This past month, our cosplay group taught a crash-course in headcasting. There are several ways to make molds of humans, one of the most cost effective ways is to use a combination of alginate and plaster of paris. A special thanks to Maggie Bennett resident sculpture for a wonderful workshop, Sergei and James for photography, and Jenn for modeling. It's a bit more difficult to buy the exact amounts you'll need, so most of the stuff you'll end up buying will be akin to the "party size" versions from Sam's Club or Costco. You may as well make a party out of it, since the smallest size containers of the materials will usually be enough for 5-6 people. Most of what you'll need is about $60, so one person would be $60-100, if you have 6 people it's about $10-15 per person. Bring friends. Maybe beer. Definitely movies.
You will need the following:
8 oz super alginate (A 3 lb box on Amazon will run you $30ish)
Plaster of Paris Gauze (You need roughly 1-2 rolls per person. A case runs $12-20 on Amazon)
Gypsum Cement (We used Ultra Cal in this one, which can be found here Ultra Cal 50 lbs bag for $36 plus shipping, any gypsum cement or plaster of paris will work. Here's one on Amazon that's more expensive per pound, but a smaller amount.)
Optional: Wig Cap (Any party store or wig shop should have these for cheap. Also, Amazon $2-3)
Trustworthy friends. This is a group effort.
Step 1: Prep: Get Your Hair Ready
Do the "do." Plaster and hair generally doesn't mix. So, put Vaseline or petroleum jelly in any facial hair you have. (Eyebrows, beard, moustache, etc.). For short head hair, you can put the jelly in that too. A scull cap will work for longer hair, or short hair if you prefer that.
Anything you don't get covered or jellied will likely pull out a-la bandaid. Good luck!
Step 2: Prep Part 2: Cut Your Plaster of Paris Gauze Into Sections
Plaster of paris gauze normally comes in rolls, cut yours up before you get started into 8-12 inch sections. Less mummy and more craft project. Shorter strips will make it easier to handle and much easier to correct mistakes.
Step 3: Prep Part 3: Trash Bag
After you get your hair and wig cap, you can opt to protect your clothing with a trash bag if you need to. You can also use a disposable poncho if you're more fashion conscious...
Step 4: Create the Dividing Line in Your Mother Mold
After getting your or their face and plaster ready, have the victim...erm, I mean "castee," sit down to make the mother mold. Mother molds are cast in 4 basic parts: the dividing line, back plaster, front alginate, and front plaster. First, you want to make the dividing line which will separate the front and back.
Get a bucket of warm water, put on a pair of gloves to protect your hands, then dip one of pieces of gauze in the warm water. Fold it in half create a line over the top of the head and behind the ears from one side to the other. You will need to build up a layer (we did 3 layers). Make sure to smooth the layers of gauze together with your fingers. You should place extra behind the ears to help support and build them up.
The ears are the most fragile part of the process.
Step 5: Make the Back of the Mother Mold
After you make the dividing line in your mother mold, fill in the back with plaster of paris gauze, working from side to side. Dip each piece of gauze in warm water, wring it dry, and then put it on the back, building it up. You generally need 3-4 layers to create a solid back. You can wrap the back of your mold with knuckles to see if you're done. It will make a thunking sound like a ripe watermelon. Allow it to cure for 15-20 min before starting on the front.
Be careful to wear your gloves the whole time. Plaster's easy to get off your hands, but if it dries, you'll need to chip it off.
Step 6: Make the Alginate Front to the Mother Mold
This part goes REALLY fast. So read this a few times before going through the step.
Get a new pair of gloves and a few tongue depressors.
Take 8 oz of alginate dry powder and mix it 1:1 with warm water. You can use a mixer to mix it evenly.
HAVE THE MODEL CLOSE THEIR EYES and relax their face. The face they're making is the face the mold will have. Clean out the model's nostrils as you go. It's important to make sure the model can breath. Straws can work and are useful, but make sure you have steady hands so as not to hurt the model. I'd say vinyl tubes would be a better bet.
Now, carefully pour the alginate down the front of the model's face from the divide line forward. It will drip down their top, simply scoop it up and place it back on the face. The ears and nose tend to be particularly fragile. Don't freak out, just keep lifting and scooping until it sets. It will eventually start solidifying, just keep scooping and dropping it back on the face. Eventually the model will look like a Lord of the Rings goblin, but we won't hold that against them. Make sure you get pictures so you can embarrass them later.
When you get close to done, stick a couple small pieces of dry gauze in the alginate to help bond the two layers together.
Step 7: Finish the Mother Mold Front in Plaster of Paris
Alright, last step to the mother mold. You're nearly done, just be prepared to sit for a while.
Wait 15-20 min after you finish with the alginate to make sure it's set. Get a book on tape, some good music. Just make sure your model doesn't laugh, it'll give their mold a permanent grin.
Get a new fresh pair of gloves and another warm bucket of water for the plaster gauze. The last bucket is probably cold by now.
Start slowly working to cover the alginate front in plaster strips to help protect it from damage. You need a light touch to keep from squishing any details while at the same time you want to support weak points like the throat, ears, nose, and chin. Make sure to smooth the layers on as you go until you've built up several layers so it's hard and firm like the back.
Make sure to preserve the divide line for when you crack the mold apart. Cutting plaster casts is better left to doctors, don't try it at home. Keep the divide line clear.
Wait 15-30 min until it sets. It will look dry before it actually is dry. Rap on it with a knuckle to test it. When it sounds solid, it's probably ready to come off. You can tell the model you're knocking to see if there's anyone in there.
Step 8: Break the Mother Mold Apart
To remove the front mold, use something thin and pliable to work under the lip of the break line. Pull it forward from the top and let it fall forward and down with someone to catch it. You can make touch-ups at this point, but it should look pretty good. Also, remember to let the model breathe.
The rear of the mold should just come off. You have less to worry about preserving the integrity of this part, but still be careful.
Step 9: Cast the Face From the Mother Mold
Alright, home stretch. You're almost done and the model is free to help now.
Reassemble the mask, grab a new pair of gloves and go.
Lightly coat the inside of your mask with Vaseline. A light bristled brush can help with this, or a sponge. Make sure it's an even coat.
Mix the Ultra Cal in a cup with warm water in a 1:1 ration. Using your fingers carefully spread a thin layer through the inside of the mask, be extra careful with the fragile parts like the ears. If your fingers aren't delicate enough, you can use a brush for the first part. Make sure it gets in all the small, thin areas otherwise it won't be a full mold.
After you have the first layer on the inside, start dipping the plaster of paris in the ultra cal mix to build up the strength of the piece without adding a lot of weight. It's much easier to work this way.
Allow to cure at least 1 hour in a cool, dry area. A full day (24 hours) is a safer bet if you want to make sure it sets well.
Step 10: Break Out Your Piece
Once you head has cured, break the mother mold. You may have to tear it to get it apart. The mother mold is disposable and one-time use. So, make it count!
Step 11: Repair/Finish
Once you piece is out, you may need to do repairs/edits. You can add any pieces you need to by simply worked more ultra cal on the piece or sand and buff off extra parts. A lot of people had plaster nose boogers; a knife and some sand paper cleared that up.
Happy head making!
Note: If you leave the head sitting out somewhere. Make sure you leave a hat on it so when friends visit you and see a mold of your head somewhere, they won't think it's odd because it's wearing a hat!