Thanks for all the replies to my query about how to bend some tubing. I got
a bunch of private replies, so I'm just going to summarize all the responses
in case someone needs to search for it in some future archive.
First off, the question was:
> I'm looking for some help with bending tubing. I'm trying to make something
> which will require some sharp successive 90 degree bends in tubing.
> I will be using some tubing ~1-1.5" o.d. (undecided) 1/16"-1/8" thick.
> The two 90 degree bends will be about 3" apart, and perpendicular to each
> other. I would also distort the tubing as little as possible.
> I understand a mandrel bender would be the best route, but I don't happen
> to have one in my garage... The only thing I can think of doing is to
> clamp down two pieces of heavy rod in my vise, heat the tubing to cherry-red
> with an oxy-act torch, and then bend it using the rod. But I think this
> will seriously distort the tubing.
The reason why I want to do this was to form a brushguard for my truck (hence
the heavy gauge/large diameter tubing); those light assemblies were getting
expensive... Since I already a one of those tube bumpers, I wanted a tubular
grille guard to match it appearance wise; this ruled out welded joints.
The replies fell into 3 groups:
1) Cap the ends of the tubing and pack it with sand; the sand will help prevent
the tube from collapsing. An alternative approach would be to use a very
heavy spring in lieu of the sand. With the sand approach, weld some plate
to the ends to cap it, but leave a hole to allow any steam to escape. The
sand must be packed as tightly as possible. Someone mentioned simply even
tape might work. There were also suggestions on using lead and and water
rather than sand.
2) Take it to an exhaust shop or commerical electrical contractor and have
them do it.
3) Buy a mandrel bender from a source like Harbor Freight and have at it.
There you go! Thanks for the advice guys!