RB wrote:

The biggest problem with sweating joints is not having sufficient heat.
I don't mean flame temperature I mean heat (energy.) The thermal mass
of a goods sized ball valve is substantial and a small propane torch is
not going to be able to raise the temperature of the valve quickly
enough to avoid also overheating and damaging the ball seals. A good
MAPP torch is the minimum I'd use. Most times I reach for my acetylene
torch for ball valves.

Ditto on the MAPP gas, many torches these days will take both gasses.

I got a fancy (T501) Bernzomatic torch, which does a real good job of
heating up joints, like 2x faster than the plain torch, which worked
fine till I dropped and broke it. Something about the swirl tip. Instant
on/off is a nice thing to have as well.