Pipe Bending

[MidnightBlade]

How can I bend exhaust pipe without heavily creasing it? The 90* I put on my truk for a side pipe has 3 huge creases and is squished to about 2 1/2" on the bend instead of 3", I'm fine with alot of small creases.
Is filling the pipe with sand a myth or does it actually work?

 

[Diesel_brad]

Unless you have a pipe bender with the dies, you will kink the pipe

 

[93_444idi]

just use some flex pipe. sounds half assed but it works fine, its cheap, and leaves no kinks.

i had to move a section of my exhaust when i swapped transmissions because the crossmember was in the way. just used some flex pipe to bend around it. doesn't hurt the sound and only helps performance because there is no crease. oreilleys has 3" flex pipe, that's where i got mine. like $8

 

[Dieselcrawler]

nbut remeber, that flex pipe is not pa legal.

 

[MidnightBlade]

My inpection station is Lick Em' N' Stick Em', unless the cop really wants to go out of his way to bust me, I think we'd be all good.

 

[trapper]

i talked to a exhaust shop here for 4 inch pipe and they told me they would cut it bend it and re weld it

 

[93_444idi]

if not flex-pipe, you can buy mandrel bends from summit. little pricey, but no kinks and not illegal.

 

[MidnightBlade]

i talked to a exhaust shop here for 4 inch pipe and they told me they would cut it bend it and re weld it

I am thinking of that too, alot of extra effort when we have access to a pipe bender though

93444idi-I don't mind alot of small kinks but I hate big kinks

 

[sassyrel]

sand in the pipe works,,for bending stainless pipe in a pipe bender....but freehanding pipe and sand??? not sure it would work!!!!!

 

[MidnightBlade]

Not freehanding, we have a pipe bender

 

[sassyrel]

Not freehanding, we have a pipe bender

i DO know,,from having run one i the past,,at bros station,,sand works!!!!

 

[jam0o0]

this might seem nit-picky but it makes a difference.

exhaust is TUBING. tubing is measured and named by the OD.

PIPE is named by it's nominal (think not real) size.

example: 1.75x.125 tubing is closest to 1.25 sch 40 pipe.

you can not bend tubing in a pipe die and expect it to come out smooth.

there is a minimum bend radius for most pipes/tubes based on wall thickness. thin wall, large diameter pipe/tube has the largest minimum bend radius. so if you want little bends in 3" exhaust tubing it's not gunna happen unless you have the double mandrel multi thousand$$ machines.

example: the smallest bend radius you can usually get 1.75x.125 tubing is 5" on a standard rotary draw bender.

 

[DeepRoots]

summit sells elbows.
Buy one (or two) weld them in place.

http://www.summitracing.com/search/?keyword=exhaust elbow&dds=1

 

[ocnorb]

summit sells elbows.
Buy one (or two) weld them in place.

http://www.summitracing.com/search/?keyword=exhaust elbow&dds=1

^^^^This is the answer^^^^

I've been buying mandrel J bends from summit for a while- I use the chop saw to cut the angle I want , then weld it all together. Put a 3" cat back on my CRD that way and it turned out great.

 

[jmac212]

We learned to bend pipe/tubing by hand with a torch and filling it with sand while in HT "A" school many years ago. I have the exact method in a book somewhere, but the short version is this: fill pipe/tube with sand and make sure it is tightly filled. Cap or plug both ends. Now lay out your bend using a MBR (minimum bend radius) of 4 times the radius. The bend can be made to a tighter radius, depending on ID, wall thickness, material etc... but is usually done with a machine. Graduate the length of your bend into 3/4 or 1 inch increments. You will need a length of tight fitting pipe to go over the tube to use as a cheater. Heat the first graduated area all the way around and then apply cheater pipe and bend. How many graduations and how many degrees to bend each one will have to be determined by the fabricator. An easy example would be a 90 degree bend over 9 inches is nine 1 inch graduations each bent 10 degrees. The results were pretty dang good, but it is time consuming. If you are into fabrication and metal work, give it a shot. There are some other alternatives that may suit your needs better though. I have never tried bending a sand filled pipe/tube in a bender. If you try this, let us know how it worked.