Multi-stage casting

[Strawman]

Hey all, I have been looking for a way to use multiple molds for one piece. I’m not even sure what to search for, so I haven’t had any luck with google.
The idea is to cast a piece with one type of resin and then put the cured piece into a second mold that has a little more negative space than the first, and use a second kind of resin to finish it.
So, is this even a thing?

[pbell0000]

Oh yes, people definitely do that. I work in the medical device field and we do that occasionally, especially for injection molding. We call it overmolding, I think I've heard it called two stage molding as well. I'm more familiar with injection molding than casting, but it's a little trick because shutting off the part you are molding over can be tough. Little gaps, different sizes in the part can lead to flashing. Other problems I've seen is getting the parts to bond properly and not have one melt the other. I once worked on one overmold that took me and the injection molder 4 months to work properly.

It's definitely possible to do, think of it like a puzzle. Where do you want the parts to touch, how will you suspend the one part to be over molded in the correct location and not allow it to move. Do you want the parts to bond or not. Keep in mind the direction of shrinkage, that can impact you to. Shrinkage might make it easier, help the parts to bond. Good luck!

Paul

[mangozac]

Good description, Paul! Strawman, I don't really have much to add: it is pretty much just a matter of working out the procedure to use

[Strawman]

Overmolding! I’m finding information now. I figured it would be tough to get this working with resin casting, but now I can start learning about it.

Thanks guys, I’ve been looking for this one for a while.