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Polytek materials
Discussion started by Duane , on 09 November 12:42 AM
Hey guys,
First off, I love the idea of this group! I would've loved to have a centralized databank of stop motion oriented silicone information when I first started researching all this stuff... This will make silicone R&D a heck of a lot easier in the future, not to mention how much nicer it will be for everyone just starting out with silicone. I hope it catches on.
So anyway, I finally found a local place around here that sells silicones and other mold-making materials. What a relief! The shipping costs have been killing me. The confusing part is that it's all "Polytek" materials, or at least that's who their distributor is. I'm used to using Dragon Skin, GI-1000, Smooth Cast 300 Resin, and Ultracal 30. These guys are selling Tinsil 70, Platsil 71 and 73, Platsil Gel-10, EasyFlo Liquid Plastic, and Hydrocal FGR-95. I've been doing some research, and I'm starting to think these different materials would be near-equivalents, just with different names. But one of them has me confused (and besides, this is a silicone-only thread right? I'll save the other questions for a different forum)
I asked the spokeswoman to look up GI-1000 to see what their "version" is. As I'm sure you guys already know, GI-1000 is a tin-catalyzed silicone that's great for resin casting (which is what I'm planning on using it for). She said their equivalent is TinSil 70-30 (tin-catalyzed), but she recommends going for the PlatSil 71 or 73 series instead (platinum-catalyzed). At the time, I didn't think to ask the difference between the 71 and 73 series, but the biggest thing that has me wondering is, do you guys ever use a platinum-catalyzed silicone to make your molds? I guess I don't see anything wrong with it... but I've never used it for making a mold (just casting). So, any thoughts? Has anyone used TinSil 70-30, or PlatSil 71 or 73, and can anyone compare their experiences to Dragon Skin and GI-1000? Thanks in advance for the help!
Duane
First off, I love the idea of this group! I would've loved to have a centralized databank of stop motion oriented silicone information when I first started researching all this stuff... This will make silicone R&D a heck of a lot easier in the future, not to mention how much nicer it will be for everyone just starting out with silicone. I hope it catches on.
So anyway, I finally found a local place around here that sells silicones and other mold-making materials. What a relief! The shipping costs have been killing me. The confusing part is that it's all "Polytek" materials, or at least that's who their distributor is. I'm used to using Dragon Skin, GI-1000, Smooth Cast 300 Resin, and Ultracal 30. These guys are selling Tinsil 70, Platsil 71 and 73, Platsil Gel-10, EasyFlo Liquid Plastic, and Hydrocal FGR-95. I've been doing some research, and I'm starting to think these different materials would be near-equivalents, just with different names. But one of them has me confused (and besides, this is a silicone-only thread right? I'll save the other questions for a different forum)
I asked the spokeswoman to look up GI-1000 to see what their "version" is. As I'm sure you guys already know, GI-1000 is a tin-catalyzed silicone that's great for resin casting (which is what I'm planning on using it for). She said their equivalent is TinSil 70-30 (tin-catalyzed), but she recommends going for the PlatSil 71 or 73 series instead (platinum-catalyzed). At the time, I didn't think to ask the difference between the 71 and 73 series, but the biggest thing that has me wondering is, do you guys ever use a platinum-catalyzed silicone to make your molds? I guess I don't see anything wrong with it... but I've never used it for making a mold (just casting). So, any thoughts? Has anyone used TinSil 70-30, or PlatSil 71 or 73, and can anyone compare their experiences to Dragon Skin and GI-1000? Thanks in advance for the help!
Duane
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Just wanted to give everyone here an update on my mold experience.
After listening to your advice, I went down to the store the next day to pick up some Platsil 73-29, but they were all out!
I figured I would come back later when they had some, but the lady at the store suggested I go with some of their 71-20, which apparently is the most popular blend they sell to sculptors. She said all the undercuts on my sculpt would benefit from the 20-shore hardness over the 29 as well. I decided to pick up a pack, partially to test out the material and partially to check out whether or not she would be a good reference on these things in the future, know what I mean?
