Waste mold casting

[ArtsyLynda]

I don't know why they're calling Danny DeVito's foot a 'troll foot" but The Compleat Sculptor did a mold and casting of it on camera. The video is here. If you've never seen waste mold casting, this may be interesting to you. I don't do this kind of casting - I try to keep my molds intact so I can use them again! This is what you do if you want to do a one-of-a-kind casting as they did here. http://backstage.andersoncooper.com/post/18602236822/danny-devito-troll-foot-making-of

[JMM]

Hey ArtsyLynda,
This process also be termed "life casting." Alginate is used for this type of casting as seen in the video and is water based. If the model surface to be molded is not human skin then a separating medium must be applied to the model surface otherwise the alginate will stick and tear with demolding. Waste molds can also be made of plaster and plaster can also be cast into the mold. With a thin pigmented surface layer on the casting, the mold is chiseled from it. Plaster molding is very time consuming and very messy!
Thank goodness for modern mold materials!

JMM

[ArtsyLynda]

Thanks for the explanation! I haven't done any of this kind of work (obviously) and I thought it was interesting to watch. I would've preserved the mold to do other castings - the site of Mark cutting it into tiny pieces was a bit unsettling! LOL

[JMM]

With alginate molding there is no chance at preservation. Within a short amount of time (hours) the mold will dehydrate, become hard and crack and pouring plaster into the mold will also cause dehydration to where the mold is useless for more pours. Placing it in water will rehydrate it but not to where the mold was originally.



JMM

[ArtsyLynda]

Thanks a lot! I use silicon rubber molds that are a different color than the one shown, but that looked as rubbery as the molds I use, so I didn't know it couldn't be reused. Thanks for explaining!