Molds with Castaldo LiquaFast ICE RTV

Hi, I’m planning on using Castaldo LiquaFast ICE RTV for making molds of some fine-detailed parts that I’m printing in Grey V2 on my Form2. I see that this specific RTV (and only this one for that matter) is mentioned in the Introduction section of Formlabs’ whitepaper Vulcanized Rubber Molding with 3D Printed Masters (, however oddly it is not one of the two materials reviewed in whitepaper!

Is there a reason LiquaFast ICE was omitted from the reviews? It seems odd, as apparently it’s made specifically for casting resin 3D prints. For reference:

Can anyone confirm if Grey V2 will allow this RTV to cure?


Grey V3 inhibits the cure aggressively and is very hard to work with it without any coating, in some parts is possible to get acceptable results but it will always inhibit the cure at some level. The composition of V2 is a bit different from V3, maybe it will work but you won’t be able to buy it again.

If you have success please share :slight_smile:

I just tried making a mold of a part with a pretty complicated parting line (hand-cut the block mold), and had no problems. Grey V2 works great with LiquaFast ICE - the rubber cured perfectly and released the part, dowels (sprue), and toothpicks (air vents) easily and cleanly, without the use of any mold release, primer, or other coatings. Very impressed. I’ll be curious to see how Grey V3 stacks up once I’ve gone through my current supplies (have ~1.6L of V2 left).

It might be useful for others to know that this is a platinum cure RTV silicone.

Very good success also with Castable V2 resin and LiquaFast ICE. If you want to make multipart molds instead of trying to part with a scalpel you can make a very effective release barrier that will work on LiquaFast ICE from a bit of beeswax dissolved in lighter fluid (naphtha).

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