I am trying to cast small parts - gaming dice - by rotocasting polyurethane (EasyFlo). At the moment I'm just doing 18mm cubes to get the hang of it. And I don't have a rotocasting machine so I am doing manually.
What I find is that the material seems to accumulate in the corners of the dice, and the faces are thin, and tend to bulge. I'm not sure if this is two separate issues - the unevennness and the bulging - or whether they reflect the same problem. It's fairly consistent - ALL the faces are thin and bulging.
As I say, I'm just doing it by hand and want to build a rotocasting machine and hope that this will help. Because the parts I'm casting are small I don't need powerful motors so I think I can have two separate battery-powered motors rather than trying to gear one motor. But before buying the motors I need to have an idea of the right revolution speed for what I'm doing. I'm assuming that slower is better, so that the material has time to settle on the faces rather being constantly sloshed into the corners, but am I right, and if so how slow is slow enough? And is there anything else I should be aware of, given the difficulties I've experienced with my initial experiments?