Heard about a buddy who skipped pre-heat on a big pressure vessel repair. The thing split like a cheap seam the first time they fired it up, exactly like robertb30 said about the temp difference. He learned the hard way that code is just a suggestion for staying out of real trouble.

My buddy had a similar problem with his plaster mix always coming out lumpy. He started mixing the powder in a separate bucket with a drill paddle before it ever touched the mortar board. It added one step but saved him a ton of time and elbow grease trying to smooth it out later. The consistency was night and day, and he said it went on like butter. It's funny how one small change to the routine can make such a big difference.

Ever tried asking for that discount and gotten a flat no?