Min Posted October 3, 2014 Report Share Posted October 3, 2014 I don't make many molds and have never tried using silicone caulk, anyone try this with success? I thought it had possibilities. http://www.vickilynnwilson.net/PSU_PDFS_WINTER_11/SILICONE_MOLD_TUTORIAL_PP_PSU_3D.pdf Link to comment Share on other sites More sharing options...
Colby Charpentier Posted October 3, 2014 Report Share Posted October 3, 2014 If you're on a budget and don't need great surface information, this works. A sheath mold is necessary to hold the form, though. Plaster gauze works fine for this. Link to comment Share on other sites More sharing options...
Mark C. Posted October 3, 2014 Report Share Posted October 3, 2014 It will cast undercuts which can be an issue later in clay. Plaster works so well Even plaster gauze Since the silicone has no mo sistrum sucking I cannot see the needs? Small press molds for epoxy work? Or are you thinking clay? Mark Link to comment Share on other sites More sharing options...
Min Posted October 4, 2014 Author Report Share Posted October 4, 2014 My thought was that since the mold would be somewhat flexible then slight undercuts would be okay. I was thinking of using it for shallow sprig molds so the non absorbent properties wouldn't really be an issue on thin pieces. I usually use bisque or plaster but the idea of having undercuts appealed to me. Link to comment Share on other sites More sharing options...
neilestrick Posted October 4, 2014 Report Share Posted October 4, 2014 Even though it's flexible, it's not that flexible. I doubt you could get undercuts out without bending or breaking the clay. Link to comment Share on other sites More sharing options...
Colby Charpentier Posted October 4, 2014 Report Share Posted October 4, 2014 Generally this would be used to pour waxes for investment molds. As mentioned, use with clay would be questionable. Link to comment Share on other sites More sharing options...
Chris Campbell Posted October 4, 2014 Report Share Posted October 4, 2014 I am fairly lazy so that method is so work intensive it makes me tired just to read it! There are so many other choices from plaster to latex ... Latex makes a super flexible mold that stays that way for years. Step one ... Get object Step two ... Brush on latex Step three ... Let it dry. Repeat with thin layers until the mold is as thick as you want. Bonus with latex is you can take it to the object, such as tree bark or stone patterns. Potters are also trying mold products that dentists use for impressions. Quick and they don't shrink. Link to comment Share on other sites More sharing options...
Colby Charpentier Posted October 4, 2014 Report Share Posted October 4, 2014 Potters are also trying mold products that dentists use for impressions. Quick and they don't shrink. Alginate is an option for casting body parts or similar high detail objects. It's more rigid and much less durable than silicon rubber, but much cheaper, and has better release. Link to comment Share on other sites More sharing options...
Min Posted October 4, 2014 Author Report Share Posted October 4, 2014 Potters are also trying mold products that dentists use for impressions. Quick and they don't shrink. Alginate is an option for casting body parts or similar high detail objects. It's more rigid and much less durable than silicon rubber, but much cheaper, and has better release. What is the difference between the silicone rubber sold for mold making and the 100% silicone sold for caulking? (apart from cost) Link to comment Share on other sites More sharing options...
Colby Charpentier Posted October 4, 2014 Report Share Posted October 4, 2014 What is the difference between the silicone rubber sold for mold making and the 100% silicone sold for caulking? (apart from cost) I don't know what's going on chemically between the two products, aside from the curing system. The silicone rubber sold for mold making tends to be a two part system, whereas silicone caulking is a one part system. The mold rubber tends to be more rigid, but additives are available to make it more flexible. In terms of cost, the price per gallon is marked up ~$10-15 for smooth-on rubber products vs. generic silicone caulking. Not as bad as I thought it was. Link to comment Share on other sites More sharing options...
Chris Campbell Posted October 4, 2014 Report Share Posted October 4, 2014 Silicone used for caulking is very thick ... I just cannot see it being able to pick up fine detail. It smells awful, takes a long time to dry and can irritate skin. The smell lasts even when it is dry. Latex smells at first but not when it is dry. You can even use slip for molds ... let it dry and don't fire it ... Surprising how long it will last. Link to comment Share on other sites More sharing options...
Min Posted October 4, 2014 Author Report Share Posted October 4, 2014 Thanks for the replies and suggestions. Doesn't sound like anyone is pro this idea, I'll cast it aside for now (bad pun intended). Link to comment Share on other sites More sharing options...
Mark C. Posted October 5, 2014 Report Share Posted October 5, 2014 Potters are also trying mold products that dentists use for impressions. Quick and they don't shrink. Alginate is an option for casting body parts or similar high detail objects. It's more rigid and much less durable than silicon rubber, but much cheaper, and has better release. What is the difference between the silicone rubber sold for mold making and the 100% silicone sold for caulking? (apart from cost)mold rubber is two parts and they set very firmThe walls are hard and can take the thick plaster molds from treating them roughly, silicone is way softer My master molds last forever and you can make working molds from them Mark Link to comment Share on other sites More sharing options...
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