Well, it was a success! There are a lot of undercuts on my piece simply due to the hair on the character... there really wasn't any way around it. But the mold is nice and flexible and I can sort-of muscle the piece out of there by bending the silicone, and it comes out beautifully. So far I have had 3 or 4 good pulls from the mold and haven't experienced any problems, and I really don't need very many more casts. The lower viscosity on this stuff, compared to the GI-1000 of which I am accustomed, was fantastic. I think there was only one or two small bubbles on the whole thing. And the silicone was SO effective that it even slid between the lumps of clay hair and his scalp! I had no idea it would be thin enough to fit in those tiny areas. What a great problem to have! haha
I am new to this forum, so I will try to post a picture I took as soon as I find out how.
Also, as an aside, one small pack of this stuff was not enough for both halves of the mold, so I had to wait (and wait) until their next shipment arrived, hence the delay in me posting an update. The stuff really didn't give me any problems and I could've finished it a day or so after posting my original message if I had bought enough the first time.
Thanks for the advice, my friends.
Duane
After listening to your advice, I went down to the store the next day to pick up some Platsil 73-29, but they were all out!
I figured I would come back later when they had some, but the lady at the store suggested I go with some of their 71-20, which apparently is the most popular blend they sell to sculptors. She said all the undercuts on my sculpt would benefit from the 20-shore hardness over the 29 as well. I decided to pick up a pack, partially to test out the material and partially to check out whether or not she would be a good reference on these things in the future, know what I mean?
Well, it was a success! There are a lot of undercuts on my piece simply due to the hair on the character... there really wasn't any way around it. But the mold is nice and flexible and I can sort-of muscle the piece out of there by bending the silicone, and it comes out beautifully. So far I have had 3 or 4 good pulls from the mold and haven't experienced any problems, and I really don't need very many more casts. The lower viscosity on this stuff, compared to the GI-1000 of which I am accustomed, was fantastic. I think there was only one or two small bubbles on the whole thing. And the silicone was SO effective that it even slid between the lumps of clay hair and his scalp! I had no idea it would be thin enough to fit in those tiny areas. What a great problem to have! haha
I am new to this forum, so I will try to post a picture I took as soon as I find out how.
Also, as an aside, one small pack of this stuff was not enough for both halves of the mold, so I had to wait (and wait) until their next shipment arrived, hence the delay in me posting an update. The stuff really didn't give me any problems and I could've finished it a day or so after posting my original message if I had bought enough the first time.
Thanks for the advice, my friends.
Duane
Sunday, 09 January 2011 00:19
i may be mistaken but the 71 and 73 #'s refer to the shore hardness . platinum catalyzed silicone is stronger [more casts] and has less adverse reactions to other materials , but it cost more . i have only used the smooth on stuff so iam sorry i can't give you a comparison .the best thing to do is vist the many different distributors sites [ like smooth on ect...] there is a ton of info out there.
Tuesday, 09 November 2010 22:50
I agree about this group - piggybacking of Ron's experience has helped me make the transition to silicone puppet skins with fewer stuff-ups!
I used Polytek Platsil Gel-10 for casting puppet heads, and I think it is virtually identical to Dragon Skin. I haven't used the shore 10 Dragonskin, but I did cast a head in the slightly softer Ecoflex 00-30 from Smooth-On. Except for the slight difference in hardness they were exactly the same to use. Both work with Psycho Paint and the Sil-Pig pigments.
I have used several mouldmaking silicones in the past, and they were all pretty similar, so the main thing is to get the hardness that suits your mould. The only drawback with tin cat is it's sensitivity to so many materials - but if you sculpted from a non-sulphur clay, it should be great for making a mould.
