association of Woodturners, whose main tool of choice is the lathe, issued a statement in 2017 condemning fractal burning. “The process known as Fractal Burning is prohibited from being used in any AAW-sponsored events, including regional and national symposia, and that AAW-chartered chapters are strongly urged to refrain from demonstrating or featuring the process in chapter events…..The risks from Lichtenberg burning…. are largely hidden and the standards for personal protection poorly understood. Incorrect assumptions can easily lead to injury or death,” said the organization in its statement.
For those interested in creating Lichtenberg patterns without risking a lethal incident, there are alternatives. Hobbyist technology publications such as Popular Science describe a less dangerous method that involves creating Lichtenberg figures in dust using photocopier toner and a Van de Graaff generator (or even static electricity generated by shag carpeting).
The result may not be as impressive as the tentacle-like patterns transformer-powered do-it-yourself generators produce, but they are much less likely to result in the operator ending up on the Darwin Award list.
