They’re ridiculously easy to forge with a hammer.
Someone ?John Cogswell? did a really good chapter on forging in the
Penland book, and he covers mobius twists. Takes all of about 5
minutes. (My copy’s still in a box somewhere, or I’d tell you for
The gist of it is:
Get heavy wire. Bend into “U” shape. Tap sides of the bend of the “U"
more-or-less together with mallet. Lay it down on the anvil, and use
a broad crosspeen hammer to forge across the bend in the “U”. (the
"U” is laying down with both wires flat on the anvil) Place the
crosspeen such that it crosses both wires at right angles. Forge a
taper into the “U” section, so that the “U” gets thinner and longer.
Reduce the thickness by somewhere between 1/3 and 1/2.
Anneal. Now grab one leg of the “U” in each hand, and put your
thumbs on opposite sides of the “U”. Pull open like a wishbone. Use
your thumbs to support the crest of the “U” as you pull it open. Pull
the legs open until they’re back in-line with themselves as wire
again, and you should have a nice mobius twist in the middle of the
wire, to do with as you wish.
The variables of how closely together you squish the “U” at the
start, and how much you forge it down control what it ends up looking
like. I’d suggest playing around in 12gage copper first, to get a
sense of how it works.
If you really want to mess with people’s heads, instead of a “U”, do
a several "S"s zigzagging back and forth, forge out all the bends,
then open them up.