Creating a Hand Casting

Sometimes it is necessary to have a casting of a hand created to send to an E-Nable volunteer or for someone that needs to have easier access to a child’s hand that they are trying to create a device for. Here are some basic instructions for those of you that may not have access to a 3D scanner and need to make a hand casting the old fashioned way!

What you will need:

  • Some kind of “Instamold” (we found ours at Michael’s Craft Store)
  • A package of strong cast plaster (again, at Michael’s Craft Store)
  • A bucket or mixing container
  • Measuring cup
  • Wire whisk
  • A container to pour the molding material in (we used an old oatmeal container, but make sure to use something you don’t plan to use again)
Follow the directions of the package of which ever kind of mold making materials you chose to work with.
Measure out the appropriate amount of power mixture and water ratios (you will have to do some math) and add the measured powder to a bucket.
Add the measured water to the bucket.
Use the wire whisk to stir thoroughly and mix well.
Pour the Instamold into the container that you have chosen to create the casting in - choose something that you will not need to use again (we used an old oatmeal container). Place the container into the original container you used for mixing the Instamold so that when the hand and arm is placed into the container to start the molding process, the excess materials can spill over and not create a mess.
Have the person that you are creating the casting of sit comfortably and find a solid and stable surface to place the container of Instamold on that will allow them to rest comfortably for the 10-15 minutes needed to create a solid mold of their hand. This is especially important for small children. The person must remain as still as possible for the mold to work and form properly and ensuring they are in a comfortable position while the mold is setting – is very important. We had Peregrine sit in a chair and used a step stool to place the container on so that his arm hung comfortably at his side.
You will need to use something to place between the arm and the mold material when it is time to remove the arm from the mold – as it will have created suction. We used a dull butter knife to slide in between the arm and the mold material to allow air to reach down into the mold and slide the hand out. You want to use something thin – as not to cut into or deform the mold while trying to remove the hand.
Once the hand is out – you will prep the plaster casting material. Follow the directions on the package.
After measuring your water properly, slowly add in the plaster powder a little at a time until you notice the powder is making “small volcanos or mountains” sticking up out of the top of the water.
Mix well.
Pour the plaster in slowly. Tilt the mold to the side while pouring the plaster inside to avoid creating bubbles.
Once your mold is filled completely, follow directions on the package as to how long to wait until removing the casting. Allow enough time for it to set completely. You don’t want to have to do this again!
We used a container that allowed us to tear it off around the mold and casting once it was ready to come out so that we could peel the mold off from around the hand cast instead of trying to pull it out.
And it’s out! Place somewhere that is open and will allow the casting to completely dry.