Welding my expansion chamber, advise please

[nick20555]

so I got a question. The pipe on this 250r I bought is a sparks mx pipe and is apparently THE pipe to have on a 250r but mine is cracked real bad near one of the mounts and causing a severe exhaust leak. I can have it welded at work but I wanted to know if there is anything special about welding an expansion chamber? What about the potential flammable residue left behind in the exhaust ? Do I have to clean the inside of the pipe before it gets welded? If so, how? Surely one of you guys have welded an exhaust before and can guide me in the right direction.

 

[Larry's Shee]

Just clean area with wire wheel or Scotch Beige pad. Use paint thinner or laquer thinner for oil residue. DO NOT use brake cleaner for anything that is to be welded.
Might heat area of crack to burn oil off inside before.

It's not like you're welding on a gas tank, that's sketchy

 

[nick20555]

I just didn't know if the expansion chamber would act as a tank and hold fumes or something or possibly blow fire out the ends like a torch lol

 

[Larry's Shee]

Could mix some dish soap and water and swish it around in there.

 

[nick20555]

Not sure but I think I swooshed paint thinner around in my blaster pipe and then followed through with water and I was so scared that my pipe was gonna explode the first time I kicked it over because of the paint thinner lol

 

[Blaaster]

It is the seams inside a container that hold fluid where the fumes originate from.

As there are no seams it should be safe to weld after a good flushing.

 

[nick20555]

I splashed some paint thinner around in it, then a couple times with some car wash soapy water while I had it out for my blaster and then the next morning after it dried, I held a lighter to both ends and nothing happened. Hopefully its ready.

 

[Larry's Shee]

I've welded/soldered a few cycle has tanks. After washing/rinse I would stick the torch in the opening. Figured if it was going to blow, I didn't want it to be a surprise

 

[nick20555]

Here are some pictures of the pipe. The first is of the crack that needs welded. It walks around a previous weld that looks like was for putting the mount back on. This probably explains why it has a little bracket that it mounts to rather than directly to the frame. I'm going to see if I can grind it down so it isn't so raised and probably the reason for the crack.

The second is of the previous weld right at the main bend in the pipe. You can see how poor of a weld it is.

Third is just a picture that shows the dings in the pipe.

This just shows the condition that my pipe is in and the reason why I'm not too worried about it if the attempt to patch the crack in it isn't successful and destroys it. I probably need to get a new one at some point anyway.