Steel treatment under sprayed insulation?

What treatment or coating (if any) should be applied to the inside of a steel hull before applying sprayed foam (PUR or PIR) insulation?

Thanks

 

Zinc Chromate primer or hot Zinc flame spray. Make sure you use the "closed cell" version of the product and you need a really, really, clean surface; think ethanol wash.

 

I've done a few that were blast media followed with direct application of closed cell poly urea. It was blast, heavy acetone clean, apply foam. Know of several that held up well to that for decades. Had one heavy glassed fish holds that had surface broken over the shaft alley from non fish freight. Got water ingress and started to cause issues. Was about 19 and given the task of stripping the existing foam..... where it had cracks and ingress it came up fine. Sides and overhead were brutal labor to strip and it was about 20 year old foam direct to previously blasted steel. Surprised me how good the steel looked under that foam.

A local boat had a big hold project foamed this year, it was blasted then epoxy coated and then foamed.

I'd talk to the foam supplier and ask, guessing they will have a pretty good idea of compatibility.

 

Many thanks gentlemen that's very helpful.
Cheers TT