Easiest mold material/casting resins?

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davehal9000
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Easiest mold material/casting resins?

Post by davehal9000 »

What's the easiest molding material/casting resin out there? I'd like something that's forgiving if I don't get the ratios exactly right.
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Schadenfreudian
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Post by Schadenfreudian »

I've tried moulding rubber with a 1:1 mix ratio of parts, and it was awful, so I'd stick with a decent silicone rubber, which will require measuring pots for the components.

However, polyurethane resins tend to be mixed in 1:1 ratios, so they're more straightforward to use. Never ever try polyester resin - awful stuff.
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Post by vaderman »

I get my resin casting products from:

www.smoothon.com

The gallon polyurethan is about $68.

For the mold making RTV, you need to decide if you want a 10:1 ratio or a 1:1 ratio.

10:1 is cheaper (but it is still expensive) than 1:1. The last batch of RTV I got was 1 Gallon supply 10:1 ratio. This requires a digital scale for accurate measurement. The next time I get RTV I am going to get Smoothon's Oomoo 25. It is 1:1 and is only $32 more than the 10:1 I got, but there will be les error in ratio calculation.

For the resin, I use Smooth Cast 310. Drys white, hard resin. If mixed right, usually no bubbles. I really like this stuff.

Hope that helps.

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Post by Blappy »

The Smooth-On stuff is what is used here at BLAP! Models. The 10:1 ratio rubbers are far more durable so will last for far more castings the then the 1:1 ratio stuff.

The 10:1 ratio rubber is pretty forgiving too. I measure by volume (I add about 10% extra catalyst) and get great molds.
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Post by chasd25 »

Blappy wrote:
The 10:1 ratio rubber is pretty forgiving too. I measure by volume (I add about 10% extra catalyst) and get great molds.
Yeah, I always add a bit extra catalyst. The only time I ran into trouble is when I didn't add enough!!!!

I use a postal scale (cost me about $25) for measuring out the silicon.

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Post by TER-OR »

For home use, without pressure pots etc, I prefer the 1:1.
Yeah, they're not quite as strong but they're much more forgiving.

I like the SC321 from Smooth-on. You get decent setup time. With the very slow setup resins I found they're VERY finicky and vunerable to local concentration of the two parts.
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