I have a project I am trying to rotocast. I was wondering if there is a magic number I should be shooting for, as far as wall thickness goes?
I want the total wall thickness to be between .100" and .125". I am using RC-3. I realize Slow Set 7 is advertised on the store's site as suitable for rotational casting, but I am making large scale model railroad kits, and I am concerned about the temperature resistance of Slow Set 7 for an application that could potentially be outside for several hours at a time.
I have tried casting in several layers, and tried thickening with micro balloons, but I am still getting some unevenness in my castings:
Ideally one pour ... correct? So like with any part, there is a learning curve. When rotational casting a hollow part you have even more variables. Amount of resin, shape of mold, thickness you desire, temperature of mold, rotation speed of inside vs outside frame, frame speed, surface area, and so much more.
If you pour too much resin all at one time in the mold, the resin can gel quickly in a big lump due to the heat it generates. A good starting point for inside to outside ratio for the frames is 3 inside rotations for every 1 rotation of the outside frame. Trying to keep the mold fairly centered is in the frame is recommended.
I would start with 2 coats and warming the mold. I'd also use approx. 50% microballoons to build some viscosity and allow it to flow and stick to the wall. As soon as the first coat gels, start mixing the second.