Custom Metal Fire Pit Question

[Freiburger Welding]

Hey there. We make custom metal fire pit rings from 10 gauge steel and recently had a customer send me this photo. I am unsure what is occurring in this photo as I haven't seen anything like this before. Our fire pits are painted with Rustoleum high heat black spray paint. They are washed with acetone prior to painting. Customer has only had 2 fires in the ring. Any feedback would be appreciated.
Thanks!

 

[DPittman]

Looks to me like it simply got too hot and burnt the paint off. I imagine the customer had logs/coals up against that spot and it simply got too hot.

 

[CalgaryPT]

I've made my share of smokers and firepits, and used the exact same acetone to high heat paint treatment as you, with great results. Once I had a paint can that was over wintered (should have known better) in an uninsulated garage and it peeled after one season. The second incident (similar to yours, but a little different), I never figured out. But I suspect it was caused by an accelerant dumped into the fire. The people using the ring were kids and there were a lot of burn barrels around, so I think they had a more than casual relationship with fire.

That's the extent of my speculation. Best of luck. Let us know if you figure it out.

 

[CalgaryPT]

One last thought: did they by any chance use a Tiger Torch or propane torch to start it? I've seen people do that before too. Not sure of the end result, but I suspect that could do a number on even the high heat paint. Can't tell from the pics, but look for run away around the edges of the paint. If that exists, it's usually an indicator the paint was pushed back by a compressed gas flame—just like O/A will do if you cut a painted plate.