[Baal]

Hi, Im trying to do big castings basically encapsulating big marble pieces, so I’m using 40 liters of resin, I’ve used 85/15 resin monomer ratio with 0.5% promoter and 0.5% starter (catalyst).

I’ve gone down to even 0.2% catalyst and the resign took hours to form a gel and after 24h it was broken, then somebody suggested to do it in steps, catalyze 1/8th of the volume and pour, wait for it to gel (around 20min) and pour the next part and so on, but after the 3rd part the exothermic reaction was so violent it cracked and the wood mold was so hot you couldnt even touch it.

Has anyone made castings of these big volumes? im starting to think they cant be done in polyester resin

[Katherine Swift]

Polyester resin can be a fussy beast! Generally, the amount of catalyst you add is dependent on the depth of the casting, not the total volume of resin to be mixed. Your resin is getting very hot (which is what is causing the cracking), so I would suggest cutting the amount of catalyst you are using by half as a starting point.

Have you spoken with the manufacturer about your dilemma? Have they offered any advice?

[Katherine Swift]

While this article applies to epoxy resin, it might be helpful to you here: https://www.resinobsession.com/resin-resin-resin/deep-pour-resin-casting-tips/

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