I use platinum based siliconeRTV for most all the mold and cast work I do... a little latex here and there.

My nornal distributor (PolyTek) also shows a variety of URETHANE based 2-part rubber RTV... has anyone ever used this? It is about half the price of silicone in 16 lb shipments.

Do you need to use a release agent for plaster and resin pours with Poly U RTV?

How good is the detail (should be good with a Shore Hardness of 25-30)

How long did they last before you niotiiced deterioration of the mold?

Awe c'mon... I know there are a ton of RTV junkies out there... surely SOMEBODY has tried the poly version instead of silicon, right?

Guys?
Hello?
Bueller?

I'm just getting started ...... and using whatever came in the Alumilite Kit.

Sorry

Matt

I'm a PU and silicone addict, all right. But I only used silicone rubbers, never heard of PU rubber. Sorry for that.
I'm wondering here : could you cast PU resin in flexible PU molds without the whole thing getting stuck together BIG way ?
I do know there are about 1000 different brands and types of mold material for sale out there. I tried about a dozen, and half of those really sucked. Now I'm happy with what I got, so I stick to that for the time being.

Jan

About deterioration : molds withstand the casting of plaster about forever. On the contrary, resin damages the mold. There must be some chemical reaction from the resin curing process that sucks the life out of molds !
With PU resin, they start breaking after 12 to 20 casts. This is not the case with plaster.

General - thanks for the update on PU and resin casting... I have about 100 molds done in various brands of Platinum-based Silicon Rubber, and intermix plaster and resin castings in many of them, and after years of use, have seen no real deterioration.... but I'm also maticulous about cleaning my molds after use. Thanks for the heads up on resin in a P/U mold.... that is NOT the way to go it seems. I'll just stick with my PolyTek 70-25 Silicon RTV from Bare Metal Foils... costs about $98 per 16lbs, but the durability and quality of the casting is probably worth it... unless anyone else has a better deal on a similar quality...