Magnet Posted March 18, 2017 Report Share Posted March 18, 2017 My subject says it all. I've done it with plastic and of course ceramic, but I'd like to make a one-part mold of a glass that I have. Simple cup, no undercut. If it were plastic I'm sure it would work perfectly. I've made many molds before, just never out of glass -- so I'm hoping that someone has experience with this so I won't waste time on an unfruitful endeavor. I'd appreciate any experienced advice. Thanks! Link to comment Share on other sites More sharing options...
oldlady Posted March 18, 2017 Report Share Posted March 18, 2017 my attempt was unsuccessful. mostly because i could not find a separating agent that worked. that attempt was to put the plaster inside the glass baking dish. i may have used a glass dish with a slight undercut as well. not a good experience. later, i used a handmade glass form for a slump mold. it worked well but the handmade nature of the glass form was uneven and i was not happy with the final plate. good luck. Link to comment Share on other sites More sharing options...
Infinite Posted March 18, 2017 Report Share Posted March 18, 2017 I've made serveral plaster molds of glass cups and they were fine. So I think you should definitely give it a try. Link to comment Share on other sites More sharing options...
Chilly Posted March 18, 2017 Report Share Posted March 18, 2017 Yes. Taken from Lark Ceramic's "The Essential Guide to Mold Making & Slip Casting". Link to comment Share on other sites More sharing options...
Sputty Posted March 18, 2017 Report Share Posted March 18, 2017 . Link to comment Share on other sites More sharing options...
Magnet Posted March 18, 2017 Author Report Share Posted March 18, 2017 Sweet! Thanks a heap for the considered answers and that excellent chart. Now, to the plaster! Link to comment Share on other sites More sharing options...
Marcia Selsor Posted March 18, 2017 Report Share Posted March 18, 2017 I have made molds of large glass convex light shades. I used vaseline and another time WD-40. Marcia Link to comment Share on other sites More sharing options...
High Bridge Pottery Posted March 18, 2017 Report Share Posted March 18, 2017 Ann - that is a very useful table! Thanks for reproducing it here. Have you ever seen a source for oil clay in the UK (or elsewhere in Europe)? (I admit to not looking very hard, and also to being lazy...) EDIT: ------------------------------------------------------- To answer my own question, pottery suppliers are not the place to look; art suppliers are. Found loads of sources, most of whom deal with sculpture rather than ceramics per se. See. Not so lazy after all. Isn't oil clay just called Plasticine? I have made one parts using a glass. Few mistakes I made, first time the glass was full of air and when I poured plaster it came unstuck from the base. Now I made that mistake the glass was full of plaster so no air pocket to lift up the glass any more so you win and lose. Make sure to add soap otherwise it is impossible to get the glass out. Link to comment Share on other sites More sharing options...
Sputty Posted March 18, 2017 Report Share Posted March 18, 2017 . Link to comment Share on other sites More sharing options...
Mark C. Posted March 18, 2017 Report Share Posted March 18, 2017 glass is easy to make a mold from-just get a good release. Link to comment Share on other sites More sharing options...
Stone Spiral Posted March 21, 2017 Report Share Posted March 21, 2017 What would you use as "soapy release"? I am going to try this this week - I have a large, gorgeous glazed porcelain bowl that I would like to make a mold of. I want to make sure I put the right release agent on it, so that I don't damage the beautiful bowl in the separation process. Link to comment Share on other sites More sharing options...
Chilly Posted March 21, 2017 Report Share Posted March 21, 2017 What would you use as "soapy release"? I am going to try this this week - I have a large, gorgeous glazed porcelain bowl that I would like to make a mold of. I want to make sure I put the right release agent on it, so that I don't damage the beautiful bowl in the separation process. I bought mine from a pottery supply place. It's like jelly, and needs mixing 50:50 with water. I've read that you can use Murphy's Oil Soap? but not found that in the UK. Also heard of people using dishwashing liquid, but you need it to be quite thick. Found this through good old google: https://books.google.co.uk/books?id=naUbS2Hng5EC&pg=PA78&lpg=PA78&dq=soapy+release&source=bl&ots=94ZhDgo3dO&sig=C9H5Mxd86EWaNMJjBTpjSpJnyG8&hl=en&sa=X&ved=0ahUKEwiRm8vLiOfSAhWnLcAKHQcNBTYQ6AEIODAI#v=onepage&q=soapy%20release&f=false Link to comment Share on other sites More sharing options...
Mark C. Posted March 21, 2017 Report Share Posted March 21, 2017 http://www.axner.com/pure-lube.aspx Link to comment Share on other sites More sharing options...
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