downpipe - cracked?
 

is it common for stainless steel downpipes to crack over time?

if so what causes this..

No, it most certainly is NOT common, in fact I've never heard of a single case of this happening in 5 years here.

In general, if one did crack, it could be the result of a bad weld, or excessive stress due to misalignment. Heat-shield wrapping could make it more susceptable to cracking due to the increased temperature in the metal.

Dave

Was it a mandrel bent DP? I would think the only weak points in it could be the welds at the flanges. I'd like to see a pic if you have one.

Just dont get that cheap ebay dp.

It's possible, although it would be the first time I've heard of it.

The strength of a weld can vary widely based on how it was done, what weld wire was used, base material, voids, cracks, cleanliness, corrosion, etc, etc. No doubt, a cheap downpipe is more likely to have crap welds. In most cases, the downpipe carries very little stress, but with the right combination of things it could break them. I would take it up with the original vendor and send them photos of the break.

Most good vendors of welded products will usually step forward and supply a replacement. It seems in this case like it would be impossibly difficult to break a good weld. This case almost certainly hinges on a bad weld.

Dave

its not on any of the welds actually, what i found are on the outer walls of the pipe. it was wrapped. the cracks seem to have started from the outside, and are still pretty superficial as far as i can tell.

I wonder if it's chloride- related. Heat wrapping can capture road / sea salt, and that will attack 304 noticeably.

Dave