Hydroformed exhausts. Expansion chambers and Megaphones

[Billy Golightly]

Always wondered how they did this, I use to think they were just stamped out and welded together but I now see I was wrong! http://www.eurospares.com/frame8.htm and this one too: http://www.two-stroke-addicts.freese.../hydropipe.htm

[Youngrasher]

Thanks, Its great to learn little tricks like this.

[Bryan Raffa]

Thats cool.. I have seen it done with just air

[SWIGIN]

thats pretty cool

[TRITecate350]

About 8 years ago, I toured Rick Ritter's shop (RCR) and he hydroforms his polaris pipe. He had stacks of pipe sheets cut out from a cnc plasma. He used a powerwasher to supply the presure needed to form the pipe. Then with the water drained, he would pressure the pipe with air and would heat the seam with a torch and it into shape. Then grind down all the seams and reweld them.

[RacerRichie]

cool
same here seen it done with air before but not water.

[Billy Golightly]

Whew, I'd be scared to use air. If one ever popped, it'd be just like a balloon but instead with sheet metal for shrapnel I dont know the exact physics behind it, but from what I was reading the reasoning for using water was because if there is a leak or something, all the pressure drops instantly and the power/force is dissipated a lot safer then if it was just compressed air. I've gotta try it someday though, I bet it works extremely well.

[Aka_am]

wow, someone should start making new custom pipes!

[gotcams?]

Hmmmmm.....I wonder if that technique can be applied to making a gas tank. I'm thinking the seams wouldn't be strong enough to hold that much pressure. An exhaust could, I'm going to give it a shot. Also might want to braze over the welds, might make it safer because brazing is typically used in raditors and repairing hydraulic lines. A weld will hold the metal together with a relative of 60k psi and the braze over that will stop leaks and give it added advantage. Only danger is the metal giving and not the weld, IMO.

But very, very cool!

[jeffatc250r]

Very interesting read. I never gave it much thought until this. Thanks for sharing!

[NOS_350X]

hmmm intresting, but every pipe ive ever see is eather a coned sectional or stamped pipe. Never seen one anything close to those

[Billy Golightly]

Actually this is how the ones that look like their stamped are made. The only ones that are truley stamped are the OEM ones.

[Daddio]

Whew, I'd be scared to use air. If one ever popped, it'd be just like a balloon but instead with sheet metal for shrapnel I dont know the exact physics behind it, but from what I was reading the reasoning for using water was because if there is a leak or something, all the pressure drops instantly and the power/force is dissipated a lot safer then if it was just compressed air. I've gotta try it someday though, I bet it works extremely well.

I'm not sure about the physics either but I do know that water can't be compressed like air.

[tri-z_250R]

I'm not sure about the physics either but I do know that water can't be compressed like air.

If I were to take a guess, it would be that they probably heat the steel to a certain temperature to make a easier to work with, and then they pump water in with incredible force before the steel gets a chance to cool down. It seems strange to me that water could do that.... maybe the water pump just keeps forcing water in until desired shape? They might even have to give it alittle motivation with a ?

[NOS_350X]

Actually this is how the ones that look like their stamped are made. The only ones that are truley stamped are the OEM ones.

I know esr gets there stamps from a company in nor cal, the come curved. From what ive herd. Almost all 2 stroke pipe makers go through them, They give these guys a pipe, they make a mold off of it and make stamps to fit around the mold.