I'm kinda thinking of making a model airplane muffler or two. These
days the things are generally cast in one piece -- but that isn't going
to work for a one-off.

These things have a header that comes off of the engine, then goes into
a tube-shaped expansion chamber. See some examples he
http://www.mecoa.com/kb/aero/aircraft.htm

I'm thinking that I can fabricate one of these with a machined header,
machined ends, and a section of tube. But it'll all be aluminum, so how
to join the pieces?

I'm assuming that JB weld won't take the heat and will just fall off.
But I'm ready to be corrected.

I don't have a TIG welder, or I'd just select TIGable materials and be
happy.

I do have an oxy-acetylene set, and I certainly know how to solder.

So -- will aluminum brazing work on this? What sort of selection do I
have as far as difficulty vs. results goes? Brands to look for? Avoid?
Places to get stuff? I'd like something that's going to be as strong
(or nearly so) as the parent material and that can be done on a welding
bench with a torch and a vise.

TIA.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html