Speaking of Molding Problems / Questions

[niart17]

Since there is a vast wealth of experience and knowledge here, I figured I'd ask you guys how to best tackle this. I built this Alan Bean astronaut figure a while back in an attempt to learn sculpting techniques, and well I really like Alan Bean. (sorry for the not so good pics)

This is what's beneath the milliput sculpt.

At the time I was building it, I wasn't smart enough to think ahead and make it easy to mold and copy, figuring I would simply sculpt more if I wanted more. But now that I've finished, I'd like to be able to make copies of parts of this one so I can make others in different poses and perhaps different suit details. So my question, what are my options for making molds of this figure so I can resin cast parts to edit? I know obviously I will have to remove the hoses, back pack and the chest unit, that's not a problem. the problem is the way it was sculpted over an action figure as an armature in Milliput, I don't know if I can safely cut it into sections without totally destroying the original. Any ideas on how to best tackle this would be much appreciated.

Thanks,
Bill

 

[robn1]

Nice sculpt! The figure looks nothing like Alan Bean though

I would be reluctant to mold a finished piece but it can be done. A technique I've read about but never done is one piece split molds, where the original is place in a box and simply cast in a solid block of silicone which has to be cut open. Clear silicone can be used to make the master visible during cutting. There are some threads here that explain in more detail http://resinaddict.com/forum/

 

[rbeach84]

Aye, once you have a copy, even a rough one, you can use that as the basis for a new master... trick may be finding a compatible mold release agent (I suspect, for example, my favorite of Vaseline diluted with turpentine would eat up the paint job on your figure...) You really don't want to have the figure stuck in a mold only to end up picking bits of silicone from the original.

Regards, Robert

 

[niart17]

Thanks for the replies. I may have to try to do the one piece mold first. I'm not so much worried about the paint being messed up since I wasn't overly happy with the paint job anyway and the decals can be reprinted. My main concern was that I'd have to pull out a razor saw and cut off the arms to mold them separately from the main body. I was afraid if I try that the milliput will start crumbling away from the plastic figure and I'd never get it back right. It shouldn't hurt anything to try a one piece clear mold first I guess and if it doesn't work move on to plan b or c.

And true robn1 he doesn't really look much like Bean. Unless of course you squint really really hard and perhaps try a little of what Shatner is doing in your icon. Then he's a spitting image.

Thanks again guys. Hopefully I'll be able to try something soon.

 

[robn1]

If protecting the finish isn't a factor then you could imbed it in clay to do a two piece mold. It's just a matter of which tedium you prefer, claying it up or cutting the one piece block.

 

[rbeach84]

If the backpack and hoses are separate, then the basic figure itself should be relatively straightforward to, as noted, embed in clay for creating one half of a two part mold. You'd eventually want to have vents for the arms while using one foot/leg for the pour (the other could serve as another vent.) One thing with this is the expense of making a one part large enough to encapsulate the entire figure. Ideally, you'd want to use a 'strongbox' that would support a glove mold, allowing for easier removal of the cast piece. Essentially, you've have to coat the figure in a layer of clay of appropriate thickness for the type RTV being used for the mold, then treat the encapsulated clay/figure shape to a another claying to make a two-part plaster or fiberglass mold 'strongbox, then repeat for the other half of the strongbox, then remove one half of the encapsulating clay layer so to start pouring the RTV 'glove mold' halves...etc. More trouble, but more economical if you're going for higher production runs.

R/ Robert

 

[niart17]

Thanks for the help guys and perhaps I'm a bit slow on this so sorry if I'm asking dumb questions. But since the arms (especially his right arm) goes in front of the body, wouldn't that make a two part mold (assuming you guys meant front and back) not work? I just can't visualize how that would work with the arms still attached and it not trap the arms in place.

Bill

 

[rbeach84]

Bill, depends on how much overlap there is. That is one advantage to a glove mold - since it is relatively thin, it can be removed from some pretty complex shapes. I bet someone with more experience than I with different RTV's could recommend a good strong yet flexible formulation. Also, as long as you can apply some kind of constraining force, the mold can even have 'splits' cut into it to aid with removal. If you've even looked at some of the wonderful aftermarket resin detailing sets, there are things that are hard to believe could be molded, but it is all due to the flexibility of the RTV.

R/ Robert

 

[crackerjazz]

Hi Bill, welcome aboard! I've always wondered about the same thing -- thanks for the info, Robert!