Filling Exhaust Pipe With H2O, Then Freezing To Mandrel Bend ?

Has anyone one ever filled exhaust pipe with water, plugging both ends before freezing to accomplish mandrel bends using a regular bench tubbing bender? I have heard of the sand method and seen the end result on old modified / oval dirt track cars, however; the mandrel bends were not uniform through the radius of the bend.

Anyone ever use the frozen H2O method and how is the finished product? Would this method work for custom headers?

Thanks....

 

no water will expand when frozen.
buy mandrel u bends cut and weld them together.

 

Send method works well. If there were kinks, it was b/c the metal wasn't heated evenly.

 

I do not want to purchase 'J' bends etc. and weld them together !! We are currently speaking to a shop who has a mandrel bender, however; an old oval dirt track racer in our area just built custom headers using the frozen water method. I have been told the headers turned out great, however; the fellow has since sold the car to fund his hot rod project.

What are the trade secrets with the sand method?

Thanks....

 

When the water turns to ice it expands and the tubing will burst. This is what tears up the roads in the winter and splits the water pipes in unheated areas.

 

I realize what happens to water when it freezes, however; this was a civil engineer who used the frozen water method, so I am told as I have not been able to contact him today, to make his headers on his dirt track racer....

 

1. Fill pipe with sand
2. Cap ends
3. Heat
4. Bend
5. Remove sand

 

Make sure the sand has no moisture in it.

 

I've also done the sand method and it works quite well. Good luck - Flatheaded

 

why not fill with water & cap , no freeze , then bend , I wonder ???

 

Instead of just straight frozen water, maybe something like pycrete? Half sawdust half water frozen together. Way stronger and more stable than ice alone. During WWII they tossed around the idea of making a ship outta the stuff. Was strong as Hell. Just thinkin out loud here. I'll stop now.

 

Well, if you got the correct amount in there it would not burst the pipe but if you left the ends capped to keep the water in and then heated it the water could turn to steam and then you would really burst the pipe possibly killing you ar someone else. There would be a fine line to doing this and I also dont see you bending pipe that is solid with ice anyhow.This sounds like a dangerous idea to me.

 

I take it you're going to try and bend the filled pipe while it's still frozen? Seems like alot of wasted time and effort, waiting for the piece to freeze until you bend it. And don't forget, ice doesn't bend. It's a solid. It breaks, and the metal will kink where the breaks are.

 

The reason the flow wasn't smooth is because there was no mandrel ball being pulled through the pipe to reshape it. If you were looking at a dual wall pipe, I could understand the ice thing but I'm not convinced it will work all that well frozen on a diameter that large.

Try steel shot, pack it in good with a wooden mallet, weld the ends shut and bend it. No reason to heat it up, you aren't going to get to plastic deformation point anyway so why bother?

Better yet, find someone with a mandrel bender and go for it. Are you Ontario CANADA or Ontario California?

 

FWIW- Low melting point alloys such as Cerrobend have been used for tube bending in the past- here's some links: http://en.wikipedia.org/wiki/Cerrobend http://www.rotometals.com/ http://www.hitechalloys.com/

 

That's because they were "sandrel", not "mandrel", bends.

 

I saw a story about makin' trumpets on John Ratzenburgers "Made In America" on the Travel Channel. They pluged one end of the trumpet,when it still looked like a long *** funnel, with a secret liquid put it in horizonal freezer lookin' thing for a secret amount of time then pulled it out and bent it. Have fun,Smokey

 

Freezing a pipe full of water should take about 3 minutes tonight, in Ontario.

Just cap one end.

Don't stick your tongue on it.

 

Ron Covell explains and demonstrates the "Sand Bending Technique" in one of his video's....I think it's the one ***led "Working With Tubing". Anyways, I have done this before.
1--You need to have the sand dry and without any moisture in it, I snuck into the kitchen one time and baked it for a couple minutes!
2--Cap one end of the tube you are using with a peice of s**** metal, and weld.
3--pour sand into the tube and bang it on a 2x4 on the ground to compress the sand. Continue this process until your tube is completely filled. You want the sand to be as compressed as possible.
4--weld on another cap to seal all the sand inside the tube.
5--get a peice of angle iron and lay the tube inside. (this helps distribute the heat)
6--use a rosebud tip on your oxy-acytalene torch and evenly heat the area to be bent.
7--quickly insert the tube into a jig that you have already made to bend the tube around....(a s**** peice of bar stock clamped to the table, ect.)

 

That's what I was thinkin' cap one end, fill with water, freeze then cap the other end and bend. I'm not saying it'll work but looks like that would solve the bursting pipe part of it.

 

They taught the sand trick in Navy HT A school. The ice trick is lame. You would likely need hydraulics regardless just to bend the damn pipe. When I was a kid I filled an enduro tank with water and hoped it would pop out the dents while I was sleeping. Hell no it didn't work. I just had a tank full of ice.

 

I was wondering about the heating part of it. It never occurred to me that you WOULDN'T be using a hydraulic bender! I guess I've been in the exhaust industry too long...

 

The topic at question here is for EXAUST TUBEING. I should state that I've only used the sand technique for thicker wall round tubing....but I would think with care you could apply the theory to thin wall exaust tube.

 

Any one realise that liquid under pressure freezes at a lower temp? Avoid capping both ends or it will either take forever to freeze or it simply wont.
If you want a superior finish with half the trouble use sand. There is a reason it is MUCH more widely used!

 

Thanks for all the ***istance....

 

Water expands into steam at the rate of 1000-1 . you will effectively have a STEAM BOMB!

 

Freeze The Exhaust Pipe, then bend. I was not going to use heat!

 

Nope, it isn't going to work. Ice is a crystalene structure, and as pointed out, it will shatter in random patterns as the pipe is bent, and the pipe will still collapse. The sand business is questionable at best---it works to some extent with heavy wall pipe but not worth a **** on thinwall stuff like exhaust tubing. And forget "pulling a ball bearing thru it". --Mandrel bending is done with a whole series of bearings or "slugs" in the pipe before it is bent.--that prevents the pipe from collapsing in the first place. After the pipe has already collapsed, there is no way in Hell that you will be able to "pull a bearing thru it" to "uncollapse" it. The low melting temp alloy in the pipe would work to prevent it from collapsing, but you would have to fill the entire pipe to ensure that there was some alloy right where the bend was going to occur.

 

Ever try to bend an icicle ?

 

why don't you just give it a try? if you fail you are not out much

take pictures and post what happened here