Hmm, power coating sounds good idea but transport could be a problem for the finished frame. I suppose if I drilled and tapped all the holes first I could get the pieces coated individually.

I'd come to the conclusion that it must be a protective coating of some kind. It was a messy job getting it off but I'm pretty sure the paint finish will be better without it and there was some rust that needed removing anyway. I think next time I'll try just spraying over the top of it first.

Time to starting googling for spray primer I think.