I would not fill a silicone skin with foam latex - it would not stick very well. Same with a soft 2-part urethane foam, it would not bond onto the silicone skin. I go the other way, and stick some urethane sheet foam on the armature, before pouring the silicone in to fill the mould - the liquid silicone bonds nicely onto the porous surface of the cushion foam. I haven't tried filling with Soma-Foama yet, I think Ron's the only one with experience of that, but it should bond to the skin which is what you want.
I don't know if Hydrocal is an equivalent to Ultracal or not - I mostly use Hydrostone, which works perfectly well for casting silicone or foam latex. For that matter I've cast foam latex in plain old casting plaster - it doesn't last through as many bakes but is ok for 2 or 3 casts. Not ideal but you can get away with it, so I figure Hydrocal would be much better than that.
I have a figure sculpt in Chavant NSP that is nearly ready for mouldmaking, which I will be casting in Ecoflex 00-30. I'm considering making the mould from epoxy resin instead of Hydrostone or other plaster, since I won't ever be casting it in foam latex or baking it. It would be a lighter, more compact mould and there is no risk of fine details ever breaking off. I'll do a test with the Ecoflex silicone on the epoxy, just to be certain it doesn't inhibit the cure, but if that works I will probably go for it.
I used Polytek Platsil Gel-10 for casting puppet heads, and I think it is virtually identical to Dragon Skin. I haven't used the shore 10 Dragonskin, but I did cast a head in the slightly softer Ecoflex 00-30 from Smooth-On. Except for the slight difference in hardness they were exactly the same to use. Both work with Psycho Paint and the Sil-Pig pigments.
I have used several mouldmaking silicones in the past, and they were all pretty similar, so the main thing is to get the hardness that suits your mould. The only drawback with tin cat is it's sensitivity to so many materials - but if you sculpted from a non-sulphur clay, it should be great for making a mould.
I would not fill a silicone skin with foam latex - it would not stick very well. Same with a soft 2-part urethane foam, it would not bond onto the silicone skin. I go the other way, and stick some urethane sheet foam on the armature, before pouring the silicone in to fill the mould - the liquid silicone bonds nicely onto the porous surface of the cushion foam. I haven't tried filling with Soma-Foama yet, I think Ron's the only one with experience of that, but it should bond to the skin which is what you want.
I don't know if Hydrocal is an equivalent to Ultracal or not - I mostly use Hydrostone, which works perfectly well for casting silicone or foam latex. For that matter I've cast foam latex in plain old casting plaster - it doesn't last through as many bakes but is ok for 2 or 3 casts. Not ideal but you can get away with it, so I figure Hydrocal would be much better than that.
I have a figure sculpt in Chavant NSP that is nearly ready for mouldmaking, which I will be casting in Ecoflex 00-30. I'm considering making the mould from epoxy resin instead of Hydrostone or other plaster, since I won't ever be casting it in foam latex or baking it. It would be a lighter, more compact mould and there is no risk of fine details ever breaking off. I'll do a test with the Ecoflex silicone on the epoxy, just to be certain it doesn't inhibit the cure, but if that works I will probably go for it.
Tuesday, 09 November 2010 17:48
Well, if it helps the issue with the Mrs any, a small kit of Soma Foama goes a long way and it won't come anywhere near your home oven! :)
Tuesday, 09 November 2010 15:13
Thanks for the insight! That confirms my suspicion I had after reading up on it. It seemed to me that the platinum-catalyzed silicones have less shrinkage (essentially none) and don't produce alcohol like tin-catalyzed silicones do. I thought, "Man, these sound even better than the tin-cat silicones to me but I never hear of anyone using them that way... Better ask the invisible online masters." I couldn't seem to shake the thought that plat-cat silicones are best as a skin, not a mold, despite the gazillion different hardnesses and viscosities available.
Alrighty then, I think I'll give Platsil 73-29 a shot and will let you guys know how it works. I'm really looking forward to it--especially because the 15,000cP viscosity is MUCH better than GI-1000's 50,000-70,000 for what I'm doing.
