Best casting material

[mindfad]

Hello All

I just order some of the instant mold to try my hand at some very minor sculpting and molding/casting.

What are the recommended cheap ways to go ahead and try this: and any cons associated with materials

I have seen reference to green stuff, miliputty, and hydrostone used.

Thanks for any help in the matter

[snitcythedog]

Milliput and green stuff are pretty good with the Instamold.  If you cast in hydrostone it will be brittle.  General rule plaster is stronger the thicker it gets.  It is good for larger structures.  Resin is another option.  Hope that helps.
Snitchy sends. 

[superflytnt]

If you have molds, such as Hirst, go with Smoothcast 300. So, so easy to work with, sets in 3-5 minutes or so, and is incredibly durable. 20$ at Misterart.com, at least it was when I last ordered.

I've also used 50/50 Lightweight hydrocal/hydraulic cement and it's hard as dental stone almost, but it takes a half hour to set up.

Go to Hirstarts.com and watch the plastic casting tutorial. Its magical.

[Dewbakuk]

Don't use resin! Smoothcast is a resin.

While they are great materials to cast in, they need a stable mold material. The issue here would be that as the resin cures it gives off quite a bit of heat from the chemical reaction as the two parts combine. Instant mold melts at a low temperature which makes it really easy to use but the last thing you want is to pour in a hot material that then melts your mold.

Best thing to use is green stuff/procreate/very fine milliput. Just push it in from one end to make sure the air is pushed out.

[superflytnt]

I've made hundreds and hundreds of casts with Smoothcast, and my molds are still as good as the day I bought them, many moons ago. If you've got decent molds, there is no reason not to use it.

One of the primary reasons I got away from plaster and dental stone is that they beat the shit out of the molds upon extraction.

I've even used that pour on latex crap for making molds, and while it's stinky and messy, it works fine, and the mold doesn't seem to degrade any. I don't have AS much experience with latex (natural) molds, but I can guarantee you that RTV molds (Dow Silastic...purchased Hirst Arts...) stand up to resin just fine. For YEARS.

[Dewbakuk]

I've made hundreds and hundreds of casts with Smoothcast, and my molds are still as good as the day I bought them, many moons ago. If you've got decent molds, there is no reason not to use it.
.....
I don't have AS much experience with latex (natural) molds, but I can guarantee you that RTV molds (Dow Silastic...purchased Hirst Arts...) stand up to resin just fine. For YEARS.

Which is all very nice for you. However it shows you didn't actually read the initial posters thread 

Mindfad was asking what is the best casting material to use with Instant Mold. This stuff:



It's a great material for making simple push molds to get detail bits from figures such as Space Marine icons and I've used it to make an arm for a figure when I got a mispacked unit box. However it is a very low melt material as it's designed to be used on the fly and melts by putting it in warm water and putting resin into that will probably destroy it when the chemical reaction kicks in.

[Grimmnar]

As well keep in mind there is a difference between InstantMold and Instamold. With that said, keep in mind that InstantMold is just a repackaged version of Oyumaru, the original product. Finding it on eBay or other sources will usually net you twice as much for at times half the price of InstantMold.
As for InstantMold though Green Stuff is the most popular way to go that i have seen. As mentioned about InstantMold is a low temp agent used for press molding. Take a Google SearchFu trip and see what shows up. You will find quite a lot of vid's to watch. :-)

Grimm

[FramFramson]

I had quite a bit of trouble with greenstuff myself. It was a bit too hard and wouldn't quite press into the crannies of the mold I made. Don't know if anyone else had that problem with Instant Mold or GS?

[Dewbakuk]

I used procreate rather than GS and had no problem but GS should be fine if you use it straight after mixing.

[Zaheer]

Milliput works very well for me. Best push the putty into the mould with a sculpting tool.

[Christian]

If you add more yellow when mixing GS, it becomes a lot softer.