I need it for Exhausts as well. 0.7 to .9/1.0mm mild steel and StainlessSteel
Blimey, DIY hydroforming. That didn't look at all risky, did it.
There's some sort of manually operated pump that plumber's use for pressurising systems.
I've heard tale of people using those to do the job, the advantage being that if anything starts leaking, then you more or less instantly lose pressure as water isn't compressible.
Apparently about £8 a day to hire according to Dave the plumber....
That is exactly the one to use! you are better tig welding the sheet metal together as it is less porus, if you bring the edges up slightly it helps with the forming, also a little heat when you are applying pressure on difficult areas helps a lot.
A way of making a template if you have a sample pipe you are wanting to copy is cover the pipe in masking tape and then slice in half using a scalpol or sharp stanley blade.If you want to turn the pipe cut through when formed and twist untill you get the pipe clear of what you are trying to avoid.