its a lot like jb weld but its not an epoxy i do powder coating we use this lab metal a lot we get it from a company called Fastenal its a little pricey but well worth it as long as the powder coater knows what they are doing i would get a hold of the powder coater you are going to use and see what they use but here is a link to the lab metal
http://www.fastenal.com/web/products/detail.ex?sku=0815227