• Will this allow to mix a few batches of resin and pour this in to the mould before the whole thing sets? With anything, test first but you are more likely to have colour differences and casting errors/fractures
• What's the maximum safe amount of resin/ATH amount to mix in one container? Any idea on pot life? - Resin dependent, but the manufacturer should be able to give you an idea. I've seen less than 1" in the bottom catch fire with a quick curing PE, I mix a maximum of 1.0kg in one hit typically with a long pot life epoxy, and 0.75kg of PE
• What's the best choice of resin? EC sell xencast P6 which I plan if suitable.
• Can I do an in-mould coating of pattern coat primer to provide a surface that will accept paint straight out of the mould?

why are you casting such a large part? Surely wet lay would be a better option, you're talking boat quantities of resin there. You'll use less expensive resin with a CSM or woven roving and you'll reduce the exotherm. Layup both sides then mould the two together in the last pass off a resin rich layer?

I would be extremely amazed if there is any thermoset resin system out there that can do a 40kg pour in one shot, even with filler... That is some mass. I'd wager you will need to do it in multiple pours. 

For me any resin with more than 1kg is large as you likely have to consider resin exotherm due to the volume and heat.

I did a few large castings a while ago that was about 8kg resin.

Hi everyone.