Just curious, it seems to me that with the proper release agent, I could probably cast Dragon Skin or PlatSil Gel-10 in a plat-cat mold with no issue, ya? Methinks I might be able to paint a plat-cat skin and fill it with foam latex. I know plat-cat silicone hates foam latex, but as far as I know foam latex is amicable with all silicones. That is, until I get up the courage to tackle this Soma Foama deal (of course I mean courage to face my wife after buying another new expensive chemical, not from trying something new; I actually like that part) ;)
Duane
Alrighty then, I think I'll give Platsil 73-29 a shot and will let you guys know how it works. I'm really looking forward to it--especially because the 15,000cP viscosity is MUCH better than GI-1000's 50,000-70,000 for what I'm doing.
Just curious, it seems to me that with the proper release agent, I could probably cast Dragon Skin or PlatSil Gel-10 in a plat-cat mold with no issue, ya? Methinks I might be able to paint a plat-cat skin and fill it with foam latex. I know plat-cat silicone hates foam latex, but as far as I know foam latex is amicable with all silicones. That is, until I get up the courage to tackle this Soma Foama deal (of course I mean courage to face my wife after buying another new expensive chemical, not from trying something new; I actually like that part) ;)
Duane
Tuesday, 09 November 2010 13:22
Platinum cure silicones are perfect for making molds, as a matter of fact - with some casting materials, it's mandatory. There are lots of casting materials that will not cure properly if cast in a Tin Cure mold. Some of the platinum cure silicones can be really tough rubbers and that's great for the life span and accuracy of mold keeping it's shape when casting out of it. So Yeah, platinum cure silicones are great for molds and you always need to check the compatibility factor when picking a new casting material. You can always find the material's data sheet online and there's always info in them about bad reactions with which cure type silicone so, do your homework whenever you try a new casting material.
I don't remember ever using the TinSil 70-30 or PlatSil 71 or 73 specifically (there are SO many!) but they are all good products in my opinion and the only real differences are hardness and cure times. So when you pick a silicone to use, go to the Polytek website and look up each product and compare the differences. There are so many versions because it's best to be able to tailor the material of choice to what's best for your specific needs. (fast cure for small simple molds, long cure for big complicated molds and/or de-airing in a vacuum chamber, etc...)
Lastly - If you're using your silicone for making molds, GI-1000 is probably a better choice but, that's only because I find it to be a stiffer rubber and will hold it's shape better without a 'mother mold' (or 'jacket mold' depending upon who you talk too) around it. But using Dragon Skin might be a better choice if what your casting has deep undercuts and you need something more flexible. They will both work fine, you just get 'a feel' for which is better for which project after you use all of them.
(Note- You can tell how hard a rubber will be by checking the 'Shore' letter, a rubber described as 'Shore A' will be super soft and stretchy and one referred to as 'Shore D' will be more like a rubber pencil eraser.)
I don't remember ever using the TinSil 70-30 or PlatSil 71 or 73 specifically (there are SO many!) but they are all good products in my opinion and the only real differences are hardness and cure times. So when you pick a silicone to use, go to the Polytek website and look up each product and compare the differences. There are so many versions because it's best to be able to tailor the material of choice to what's best for your specific needs. (fast cure for small simple molds, long cure for big complicated molds and/or de-airing in a vacuum chamber, etc...)
Lastly - If you're using your silicone for making molds, GI-1000 is probably a better choice but, that's only because I find it to be a stiffer rubber and will hold it's shape better without a 'mother mold' (or 'jacket mold' depending upon who you talk too) around it. But using Dragon Skin might be a better choice if what your casting has deep undercuts and you need something more flexible. They will both work fine, you just get 'a feel' for which is better for which project after you use all of them.
(Note- You can tell how hard a rubber will be by checking the 'Shore' letter, a rubber described as 'Shore A' will be super soft and stretchy and one referred to as 'Shore D' will be more like a rubber pencil eraser.)
Tuesday, 09 November 2010 09:16