I've been asked to help make a resin mold of half of a cow carcass:
My biggest question: how do I seal the flesh before I put silicone on it? Should it be frozen or thawed? I can forsee the frozen carcass as a problem while it thaws and releases moisture.
Has anyone had experience with masking a cast of something like this?!
Not sure if this will help at all, but here's a video of someone molding a dead fish: How It's Made - Fish Replicas - YouTube
the question is, do you want it to stay edible or do you just want the cast?
only thing i could imagine to make it stay edible is vacuumforming and then add fiberglass to the form from the outside to make it stiff.
every other method makes the mold smell like death or ruin the meat
but if the meat doesnt matter, just seal it with somekind of cyanoacrylate adhesive so it doesnt leak then cast as usual (would ruin hundreds of bucks worth of meat thou)
Some poor animal had to die for it so I think wasting meat is a crime. Can't you just cover it in alginate like you would do someone's head?
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The cheapest, easiest and safest way to do this is to lay it flat, and mold it with alginate, then do a fast shell/mother mold with burlap and hydrocal plaster, just two layers, add some 1x2"s along the the length for support and attach them with burlap strips soaked in plaster.
Carefully remove the mold, you don't want to rip the alginate! then cast a hydrocal positive backed with burlap then wood structure for support.
Once that is set demold and fix any defects with clay. Apply a thin coat of paste wax, let that dry then a coat of vaseline and make your silicone mold at your leisure without ruining that side of beef!
If you don't care about the beef, let it warm up to room temp, apply a thin coat of vaseline to the beef and mold it with a Tin Cure (Condensation Cure) silicone like 1065 or GI1000, use the regular catalyst and enough Ultra Fast catalyst to give you a 20 minute working time, the faster the cure the less chance for any inhibition get some help to paint it on thin and fast. Do two coats like that then add some thixotropic agent to thicken the silicone and build up to a usable thickness then do a fiberglass mother mold.
The method described by Ralis works just fine with the alginate. I worked on a pigs head that was cast that way and worked well.
Thank you Ralis! That's exactly what I needed to know. The company doesn't care about the carcass in the end - they just need a hard casting. Thanks again!
One more question - since they want both sides done, would it be best to out shims all around the outside, mold one side, wait for it to cure, then do the other side?
Also, I am thinking it would be easier to mold it hanging from a hook instead of flat on the ground?
the water from being frozen won't inhibit the alginate ?
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