Here's a toughie

[LatakiaLover]

The problem is when using Lucite for thick, short, bent stems, similar to the one in the pic. Heat that short chunk of plastic enough to get a smooth bend, and the tenon is ALSO hot enough to bend.

Lost a stem this morning from exactly that. All went normally and smoothly, but when eyeballing the final result I noticed the face of stem and shank were no longer in parallel planes. Gappage at the top, when I'd started light-tight.

Before making another, I thought I'd bounce it off you guys. The more you think about it, the trickier it gets... the softening point for Lucite is very sharp---just a few degrees---so getting thick area hot enough WITHOUT getting the low-mass areas on each side of it hot as well, the bite zone and tenon, is double-tough.

Because Lucite will shrink all over when heated that much a second time, you only get one shot at it, too.

(The pipe in the pic is vulcanite. Come to think of it, I can't remember ever seeing a Lucite-stemmed bulky Author/Rhodesian. Hmmm... )

[hazmat]

LL.. I use a hot sand box to bend stems. This might work for your situation, perhaps. You would be able to put the stem into the hot sand bit end first up to just beyond the area you want to bend(I'm behind a firewall so I can't see the picture, I'm assuming there's enough stem to do it this way) and allow the tenon end of the stem to be out of the hot sand. It might keep that end from getting too hot and going out of true on you. Maybe...??

[JHowell]

The thickness of the stem is a compounding factor. If the tenon is long enough, I'd hold it by the tenon in a lathe (collets really shine for something like this), leaving just enough gap to kiss the shoulder with a parting tool. I doubt the gap is more than a couple thou. Then you might have to put it on a mandrel to shorten the tenon however much you took off the shoulder, but beats making a new one.

[edboyce]

You might try using a heat sink putty like plumbers use. It was intended to protect valve packing from getting melted when the torch is applied to the pipe.

[LatakiaLover]

You might try using a heat sink putty like plumbers use. It was intended to protect valve packing from getting melted when the torch is applied to the pipe.

That was my first thought, actually, then figured a cylinder's heat transfer wasn't similar enough to a tube's to work.

Thinking it through, again, since the temp threshhold of Lucite is so sharp, a drgree or three might be all it takes.

Thanks for reminding me, Ed. I'll definitely try it. Why not? It'll either work or it won't.