Don't try this at home!
These plans were discovered by cigar box guitar builder and researcher, John "Reddog" McNair. I'm not sure whether to thank him for the discovery or scold him for digging up such a dangerous project!
In the directions of this 1919 article, readers are advised to hook up batteries and a rheostat to a single string which heats it, lowering the tension. The guitar is played by heating and cooling the string while strumming it at the same time.
This brings new meaning HOT ROD!
Ha! I laugh at danger! For the intrepid, this guitar has obvious utility.
Wear heat-resistant gloves, and use nichrome strings. This is the perfect instrument for outdoor restaurant troubadours during winter lockdowns. Keeps the fingers nice and warm, despite wind chill temperatures of 15 or so.
For an “instant light show,” the battery can ignite sparklers. (Check local fire laws concerning the use of fireworks inside tent restaurants. Dispensation for some types of pyrotechnic devices is available. If they may be useful for arson by anarchists or looters, a coronavirus permit is available.)
Between concerts, the talent can heat up a hotdog on the strings.