I'm using Alumilite Clear Slow, mainly for the long work time.
I exclusively cast in extruded aluminum tubes and PVC pipes. I usually mix 2 colors, stirring them until they reach ~100-105*F, typically around the 10-12 minute mark. Then pour/mix/swirl them into the tubes and into the pressure pot (40-60 psi, depending on my mood).
I have no bubbles, but often see these strange deformations when demolding (see attached image). It's like the resin poured in, set a bit, then pulled away from the edge of the mold. Sometimes it's a large area, sometimes it's smaller.
I assume it's got something to do with air being trapped or voids being created by the pressure squashing the air bubbles...
Any advice as to what's happening here, and how to avoid it?
Last Edit: Jul 22, 2020 23:19:57 GMT -5 by elskeetro
I see a lot of issues with voids in the corners of my parts as well. The epoxy does naturally shrink as it cures. Not sure if trying to limit how hot the epoxy gets would help. This could be done by doing smaller pours and even looking at options of "heatsinking". I've looked into this a little but have not actually tried. I also agree with LawnBoy about potential bubbles or dissolved gases. I've seen that you can degas Part A and Part B separately to help remove dissolved gases. These dissolved gases can expand with the higher temperature during curing. Just some thoughts! No promises as I am still experimenting myself.