2 years ago#1
Guest
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Will Oogoo (silicone caulk mix) destroy a plaster mould?
I am experimenting with making silicone dolls using Oogoo - silicone caulk and cornflour (UK name). I want to use a jointed armature, so using press moulds, and a putty consistency silicone, is easier than pouring. I have some very nice, very expensive plaster doll moulds originally designed for using with poured porcelain, but I am rather wary of using the Oogoo in them in case the acetic acid degrades the moulds. Has anyone any experience of this? I suppose - given these are for my own experimental use only - I could take a cast, and remould from that in another material - any advice?

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2 years ago#2
mickpearson
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HI.i don't have any experience with making dolls. but this subject has come up a lot of times and there has been lots of answers.if you look at the pages concerning what you want to do. and look at some of the answers given. why don't you mix a little plaster and put a little of your silicon on it to see what if any effect it has on the plaster. there was a suggestion on some ones answer that they use a plaster and pour silicon in the mould but i dont know if it was the same type of silicon that you use.

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2 years ago#3
Frances
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Thanks Mick - I have searched, and there is lots of excellent advice on using silicone moulds to cast plaster, and a few on casting silicone in plaster, but all use pouring silicone, which I think is a different cure. You are probably right that I will need to experiment a bit more before risking my best moulds - perhaps the oxime cure caulk would be a better bet, even if it is more expensive. If it works, I may invest in proper medical grade putty, but I'm still at the kitchen alchemy stage at the moment.

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2 years ago#4
mickpearson
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YOUR WELCOME.
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2 years ago#5
Leslie
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Hi,
I'm trying to cast silicone(the kind you buy in a DIY store and smells of acetic acid) in a plaster mold. Sounds a bit like what you're trying to do. Did you have any luck in finding out if you need to use a release agent on the plaster and if so, what works best?

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2 years ago#6
mickpearson
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HELLO. to the both of you leslie and frances. please don't tell me you are both using d.i.y silicon to make moulds. i come from the uk. so sometimes you have different names for the same products that we might have in the uk. so i assumed leslie was talking about a mold or mould we say in the uk. why do we have to be different all the time. you cant use d.i.y silicon for making moulds. get in touch with smoothon.com. or buy mould making silicon or silicone. as we say in the uk.from ebay or anywhere on the web. only buy what you think you need you don't have to pore it on. you can paint it on with your paint brush. and you don't have to use a release agent. but it is better if you do. also some silicon rubbers come in a 100 to 10 base. witch would require weighing on scales. or you can buy a simple one to one silicon. witch would be much easier for the beginner

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2 years ago#7
mickpearson
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mould making silicone rubber that you buy from suppliers. you can ad an agent called dedner. witch makes silicon feel like real skin. and makes it much softer to touch. hope that helps but i don't know anything about dolls but i know about making moulds and about most of the rubbers used

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2 years ago#8
fjm
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Oogoo is a silicon paste/putty made with silicon caulk and cornflour - fascinating to play with, although I don't know how durable it is.

I am actually experimenting with using the silicon putty in plaster doll moulds - it needs to go over a jointed skeleton, so poured silicon becomes very difficult! The issue I was considering was whether the putty would damage the plaster moulds. It needs to be at the nearly but not quite cured stage to work the way I want it to, and then releases with just a dusting of cornflour. I think for pouring it would be necessary to seal the moulds first - there is good advice elsewhere on here of how to do it. One method is to use vaseline, and warm it to the runny stage with a hair dryer so that the excess runs off and only a very thin layer is left.

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2 years ago#9
mickpearson
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HI fjm. thanks i don't know i make moulds and castings if i can help out a little in something i say then good.there are a few topics on the subject so thanks for getting back to me. mould making silicon can be thickened into a butter and some people use it aswell for making life like babies. and sometimes people have got the type of silicons mixed up. as there has been people thinking you can use d.i.y silicon for making moulds and you cant.
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2 years ago#10
Leslie
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Hi again.
Thanks for the replies.
Sorry about any confusion. I'm not interested in making a mold (mould) from Silicone. This appears to be what most people want to do.

What I want to do instead, is make a plaster mold and then cast clear silicone in that mould so that I end up with a silicone product. The silicone cast will be thin, less than half an inch and about 6inches x 6 inches. Like I said, I do want to use DIY silicone - the kind you buy in any hardware or DIY Centre!

There's a link I've found that, if I understand it correctly, allows you to make a silicone that will pour, using readily available and inexpensive materials - DIY Silicone, liquid Glucose and Mineral Spirits (White Spirit in the UK):
http://www.instructables.com/id/Using-Silicone- Caulking-to-Make-Molds/step3/Mixing-and-Setting/

I plan to use a very slight variation on this!

What I'm concerned about is that the silicone may stick to the plaster mold. As a release agent, all I can think of is using vaseline or a bar of soap, moistened with water using a paintbrush and well worked into the mold.

It's not high end casting that I'm after, it needs to be cheap though.

Any ideas about whether the silicone will stick to the plaster mold and if so, which release agent would be best to try? Please let me know whether you are guessing or whether you are advising from experience, that may help too. By the way, I want the casting to have the texture and qualities of clear silicone, I don't want it to be a hard casting and I'd like it to be reasonably durable.

Thanks again for your replies to my earlier post.

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2 years ago#11
fjm
Guest

Having started experimenting myself, I'd recommend just that - experimenting. The caulk is cheap enough that it's not prohibitive to try how different cures work, and if you make a few simple plaster of paris moulds to play with it doesn't matter too much if they get spoiled during testing. One thing I have discovered, after mixing a lumpy, useless mess, is that the "safe" white spirit substitute doesn't work - not the one Wicke's sells anyway!

The combinations of different cure caulks, different thinners, and different moisturising agents (cornflour, chalk powder, etc) seem to mean that many of the variations are yet to be tested. But if you are aiming for a clear silicon model up to 10mm thick I think you may be facing a different set of problems - cornflour and similar agents are used to disperse moisture through the caulk so that it will cure at thicknesses greater than the 1 - 5mm it is designed for. Without such an agent - which will inevitably create an opaque mixture - the caulk won't cure in thick layers. Glycerine may do the trick, but I've read it can make for a fragile end result.

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2 years ago#12
mickpearson
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HI LESLIE. i understood what you where saying. that's why i made reference to the silicone.the silicone that i use fore making moulds dose not need a release agent as most silicones don't on plaster. but it is better to use them as sometimes rubbers stick a little as the rubbers draw moisture from plasters. you can buy spray wax release agents.for this purpose. i don't know about the type of silicon you are going to use. so iv'e gave you my honest answer to your question i never guess an answer as an answer is critical in my opinion. if i don't know i will research. if i still don't know ill tell you i don't have a scooby. if you get in touch with smoothon.com youl be glad you did. and you can speak to there tech dept.and still buy the products that you are going to use. i once bought a substitute for white spirit from wickes it was rubbish. you are better with the real white spirit.but i don't see any harm using vaseline as a release. better safe than sorry.

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