Re: would this contaminate my welds?
 

With a little bit of ingenuity, and patience, you wouldn't need a faggot ass "solution" for anything, because there wouldn't be an issue... But if it works, to each their own I suppose :X

Re: would this contaminate my welds?
 

ive got an idea.

instead of putting the foam on the inside and giving yourself the added problem of getting it out, why dont you just put the foam
on the outside and make a mold. cut the mold in half and lay the pipe inside the mold tack it in the mold and simply lift it out.
if you wanted to get even more intuitive you could wrap that foam mold in fiberglass. done.