Since my last post about molds I have had some feedback regarding stainless steel molds from other glass artists.
Drewjaeger says: I use stainless all the time and have never had anything crack. I just heat very slowly on the way up. And for slumping inside I don't use anything very steep. I'd say 75% of my mold collection is stainless and most of that came from thrift stores for about a dollar or less.
Nivenglassoriginals says: Regarding the stainless molds - that's what I use also. Hadn't heard about the cracking problem before - ignorance is bliss I guess - I've had no problems - touch wood. I sand the stainless really well - really well - and then apply the primer. The more you sand, the easier it is for the primer to stick. If I'm applying the primer and it is just washing off, I know I haven't sanded enough. So I sand more......
Thanks to both of you for the input. If anyone else has anything to say on molds please add a comment.