Casting

RIS_Mace · Post by **RIS_Mace** » Mon Apr 26, 2010 1:46 am

Hello,

I haven't done any work with miniatures, but I was recently messing around with casting and was wondering if anyone has tried casting their own minis. Looking at some metal melting point charts, it seems that zinc melts at a relatively low temperature, is safe, and is cheap (modern pennies are made from it). Any ideas on whether this would be feasible?

Thanks

wedge_hammersteel · Post by **wedge_hammersteel** » Mon Apr 26, 2010 2:06 am

The material for your mini's is not the biggest concern.

The main issue is what are you going to use to make the master that will hold up to the heat of the metal. Even for repeated castings.

Most of my research has found that resin is the way to go. But then again, the main issue is making an acceptable master in which to inject the resin.

Scoutdad · Post by **Scoutdad** » Mon Apr 26, 2010 2:54 am

The best process for our hobby is to use a RTV silicone mold and then cast the mini in either lead / pewter or resin.

The use of RTV silicone to create a master mold will allow you to create a master out of nearly anything, although sturdy materials such as brass and epoxy-putty are still the best. Styrene plastic can be used, but care must be taken to prevent deforming the mold.

Once you have a RTV silicone mold, you can then use it to make resin or white metal castings. From my experience, a mold made from a good, high-quality silicone base will make several dozen resin minis (unless there are lots of complex undercuts) and if care is taken, a few dozen white metal minis... although degradation of the mold will educe the overall quality of later castings.

This is where having a good, sturdy metal master becomes a big benefit. Once the mold degrades to the point of diminishing returns, you simply make another RTV mold from your original master.

I've made RTV molds of large, hex bases for Battletech minis and RTV molds of commonly used accessories for WH40K models and 1:35 scale armor models (i.e., packs, bedrolls, dunnage racks, storage boxes, crates, barrels, drums, etc.)

djdood · Post by **djdood** » Mon Apr 26, 2010 2:59 am

[Deleted by author]

RIS_Mace · Post by **RIS_Mace** » Mon Apr 26, 2010 3:41 am

Thanks for the replies all!

I looked up RTV silicone molding, and there were a few helpful Youtube videos that helped me visualize the process. The most simple process seemed to be making making a mold by pouring the silicone mix into a box holding the master, and then cutting the cured mold into two halves (though maybe taking a little more time and creating the two halves in the first place might be better?). In any case, this should be a fun summer project.

Scoutdad · Post by **Scoutdad** » Mon Apr 26, 2010 3:46 am

Taking the time to create the two halves from the start is well worth the additional time spent.

Having done it both ways myself, I'll never attempt it any other way again...

Scoutdad · Post by **Scoutdad** » Mon Apr 26, 2010 3:52 am

djdood wrote:[cross-posted with scoutdad]
The casting is typically done using a "roto-molding" machine ("spin-casting"), which forces the molten metal into the mold cavities and details using centrifugal force. Simple pour-casting with no pressure would have a hard time capturing small details like phasers, panel-lines, etc.

http://en.wikipedia.org/wiki/Spin_casting

Actually, I've used home-made spin casting before.

Once you create the mold...
drill a few small escape cavities in the bottom of the mold...
Fill the mold with resin / white metal...
Place the entire assembly into a "spin device" (I used a empty one gallon paint can)...
Then spin it by hand (you can go 'round and 'round - but you get dizzy)...
Over and around from the shoulder...
This forces the casting material into the finer details...

Hope this helps.

djdood · Post by **djdood** » Mon Apr 26, 2010 6:12 am

Just don't stop spinning, or you could get molten stuff falling on you...

Scoutdad · Post by **Scoutdad** » Mon Apr 26, 2010 1:24 pm

djdood wrote:Just don't stop spinning, or you could get molten stuff falling on you...

OK... I admit, that is a danger, but you can avoid such a catastrophic fate wiht just a modicum of care.

Post by **Steve Cole** » Mon Apr 26, 2010 2:43 pm

No, the master is NOT the original sculpture.

You make the original sculpture out of whatever (usually a combination of epoxy and brass).

You put several sculptures (originals) into a "master mold".

The master mold is then spun using production metal ( mostly tin, often some other metals as alloys, including a bit of lead to avoid brittleness, a little antimony for sharp details, etc.) producting "the masters".

The masters are then "cleaned up" by hand, including filling in any dents or divots.

The masters are then used to create a "production mold".

The production mold is then used to create a few hundred production copies. At this point, the production mold wears out and a new production mold is made.

Post by **Steve Cole** » Mon Apr 26, 2010 2:46 pm

Technically speaking, making your own copies of our miniatures (or any other company's miniatures) is and illegal copyright violation.

If you sell copies, you're doing to get found out and be in trouble. If you just use them yourself, you may not be found out but you are still breaking the law.

Making your own copies of your own sculpture is not illegal, but selling them may violate the copyrights of whoever did the original design (or the design you based it on). For example, doing your own sculpture of a D7 is using Paramount's design. Doing your own D23 design which is obviously "derived from" Paramount's D7 is a "derivative work" which means you own it but you cannot do anything with it without the permission of the original designer.

Scoutdad · Post by **Scoutdad** » Mon Apr 26, 2010 3:48 pm

Steve Cole wrote:Technically speaking, making your own copies of our miniatures (or any other company's miniatures) is and illegal copyright violation.

If you sell copies, you're doing to get found out and be in trouble. If you just use them yourself, you may not be found out but you are still breaking the law.

Making your own copies of your own sculpture is not illegal, but selling them may violate the copyrights of whoever did the original design (or the design you based it on). For example, doing your own sculpture of a D7 is using Paramount's design. Doing your own D23 design which is obviously "derived from" Paramount's D7 is a "derivative work" which means you own it but you cannot do anything with it without the permission of the original designer.

which is exactly why I limited by casting to making small items of my own deswign to sccesorize existing models/minis.
While a bedroll, ammo crate, or dunnage rack is easy to make/cast - it's kinda hard to violate anyone's IP if you just make generic versions.