Mold Question for 3D model

darthviper107 · Post by **darthviper107** » Thu May 26, 2011 3:16 pm

I've got a 3D model of a pistol that I'm looking to get printed and made into a 1/6th scale object for a custom figure (Malcolm Reynolds from Firefly).

Most of it is straightforward, and a 3D printer can print any shape, but I'm looking to be able to make casts of it.

So what I'm wondering, if any casters can take a look, would there be any issues with casting this? It's going to end up being 57mm long. I think the only issue I can see is the pins on either side. I can have the gun barrel as a separate piece if needed (as shown in the picture) if that will help. I'm just concerned that in a typical mold those pins would snap off if you try to remove it. So I'm wondering if I might have to modify that design a bit so it can be molded.

http://img708.imageshack.us/img708/7015 ... limage.jpg

Umi_Ryuzuki · Post by **Umi_Ryuzuki** » Thu May 26, 2011 5:40 pm

The pins would mold fine, however, the nubs on the end would be
excellent air bubble traps. If you are vacuum, or pressure casting, it
shouldn't be a difficult piece to cast and fill the voids...
Just don't make the barrel, or any recesses too deep.

How big is this at 1/6th scale?

darthviper107 · Post by **darthviper107** » Thu May 26, 2011 5:52 pm

57mm long at 1/6th scale, so pretty small.

My main concern is the nubs (bolts) on the pins, is that a detail that wouldn't get stuck in the mold do you think?

Does it make it better for the gun barrel to be a separate piece as shown there or would it be just fine to be attached?

Umi_Ryuzuki · Post by **Umi_Ryuzuki** » Thu May 26, 2011 6:24 pm

With the barrel detached, I would be concerned with how thin the top of
the gun body is, at the overhang where the gun barrel attaches.
Thin is acutally more difficult to cast properly, than the bolt nubs.
How thin is that shelf at 1/6th scale?

With a Silicone RTV, the mold should be flexable enough to allow the
extraction of the "nub". As long as the material is fully cured, the "nubs"
should release with out being deformed, or pulled off.
Then again, how thin is the connecting piece for the nubs at 1/6th scale.

Might be something to consider... maybe the nubs can be cast separtely with a small socket, so that they just glue on.

I cast these inverted in a mold, the trick is not getting them out, it's getting the resin into the mold.

http://www.rcgroups.com/forums/attachme ... id=3976459

darthviper107 · Post by **darthviper107** » Fri May 27, 2011 11:13 am

Where it connects is about 0.655mm thick, so I'm thinking that may be too thin and I should extend it to attach to the body of the pistol.