TechShop held a lifecasting class. I had already built a 3rd hand out of a few 2x4's -- see:
This time, I thought that I would try something with some additional "personality" -- I'd wanted learn a different method to make a 3rd hand ;-)
Step 1: Mix the Silicone and Apply
Use Body Double® Skin Safe Lifecasting Silicone Rubber fast set and dole it out with a tongue depressor into paper cups about 1/2 full. It is a two part RTV product, so when you are ready, mix the green and blue thoroughly.
Put a 2 foot square of brown butcher paper down on a table so that you don't mess up the table during this process. Place your hand firmly on the paper, and use a Popsicle stick to apply a "beauty coat", a thin coating to the hand. That will allow you to pick up all of the detail. Once the first coat is on, slather the rest on so that your hand is covered.
Wait about 20 minutes for the "fast set" to set.
Step 2: Make a Plaster Cast of the Back of the Silicone
Have someone cut Medical Grade Plaster Bandages into 1 foot long strips. Wet them in water and then apply them to the back of your hand.
Build up about four layers and wait about 30 minutes for the plaster to dry. You need the plaster to support the silicone when you want to pour the cast.
Step 3: De-mold Yourself !
The next thing to do is to lift your hand and pull it away from the brown paper. This is easier said than done since you have spent about 40 minutes in the same place and your are is now tired ;-)
After you lift off of the paper, you can take the plaster off of the silicone. Next, remove your hand from the mold. It will come out with a little bit of pulling. Although the silicone looks wet, it is dry and set-up.
Step 4: It's Time to Bloom!
Take some clay and create a dam where your wrist was so that you can fill up the mold with 300 Bloom Gelatin. You mix this stuff with glycerin, so make sure that you don't ingest it, otherwise, you'll spend a lot of time on a toilet. It is cool at room temperature, so all you have to do is heat it in a glass bowl to about 120 degrees in a microwave.
After that, pour it into the the mold. This is why you need the plaster -- it provides the support for the silicone -- otherwise, it would just move around.
Step 5: Un-mold and Enjoy
Let the 300 Bloom gelatin cool overnight undisturbed. After that, you can un-mold it as is shown in the youtube video.
Now you have an extra hand or two to help out on projects or to scare the crap out of people.
I made it at TechShop!