In article , wrote:

BTW, I intended to point out to the "close up the gap" faction that when
the fitting is heated, it will expand as does the pipe so the
differential expansion is essentially the same between the two mating
pieces--ergo, the gap doesn't actually close.

Right - but if the pipe is heated, and the fitting not heated (or heated less
than the pipe), then the gap *will* close (or at least shrink), and then
expand as the joint cools. That's not good.

--
Regards,
Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?