RTV silicone

japgoth

New Member
Hi guys since i'm off work for a while, ive been busy trying to finish this bio helm out.
Now I'm hitting a brick wall. How much silicone is normaly needed? As I don't want to find out that I haven't got the right amount with a half done cast.
 

smasher

New Member
rtv silicone is cool stuff i gett all myn from tomps mold makeing surrplys you are going to need to get thickotropic thickener as well i does not maker if you run out and have to wait for more is silicone only sticks to silicone and it dose not matter if are have to add more a 1inch thickness is the best for a bio
 

smasher

New Member
rtv silicone is cool stuff i gett all myn from tomps mold makeing surrplys you are going to need to get thickotropic thickener as well i does not maker if you run out and have to wait for more is silicone only sticks to silicone and it dose not matter if are have to add more a 1inch thickness is the best for a bio
http://www.tomps.com/
 

Usurper

Well-Known Member
Id personally phone MOULDLFE and ask them, TOMPS stuff is good but i personally prefer MOULDLIFES as it give more pulls before giving out.
 

hez1

New Member
As far as amount, I've yet to meet the bio that couldn't be molded with 3 of smooth-ons trial size kits. If you don't want to go with smooth-on, their trial size kits amount to around 2 pints of silicone each, just for reference when looking elsewhere.
 

frosty

Sr Member
I've used this stuff before with good results ebay item number
320390384572
They also sell thixotropic
This one is one of the easiest to use i've tried a few and this is one of the better ones, mouldlife is good as well
A 2 kilo kit with thixo will be more than enough, an unthickened detail layer first,once that dries then add another layer with thixo added
So theres a few options from different members, hope you get sorted out
 

japgoth

New Member
hmmm very intresting regarding the silicone's so i gathered that i'm looking for something that has High tear resistance - also heat resistance?
Also ive been looking on how to cast it off. I'm trying to move away from resin as due to a small work space. And the last time i used fiberglass and resin it stank the whole house out (even when I was working outside)

anything eles that i can used that is less harmful?
 

hez1

New Member
Heat resistance is only particularly important if you think you might want to experiment with casting metals. I believe pewter is one of the metals that can be cast into certain silicones. Tear strength is important. Rebound 25 has a tear strength of over 100, which I've found to be perfect. Lower tear strengths will work if your bio has few undercuts and is quite uniform (P1, for instance). Something like a celtic will shred molds to pieces if you don't have high tear strength AND stretchiness.

Certain smooth-on resins work well for slush casting, and are almost odorless. At least, compared to f/g resin...

Looking at the mouldlife page, I'd say this resin http://www.mouldlife.co.uk/?pageid=prodshow&prodid=199 sounds like it would be worth a try as well, and pretty comparable to the smooth-on stuff.
 

crawjaw

Active Member
You could try Jesmonite as a safe alternative to fibreglass and nasty smelling resins. I've been using it on my P1 build (see Resin cast Predator) and it is easy to use, doesn't stink to high heaven and the product is water soluble. I got all my supplies from Propbuilder Website. I thoroughly recommend the product, and the seller is reliable and his costs are competitive .
 

japgoth

New Member
You could try Jesmonite as a safe alternative to fibreglass and nasty smelling resins. I've been using it on my P1 build (see Resin cast Predator) and it is easy to use, doesn't stink to high heaven and the product is water soluble. I got all my supplies from Propbuilder Website. I thoroughly recommend the product, and the seller is reliable and his costs are competitive .
oh yes i was looking at jesmonite, quick question regarding this as from most pictures i have see, it does look like plaster or stone. but how does it feel? like resin or plaster? also painting on top of it does it soak the paint up.
 

crawjaw

Active Member
It sets hard like Stonecast plaster so its harder than normal plaster but obviously less dense than stone. Surface feel is similar to Stonecast so is more like plaster than resin. It can be drilled, sanded and isn't that hard that you can't scrape the surface using a sharp knife. You need to exert a fair bit of pressure to manually scrape it, so it is a very durable product. I laminate the Jesmonite with 1 layer of thin fibreglass, then two layers of quadaxial glass and a fianl thin fibreglass layer. End up with a cast around 4-5mm thick. It probably can be cast thinner for small pieces but as my build was over 6ft I wanted it fairly rigid. Manufacturer mentions 6mm thick and sandwiching chopped strand mat between the quadaxial but this is probably for industrial applications.
I haven't painted any yet but the product is deemed water resistant when cured and can be used outside provided it's sealed first. I don't forsee any problems with the material soaking up acrylic paint and I think there is a section on painting it on the manufacturers website.

Have a bash with Jame's starter kit Jesmonite Source and for more information give him a call. He's a top guy and he's also a modelmaker amongst other things. Check out his Iron Man build on the FXLab IronMan Build, as it is painted and quite an awesome piece of work. Note how he primed the suit before painting.

Good luck.
 
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