RupertW
Well-known member
I would have thought not very far before it's cool but it would be a good experiment for PBO to do
But it doesn't have to be hot to sink into gel coat - my worst rust staining on gel coat was when polishing some very rust stanchion posts with wire wool (idiot, idiot, idiot). None of the wire wool strands were hot but they all melted into the gel coat before I spotted them the next morning and the stains were way into the gel coat and couldn't be T-cut out. It needed a lot of goes of acid cleaner before they finally faded. Add iron/steel tiny fragments plus moisture to gel coat and let it sink right in.