I'll be milling some moulds out of epoxy. I would love to try the s120 sealer but it's just too expensive to ship to the states. Does anyone know of something similar I can get here? Also I'm curious what type of epoxy/filler will work nicely for this? I will probably be building up a layer of epoxy over pre milled mdf leaving a few mm thickness for epoxy and milling final shape into that. Already tried bondo and that works, but I think epoxy/filler will work nicer and be tougher, just not sure what to use. Another guy mentioned coating the mould in Teflon tape which i might consider, but I want to see what is available to use that is similar to s120. 

I guess I need to find a better way of searching. Here's the problem, when I search for mold release agent, it's just the non stick compound that's gets applied after the mold is done. If I search mold primer, paint, or sealer all I get is mold killing/blocking stuff. Over here we call it a mold, over there it's a mould, same issue both places. Composite mold/ moldy bread, or mouldy bread. Paint/primer/sealer for mold is a lot more common than paint/primer/sealer for "a" mold, so that's all Google shows me. I'll send some emails to composite companies around here asking about specifically what I'm looking for. I tried to join the forum composites central, thinking they might be able to direct me to some products in the US, but their spam blocker is broken and they aren't answering email. 

On another note, yesterday I poured a block of epoxy with some cell-o-fill filler in it and it machined beautifully. Pretty much just like delrin would mill. So that part of it I think I have figured out, just need to do some more searching to figure out what to coat it with to get the nice gloss before applying release agent.