Im making a very easy and simple mold from fix-it-all plaster.The molds came out great.But,i cant get foam to release and i use a 2 part foam.I brush on Vaseline but if i dont brush on enough, the foam will not release and if i use too much Vaseline,the foam will fail to expand all the way.What the heck?What else can i use?AND YES,i did use the orange button but it was all on fiberglass,latex and resin.None on plaster molds that i seen.Any help is greatly appreciated.
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Go over to Smooth-On [dot com] and get some of their "universal mold release". aka PVA (polyvinyl alcohol).
Try Johnson & Johnson paste floor wax. you can buy this at Lowe's
Always let the mold completely dry.This takes 4-7 days.Then seal it with several coats of shellac.Keep adding coats till it stops drinking it up and starts to develop a sheen.After that has dried,use the Johnson and Jonson or Simonize.Apply at least 3 coats,let each one dry before applying the next.Don't buff between coats,just let it dry.Now do your foam.The first pour is always the worst for sticking.After that,each pour will get better.
PVA is not for plaster molds . It will just absorb into the plaster and be useless . Its bascially for fiberglass . Now do as Jim just said , either use shellac or paint and then your mold release . Van Dykes sells a release for this . Also , are you leaving your foam in the mold too long ? usually 10 minutes is enough . You want the foam to be a little flexible when you remove it , not rock hard .Rick
Follow Jim Bs instructions.
If you want to get a proper Urethane 2 part Foam release, use Smooth-On's Ease Release 1700. It is specially formulated for Foam specificly.
Vasaline and even Smooth On's Universal Mold Release (with is Silicone based, not a PVA) will not work and cause the foam to collapse. Plaster is also tricky to work with if the foam is rigid itself, unless it is a multi-piece mold that can be removed in sections if nessasary due to undercuts.
Hope this info helped steer you in the right direction.
Thanks every one.You helped allot.Greatly appreciated.