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. 

Look for mould primers made by whatever company you can get chemical release agents from locally. Not your conventional primers, raher they are commonly a part of a semi-permanent release system so the idea is first you apply the primer, then the sealer, then the release agent. 

Marbocote, Zyvax, Necumer etc. Not sure what you can get in the states but I'm sure someone will have something similar. 

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. 

Ok, I think I found something. Chemlease Sealer 15 EZ. Seems to be a very similar product to s120. Can be applied by spraying or wiping, designed to give a mold a nice smooth base surface, fills microscopic porosity, etc. 

Nah the Sealer 15 EZ is the second stage product that I mentioned. I know the datasheet makes it sound similar but it isn't. It is the same base family, but it is made for sealing microporosity so will only have 0.5 - 1% solids, which means you would use a gallon of the stuff before you got any sort of seal let alone gloss. They are really only used to enhance the performance and durability of the release agent that goes on top of them. The primers are called primers because they are heavy duty, 10-15% solids. So they have a much much higher build, making it possible to seal heavy porosity and restore gloss. 

If you have local access to Chemlease though, have a look for MPP 713, MPP 2684W or MPP 2180. These are the Chemlease primers. The mother company Chemtrend also owns Zyvax, so Zyvax will have a similar product but I forget what it's called. 

Also have a look for Marbocote HP2002 or Necumer Necuron V7. These are excellent products, but they are European so I'm not sure you will find them locally. Be aware though that you likely aren't going to find these products in small quantities like Easy Composites supply. They have an extremely short shelf life, and the minimum quantity is very likely to be 1 gallon.

Essentially yes. Not every company classifies their products like that which does make it a little tricky to find. The S120 is a new addition to Easy Composites lineup, but these types of products have actually been around for many years - Chemtrend have already phased out some of their older versions.

I did a hell of a lot of research to find an equivalent product that I could get locally, and in the end I found it by looking at the safety datasheets and comparing the substance concentrations.