For those using, and having trouble with, the Giles style wax pens,
try replacing the primitive strip of tin can rubbing on a coil of
exposed wire with a real rheostat. Trot down to your local
electronic store, something a bit more advanced than the local Radio
Shack, and ask for a 50 watt, 1 Ohm rheostat. Replace the original
Giles’ primitive apparatus with something from the 20th century and
that part of your wax worker problems will be solved for years to
come. I replaced mine (with an Ohmite brand RJS1RO, model J -
$15.00 ?) about 10 years ago and it’s still giving me trouble free
performance. Now my only problem to deal with is operator error.