A few Halloweens back I had need for a life size bright green skeleton torso (as we all do at least once in our lives.) I checked around online but the cheapest ones I could find were $30-$80, plus they looked kind of dorky. The skele was just one part of a larger decoration project so I couldn't justify spending that much on it.
I didn't have much cash on hand, but I did have some basic crafting supplies and the time to make something unique. This Instructable will detail the process of building this mean green bone machine, and my experience using drywall compound for mold making.
Materials and Tools
Acrylic Paint / Spray Paint. Plenty of black and white, and other colors of your choosing
String, general purpose
Human Skull (plastic replicas are an acceptable substitute)
Insulation foam in a can (Great Stuff)
Dry Mix Drywall Compound
Cheese Cloth / Medical Guaze
Elmer's Glue (white glue)
Hot Glue & Gun
Paint brushes, 1/2 to 2 inch wide
A plastic tub to mix the mache' in
Plastic Tarp to work over
More time than money
Step 1: Plaster Molds and Foam Skulls
Why drywall compound instead of the traditional plaster of Paris? There are some very good reasons for this:
- Drywall compound is cheaper than plaster
- It isn't as dense as plaster and is easier to carve and break away unwanted bits
- It takes longer to become completely solid giving you more time to work with it
As soon I was finished with the molds I threw them away, I didn't feel the slightest bit attached like I would have if I had put a ton of effort into them.
* I didn't take many pictures of my original skull molds but I am making some more this year. I will add pictures as I make progress.
Making Plaster Molds
- Get a plastic skull, a 12"x12"ish piece of plywood, and a bit of clay. Most any non-drying clay will do.
- Drill a counter hole into the bottom of the plywood and follow it with a smaller hole drilled all the way through. The second hole is only large enough to let the threads of the screw through, the larger hole lets the head of the screw sink into the wood leaving a flat bottom.
- Drill a hole in the bottom of the skull with an even smaller bit, the screw will need to bite into this pilot hole.
- Screw the skull securely to the board, tight enough that it doesn't spin.
- Fill the recesses and holes of the skull with clay. These undercuts would keep the skull stuck in the plaster when the two halves of the mold are separated. Although it is fun smashing a mold off of something, it isn't very productive.
- Build a dam of clay around the center of the skull as seen in the above images. This wall of clay will be the dividing point for the two halves of the mold. Add "keys" to one side of the damn by adding hemisphere chunks. Later on the impressions left by these keys will help align the two halves of the mold.
- Paint petroleum jelly over the entire surface of the skull with a paint brush (the brush will never be the same, use a disposable one.) You want a thin layer of jelly over the entire skull, try not to leave big gobs of the stuff and make sure to get into the little nooks and crannies. This jelly will keep the drywall compound from sticking to the skull
- Mix about a cup of dry compound with about half a cup of water in a plastic tub. For the first few layers of the mold you want the mix to be pretty runny so that it can get into the details. Mix and add water or compound until you get a consistency like pancake batter.
- Slap that batter on yer skull. Be as messy as you like but try not to get any over the top of the clay wall. Let the batter dry until it starts to harden and then add another layer of fresh mix. Repeat this step until the mold is about 1/4 inch thick.
- If you tried to pull the mold off of the skull now the drywall compound would crack into pieces, but if it is reinforced with cheese cloth it will be much stronger. Cut some pieces of cloth into squares large enough to cover the face of the skull. Dip these into some fresh drywall batter and lay them onto the top of your mold. Let this dry for a few minutes and then add another thin layer of batter. Keep adding layers of compound and cheesecloth until the mold is about 1/2 inch thick.
- Prep the un-mudded half of the skull by removing the clay barrier and add some little clay wedges to the side of the plaster. These will leave indentations in the mold that will make prying the halves apart much easier later.
- Slather the exposed skull and the drywall seam with more jelly.
- Repeat the drywall compound steps used to create the first half of the mold. Do not get plaster over the top of the first half of the mold or the pieces will stick together.
- Unscrew the skull from the board and use a flat head screwdriver to dislodge the skull from the mold. Now the chances are that it wont want to come out without a bit of persuasion. Since the mold doesn't need to be a perfect replica, it is fine to be rough with it and crack it in a few places. The better job you do of filling in the undercuts, the easier it will be to separate everything.
- Spread petroleum jelly on the inside of the drywall mold and strap the two sides together with rubber bands.
- Use a can of insulation foam to fill the mold. Start at the bottom and swirl you way up around the sides, don't put it in too thick or it will have a hard time curing. You don't really need to fill the center of the skull, but if you do give the foam around the edges an hour or so to cure and become solid first.
- After letting the foam solidify, take off the rubber bands and pull the mold apart. Some tugging may be needed to free the foam.
- I painted the skull for the skeleton white and then green, but I also made some blackened ones. To do this mix some black acrylic paint with water to this it down to a cough syrup consistency. Use a thick paintbrush to cover every single bit of the skull, inside the bubbles and cracks, everything.
- Mix some black and white paint together to get a dark grey and drybrush this color onto the skull by dipping the brush in paint, wiping most of the paint off on a paper towel, and then brushing it over the skull. The ridges and texture of the foam will pick up the paint.
