Success! Making a reusable mold is not the easiest thing to do but we did it!

Our team of three embarked on a more informed journey to create a realistic hand. Using the knowledge gained from our first experiments, we attempted the following process:

1. Cast a negative using alginate
2. Cast a positive with resin (with a wrist this time)
3. Construct a plexiglas box
4. Cover the resin hand half with clay and install acorn nuts
5. Spray all surfaces liberally with mold release
6. Pour silicone rubber in the box to fill the container
7. Once cured, strip the box and remove the clay
8. Level all surfaces, spray with mold release, and pour again
9. Strip the form and yield 2 halves
10. Party

Here are some photos of key moments in this process.

This is our spread. all of the materials needed for the aforementioned steps!

Our team (Alex and Spencer) taking initial measurements

Mixing alginate. This is a 50/50 mix by volume water/alginate powder

Waiting...I had the pleasure of casting my hand in the alginate. It takes about 8 minutes to cure. In the meantime, you must be very still as the alginate/water mixture cures. I was nominated for this task because I have the smallest hands.

Aerial view of Spencer mixing resin. Yes, it was well ventilated!

Pouring the resin with high hopes.

High five! The resin cast worked...very well.

Trimming the excess resin from the wrist. It is strange to cut
a replica of your own wrist.

Resin hand in the Plexiglas box. This was uncharted territory.

Since we need two halves, we must cover up one half with clay before pouring the silicone mold. This was VERY time consuming.

This is the hand half covered in clay. The acorn nuts are to key the surface so the silicone halves fit perfectly when casting in the future.

The resin hand with clay and acorn nuts in the Plexiglas box.

Mixing the silicone rubber for the first half

Mixing parts A and B!

Pouring the silicone rubber...you must be very careful!

The hand once the rubber has been poured and the Plexiglass has been stripped.

We put the box back together, sprayed it all down with mold release, and poured the second half of the silicone rubber over the first half (resin hand stays in place)

This is the final block. It doesn't look like much but...

Once you separate the two halves and the resin hand, you can see that this is a reusable silicone mold. The acorn nuts can be used to help line up the halves. If you look closely, you can see the funnel we made for pouring. The whole purpose of this mold is to be able to later skip the alginate steps and pour many exact copes of a hand for demonstrations. This is important for demos that are aimed at showing the difference in injury with and without gloves, for example.