I've tried that years ago Joe. That idea has been around for
many years and it doesn't work without heat because the sand
really won't keep the inner and outer radius from collapsing
and forcing the edges out. The best example I can think of is
to fill a balloon up with sand and observe how it will conform
to any shape the balloon is squeezed to, same thing happens to
a pipe. If the pipe is heated to about 1500°F then the sand
will minimize the distortion somewhat. But that certainly isn't
practical for bending an exhaust pipe and I would think it
would be difficult to keep from getting thin spots in the tube.
I have however filled short header pipes with Cerrobend (Woods
Metal)then made the bend with the pipe shoes. That took a lot
of filler which is very expensive. Here's a partial view of
those headers which are type 421 Stainless:
http://www.pbase.com/dennygraham/image/121521109To get a decent bend without collapsing the tube you have to
have a follower on the die that keeps the sides from expanding.
Even though these dies sets do a pretty good job of preventing
ovalization you may still get some wrinkling of the inner
radius. Those beautiful uniform tight bends you see in the
header kits call for very sophisticated tooling using a bend
die, follower or roller die usually a linked ball mandrel and
wiper dies.
I have the ability now to bend the tail pipes and I'm waiting
for an answer form Greenlee on a 2" die set for my 782 bender.
I've also been in touch with Mittler Bros. for a 2" die set that
will work in my Greenlee bender.
So, many or should I say most are saying, why in the world does
this idiot want to bend his own pipes???? #1 I've got the
bender. #2 what I well save on having pipes bent for a couple
of trucks will pay for the 2" die set that I'm missing from the
782 set of dies. #3 Is simply that I get a boost out of doing
things my self and doing them the way I want them done. Guess
you could say I'm a control freak.
DG
