Sheet metal forming

[Alexander]

I was wondering if any of you have some equipment or experience shaping sheet metal. This exaust is off my scooter.
It works great the issue is the metal it was made from is very brittle. Unfortunately it cracked right at the end of the big gusset on the first 180 deg bend. I was thinking maybe I could use a small plate roll to recreate some of these shapes and either patch the pipe up or rebuild parts of the pipe. Im thinking the bends are hydroformed but i dont know.

 

[DPittman]

It looks like it was maybe welded already but that would be my first method of repair again if it were mine.

 

[Alexander]

My goal was to make it so it wouldent crack again. But yeah welding the crack will be part of that. Then im hoping there is some way to improve its strength.

 

[DPittman]

I think it is cracking likely because the gussets do not allow for the expansion and contraction of the metal as it gets hot and then cools.

 

[PeterT]

I've seen some homebrews in RC model applications ranging from works of art to Yeesh. Yes, compound curves like some of your section are probably hydro. The multi-segmented types look like pretty demanding TIG skills. Found this link with pics
http://opeforum.com/threads/pipe-building-theory.4830/

I ran a lot of tuned pipes on my pattern birds. The trick was you have to allow them to shrink & contract as mentioned. We used combinations of semi flexible silicone mount, or viton o-ring mid coupler at the header/pipe. If we locked down the whole exhaust assembly it will find a place to split. Usually a weld or tight header bend or bend the exhaust bolts. Maybe not your exact application by maybe similar. Also vehicles have vibration so that might be stressing it.