How to Make Plaster Castings

Occasionally I find myself needing an artistic outlet. I don't remember where I first saw this technique but I was amazed at how detailed plaster casts could be if you do them right. I like 3D art best (mainly because I'm rubbish at drawing) and I thought I would have a go at making the most life like sculpture I could with casting hands in plaster.

Step 1: Make a Mold

The mold is everything. For this project, I used the gel that the dentist uses to make a form of your teeth called alginate. You know that goopy stuff they put in a retainer shaped dish that they put in your mouth and ask you to bite down on for a few seconds. It gushes out and around your teeth and sets up then they take it out and have a perfect mold of your teeth. I asked my dentist if I could buy some alginate from them and as it turned out, they had some old stuff they would just give me for free! My dentist even helped me do the first hand casting at the office. Make sure you have a container that's big enough for your fist. Mix up the alginate according to the directions that are usually on the container it came in. Usually it's just a matter of adding the right amount of water and mixing it in sufficiently. I've been told that using cold water makes the alginate set up slower than if you used warm water. Once you have the alginate mixed up, you need to work quickly before it sets up. Ooze your hand into the weird puddingy mixture and hold it still in whatever position you want. Just remember, some positions may be more prone to air pockets when you pour the plaster. 

TIP: I found it helpful to lube up my hand in Vaseline before putting it in the alginate. It helped me slide my hand out easier once the material set up. Also, it kept the alginate from grabbing the hair on my fingers and hand which would result in little chunks of the mold coming out on my hand. That would result in a imperfection in the cast. 

Step 2: Pour the Plaster

I just used Plaster of Paris. I'm sure there are better plasters that are more dense and could capture more details but Plaster of Paris is cheap and readily available so that's what I used. Just mix it up according to the box directions (again usually just involves pouring in the right amount of water) and pour it in the mold. I wanted to mount my hands so I stuck a dowel into the top of the mold, however when the plaster sets up, it tends to shrink a little which caused my hands to crack around the dowel. I'm not sure what the best solution is for this but perhaps a narrower dowel (mine was about an inch in diameter) would prevent cracking. Or, if you were very careful, you may be able to drill into the hand once it is set and then glue a dowel into the hole.

Step 3: Let the Plaster Set

Patience is a virtue.

Step 4: Remove the Cast from the Alginate

This shouldn't be too hard. The alginate should peel right off for the most part. You might have to use a toothpick or something to pick the alginate out of some crevices but cleanup should be relatively easy. Take some time to marvel at the detail of the cast. You can see every little wrinkle of your knuckles and every line of your palm. You can even see the texture of your skin on the cast.

Step 5: Touch It Up

Even with the Vaseline, I had a few imperfections on my casts. There were a bunch of little bumps, kind of like braille writing. I just used a dremel tool to grind off the bumps but you loose some skin detail this way too. If you're feeling adventurous, you could use the dremel tool to carve designs into your hands. I did this with one hand to make it look like you could see the skeletal structure. 

Step 6: Paint Them (Optional)

I decide to paint my hands because I wanted to use them as coat hooks and if I didn't paint them, i would get plaster dust all over my jackets. You definitely loose some of the more delicate details this way, but it protects the plaster from abrasion. If you want the best of both worlds, you could probably just give them a couple coats of clear spray paint.

Here are my hands:

-Me, the Sculptor