Topic: High Temp Bondo

[Ernest]

I picked up a 4 to 1 exhaust the other day.  It's pretty solid but has some bad surface rust on the inner header pipes and a couple dings on one pipe right where it bends.

I think I'll just sandblast and spray it with VHT black but I'm not sure what to use to fill in the dent.

will JB weld withstand the temp?

[Geeto67]

Jb might, but the proper way to fix it is to either:

- Cut that section of the pipe out and either fix it from the inside or graft in a new section, or

- You can use a slide hammer to pull the majority of the dent out, then fill in and grind down the area with welding rod (or just skip to fill and grind if they are small).

I think the reason you see so many mashed pipes on bikes is that there really isn't any good way to fix what you are talking about.

[merc2dogs]

JB weld melts/softens somewhere around 600f somewhere.
 You can purchase 'muffler mend' at auto parts that handles high temps. Some is like plaster and coarse surfaced, other type has a grey color with a fairly smooth and sandable surface.
 No idea how either holds up with paint.

 Depending on the depth, you may be able to braze a soft easily filed block in place then smooth it off for appearance.

Ken.

[squirley]

May be a little of the bondo topic, but to fix dents I drill a small hole on the opposite side of the pipe and insert a dowel and knock if out. Then fill the small hole in with weld.

[merc2dogs]

 Another effective way for some dents is to weld a large steel bearing that just fits in the pipe to a rod and force it past the dent, tapping on the dent with a body hammer to smooth it en-passant.
 with a slight bend in the rod you can go quite a way up the curves.

Ken.

[jason teamshralp]

wrap 'em up with exhaust tape. if your into that look.