Learning from mistakes...

Based on ConocoPhllips data, we decided to focus on hand injuries for our first LiveDemo. There are a surprising number of hand injuries related to grinders, box cutters, and falling objects. Logically, that meant we needed to make some super realistic hands for use in demos. Unfortunately, there is little guidance on the web for such things (for good reason, I think). There began our adventure...

On a trip to Boston (on the way to my wedding) we decided to do some initial experiments with lifecasting. Our goal was to make a reusable mold through the following steps:
1. Use alginate to cast a one-time negative of a hand
2. Use a high strength resin to make a positive by pouring the resin directly into the alginate
3. Use the resin positive and plaster to make a reusable negative for later pouring a specially designed mix.

Interestingly, this is how crowns (for teeth) are made by dentists. This is where we got the idea.

The first two steps went very smoothly. Alginate is an interesting material. It is actually found in a lot of foods as a thickening agent. It is extracted from seaweed, absorbs water very quickly, and sets from a liquid to solid in a matter of ~8 mins. It is also safe for the skin and captures very fine detail on the surfaces to which it is exposed. It also smells like candy, which is cool.

This is what the alginate looks like when it has cured.
In this photo the resin has already been poured into the cavity

The resin, while volatile and quite noxious, was easy to mix and pours quickly. We poured the liquid resin directly into the void of the alginate mold and allowed the resin to set for about 1 hour.

This is the resin hand once the alginate has been stripped. 

After an hour, the alginate is stripped and...viola...an incredibly high detailed replica of a hand. The only problem: The resin hand is nothing like a human hand.

Now, for the problematic part. After a few tries we learned quickly that typical plaster will not work for making a reusable mold. The resin sticks and the plaster captures almost no detail.

Resin hand in plaster in our (failed) attempt to make a reusable negative.

We had to stop our experiment there. Since I was getting married in a few days, I needed to divert my attention to flowers, cake, and my fiancee!