DIY Exhaust tubing bender?

MikeWhitney · **Joined:** Wed Aug 20, 2003 9:15 pm **Posts:** 4724

I can't seem to find a straight answer to this on the internet anywhere...

Short of buying one of the $5000 exhaust bending machines you see at real exhaust shops, does anyone know of a $200 or less piece of equipment that will bend exhaust tubes for the DIYer?

My bends don't have to be fancy but I need to make sure that I'm not going to be cracking or completely crushing the tube. I was leaning towards the hydraylic HF one for $80 but their description says "will not bend exhaust tubes". WTF?

Anyone with first or second hand experience or recommendations?

Wes Eargle · **Joined:** Mon Oct 27, 2003 9:47 am **Posts:** 3683

Wouldn't it be cheaper to buy mandrel bends and weld up things yourself instead of bending the tubes?

MikeWhitney · **Joined:** Wed Aug 20, 2003 9:15 pm **Posts:** 4724

Wes Eargle wrote:

Wouldn't it be cheaper to buy mandrel bends and weld up things yourself instead of bending the tubes?

No

Ashraf Farrag · **Posted:** Mon Mar 26, 2007 5:37 pm

Mandrel benders are expensive for a reason. :roll:

Depending on the tubing size, it may be harder to get it bent - I think 3" is where fewer machines are capable of doing it, at least this was a few years ago dealing with an RX-7 exhaust.

If you know the exact dimensions, you could get someone to custom-bend it for you on one. I never priced it out, I'm not sure how expensive it would be.

Pipe benders as you pointed out, won't have the support inside the tube and will end up crushing it.

It is painful but I've done my fair share of cutting up pre-bent mandrel bends to make up an exhaust. That is the price to be paid for building it yourself. You also get to practice welding as a bonus...

If you do come up with a bending solution that is reasonable, I'd love to hear about it.

Regards,
--Ashraf

MikeWhitney · **Joined:** Wed Aug 20, 2003 9:15 pm **Posts:** 4724

Ashraf Farrag wrote:

Mandrel benders are expensive for a reason. :roll:

Depending on the tubing size, it may be harder to get it bent - I think 3" is where fewer machines are capable of doing it, at least this was a few years ago dealing with an RX-7 exhaust.

If you know the exact dimensions, you could get someone to custom-bend it for you on one. I never priced it out, I'm not sure how expensive it would be.

Pipe benders as you pointed out, won't have the support inside the tube and will end up crushing it.

It is painful but I've done my fair share of cutting up pre-bent mandrel bends to make up an exhaust. That is the price to be paid for building it yourself. You also get to practice welding as a bonus...

If you do come up with a bending solution that is reasonable, I'd love to hear about it.

Regards,
--Ashraf

If I was doing a header I'll use mandrel bends. For the pipe in question though, it's basically a straight pipe with two like 5 degree bends. Almost nothing.

I think I'm just going to slash-cut the pipe where I need a kink and reweld a corner in.

Todd Breakey · **Posted:** Mon Mar 26, 2007 8:25 pm

Hey Mike, would anything like this help?

http://search.harborfreight.com/cpisear ... ipe+bender

MikeWhitney · **Joined:** Wed Aug 20, 2003 9:15 pm **Posts:** 4724

Todd Breakey wrote:

Hey Mike, would anything like this help?

http://search.harborfreight.com/cpisear ... ipe+bender

Thanks Todd - That's exactly the one that I was planning to buy which says "does not work with exhaust pipe" or some such nonsense. I'm pretty sure it will put some really shallow bends in a 2.25" tube for me.

Charlie Guthrie · **Joined:** Thu Aug 28, 2003 8:14 pm **Posts:** 832

An old trick we used was to pack the tubing with damp sand. The sand if firmly packed supports the tube wall preventing buckling. I suspect using carolina clay might work as well. I would practice on a short piece before trashing a long piece.
On the other hand, I have had real good luck using the Mieneke Muffler shop on Capitol avenue near Peace street. They have tacked things back together for me and added tubing and a host of other home projects at a very reasonable price. Of course I haven't used them in a year or two and the old guy who managed the place may have retired. Unfortunately, the Meineke muffler within a couple of miles of my house is run by a complete SOB.
Charlie G

Keith Vail · **Posted:** Mon Mar 26, 2007 10:21 pm

My dad has one of those. I would not recommend using it on exhaust tubing as it will probably collapse. Those benders are designed for thicker wall tubing than what is used on exhausts and those real expensive hydralic benders actually grip the outside of the pipe and pull on it while the die on the inside pushes it into shape. I have experience with both machines and they work very differently. I don't want you to spend money on that just to find out it won't bend an exhaust pipe much at all.

ChuckNelson · **Posted:** Mon Mar 26, 2007 10:37 pm

This is just what I have heard. The big problem with the cheap Harbor/Northern benders is that the mandrels are not the correct size for certain pipes and that causes the problems. You can get mandrels machined to match you pipe and that will help.

Personally, I think it will not matter to much for such a slight bend.

I would still consider prebents. With such a shallow angle you could get what you want out of a single U and you would get some good cutting/welding prep and practice.

Ashraf Farrag · **Posted:** Mon Mar 26, 2007 11:52 pm

MikeWhitney wrote:

If I was doing a header I'll use mandrel bends. For the pipe in question though, it's basically a straight pipe with two like 5 degree bends. Almost nothing.

I think I'm just going to slash-cut the pipe where I need a kink and reweld a corner in.

The first piece of exhaust work I did...I didn't use mandrel bends. I just kept cutting straight pipe at angles to make a bend, mostly because I thought I didn't have enough room to get a bend in there.

For a 5 degree bend, you'll end up with a bit of a oval character at the end of the tubing that you cut but it should be close enough that you can get the ends to mate or just use the bender for a 5 degree. They are probably equal solutions (i.e. not perfect/a compromise).

For a larger bend, I got to thinking and came up with the same suggestion that Charlie had: using sand...I recall seeing it somewhere else before but I can't put my finger on it...

Regards,
--Ashraf

George Bright · **Posted:** Tue Mar 27, 2007 4:21 pm

He He

Pound sand :lol:

MikeWhitney · **Joined:** Wed Aug 20, 2003 9:15 pm **Posts:** 4724

Good comments and advice everyone, thanks for the input.

I think I've settled on the following:

1. When possible for really shallow bends just slashcut the pipe and reweld. I think the current midpipe project I'm working on will work fine for this.

2. Buy the HF crush bender just because I can. Maybe use it when I can't do #1

3. Order up some mandrel bends to keep around. I just got a couple of "J-hook" bends from theflangeman for like $11 each for when I get ambitious about making a larger diameter equal-length header for the Subaru.

Should be a fun summer of exhaust projects!

Scott Johnson · **Posted:** Wed Mar 28, 2007 6:37 am

What about an oxy acetylene torch and a baseball bat.

The bat is a lever, the torch it so heat the metal cherry hot...

Ron Spencer · **Posted:** Thu Mar 29, 2007 7:15 pm

Heck just go open exhaust. Will keep the course workers from falling asleep.

R

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