- Mix a lighter shade of grey and drybrush the skull again. Repeat as much as you like. I haven't tried but I bet some red meaty skulls made with this method would look cool too.
- Some of the skulls I made had their bottom jaw removed with a hack-saw, you know, to mix it up a bit.
Step 2: Stick and String Bones
The process here is to get some sticks, straight-up from-a-tree sticks, and lash them together with string and Elmer's Glue (dead tree limbs are the best way to go.) The trick to this is in the execution, eg.picking branches that look like bones, and building up string to make knuckles and joints. Absolute precision isn't necessary though, when the pieces come together they can't help but look skeletal. Best of all the arm is semi-flexible thanks to the rats nets of string and glue.
Making Bones from Sticks
- Your gunna need a hacksaw and some branches ranging from 1/4" to 1 1/2" diameter.
- Cut/break the branches up into arm bone size pieces, use your own arm for reference.Notice in the main picture here how the parts I chose for the forearm (the ulna and radius) are slightly curved giving them an especially boney look, try to get some like that. The fingers can be as straight as you like.
- Get some reference pictures of naked hand (at scale if you can).
- Take some $1 spool of string and start wrapping the stick bones together until the fingers want to fall apart. Feel free to use little dabs of hot glue to help hold it together, but not too much.
- Saturate the wrapped string with white glue. Use your fingers to spread it around with your fingers and make sure it gets down in the string real good.
- Wait for the glue to dry, peal the glue off of your fingers for fun.
- Wrap more string around more sticks and use more glue until you have a hand. Use little chunks of stick about 3/4" long that have been wrapped up and clued to make the wrist bones (don't remember the names this time.) These chunks can then be lashed to the fingers to fill out the palm and wrist. Again, don't worry about being perfect. No tricker-treaters are going to walk up and call you out on the placement of your pinky bones.
- Strap the hands to the forearm by looping around one and then around the other in a revolving figure-eight pattern. You will be able to tell if the joint is secure just by how it feels when you flail it about.
- If you bones are stubborn and won't come together easily you can use a needle and thread to help strap everything together.
Step 3: The Ribcage - Paper Mache' & Wire
The best advice I can give is to follow your reference pics, and to mash and bend it until it looks right. I think the end result looks close (enough) to a ribcage and it is ridiculously sturdy. This is also an excellent opportunity to make a decent sized mess with paper mache', if you're into that sort of thing.
Making a Wire and Mache' RibCage
- Again, reference pictures are your friend. Borrow someones ribcage and use it as a study model, or use pictures.
- You're gunna needs some nice heavy work gloves and a pair of wire cutters. The gloves protect against cuts and scrapes, and your hands won't ache so bad after bending all the wire.
- Bend and twist a few bits of wire together to make a spine then another set for a sternum
- Cut lengths of wire for each set of ribs and connect them in a skeletal like fashion to the to the pieces from step 3
- To help the ribcage hold it's shape, use a thinner wire and paper mache' to secure the joints
- Add a collar bone with more wire and mache'
- Cut shoulder blades from some heavy paper or cardboard and give them some definition with more paper mache'. Use some hot glue to add these to the cage.
Step 4: DIY Reconstructive Skeletal Forensics
Final Construction and Painting
- String the ribcage up to make it easy to work with. Place a plastic tarp underneath to catch paint and glue.
- Tie all the pieces of the skeleton together with more wire, string and glue.
- After the string dries, lay down a base coat of white acrylic paint. Spray paint can be used but it would melt the foam skull; paint the skull with acrylic before spraying it.
- Paint the skeleton with the color of your choosing or leave it white. I opted to paint the insides of the eye sockets and the underside of the jaw black, this helped define the shape of the skull.
Step 5: Built for Action!
This green guy has been around for the last few Halloweens at my house and I plan on using it again this year. Considering what it is made of, this prop has stood up to a fair amount of punishment and is still presentable. While revisiting this project I dropped by the pharmacy and saw that they had some decent full size plastic skeletons for only $30. That's a reasonable price and it now I think it may make more sense to just buy one of those the next time I need some bones. I am certain, however, that just buying it wouldn't be as fun as making this skele was.
All told I think this skeleton cost about $15 to make, and I got a few more skulls out of the can-o-foam on top of that. The next time that I need a torso I will use this method again. I've also thought about making the whole thing out of wood and string and presenting it as some kind of artistic metaphor highlighting the conflict of man vs nature. That, and hiding it behind the shower curtain to scare people on the john.
On the topic of more skulls, I've added some pictures of what became of them. I painted a few black and dry brushed them with lighter colors and that worked pretty well. Another had wings made with the same stick and string method used on the arms. Pantyhose were stretched over the skeletal wing and then nicked with a knife. The whole thing was then saturated in paint, giving the wings a leathery texture.
Thank you for checking out my project! I hope this Instructable inspired you to craft some creeps of your own using whatever you have on hand. There is a lot of freedom that comes from working with cheap materials; mistakes cost next to nothing. I encourage you to give it a shot and make sure to experiment!
Finalist in the
Halloween Decorations Contest