These instructions will allow you to make a silicone-encased Stop the Bleed training moulage leg for use in building a training kit for Stop the Bleed.
Things you will need:
1 inch diameter PVC pipe
Gold's Gym dense foam roller (6-inch diameter, 30 inches long)
Ecoflex 00-30 silicone made by Smooth-On
Silc Pig in fleshtone
Ultimate Wound kit - contains sample size pots of Silc Pig in blood and other useful colors
a bunch of wooden paint stir sticks
Sil Poxy (1 tube)
large glass or plastic container
5/8th inch wooden dowel
sheet of #2 HDPE plastic, about 0.033 inch thick
sulfur-free clay (such as Craft Smart Plastalina modeling clay), preferably in a neutral color
Step 1: Make the Core.
Measure 15 inch length on your PVC pipe. Using a hacksaw, carefully cut your PVC pipe to the desired length.
Measure a 15 inch length for the foam core. Using a hacksaw, carefully cut the foam roller to the desired length.
Find the center of each end of the foam roller. Using a 1.5 inch drill bit, drill into each end of the foam roller. Take care to remain perpendicular to the end. You should be able to drill nearly to the center of the roller on each end. Use a long, blunt instrument (we used a frosting spreader) to dissect around the plug of foam left in the middle. Once detached from the sides, it probably can be pushed out with the PVC pipe. Save the larger chunks of extracted foam. You will use these to plug the ends of the PVC pipe.
Once the foam is cored, the PVC pipe should slide nicely into the foam core. Squeeze down the foam remnants and pack them into each end of the PVC pipe.
Step 2: Make Your Mold.
For our moulage legs, we planned for 1/2 inch of silicone to surround our core. Upon measuring our foam rollers, the diameter was more along the lines of 6.5 inches. So, our diameter with the silicone added would be 7.5 inches.
To calculate what size rectangle of plastic we would need, we calculated the dimension of our end product. The circumference of our final product would be 2 x 3.14 x 3.75 in (=23.55 inches). (C=2 x pi x radius) The length of the foam core (15 inches) plus the silicone (1/2 inch on each end) would be 16 inches. Our piece of plastic needs to be these dimensions (23.5 in x 16 inch) plus some extra length and height to allow for overlap and head space.
Create the walls of the cylinder using a sheet of #2 HDPE plastic. We found a local plastics company and were able to purchase a sheet of the type and thickness of plastic that we needed from their remnant pile, which saved us a LOT of money on a custom cut sheet. Prepare the sheet by making sure at least one long edge is cut perfectly straight and perfectly perpendicular sides for consistent diameter all the way up the cylinder. Mark the circumference distance along the long edge of the rectangular. Roll up the plastic rectangle to the marked circumference measurement. Secure the edge in place as neatly as possible with duct tape. Tape inside and outside. For structural strength, add duct tape to the outside around the circumference of the tube at several levels.
Using sulfur-free oven-bake clay, knead the clay until soft, and roll it out. Check that it is level in all directions. Embed your plastic cylinder into the clay, and check that the plastic cylinder is perpendicular. I recommend placing the clay and mold on top of some paper or even some leftover plastic sheeting to protect the surface on which it will be sitting.
Your mold is ready!
Step 3: The First Pour of Silicone
Smooth-On Ecoflex 00-30 silicone comes in two separate containers (part A and part B) and must be mixed in a 1:1 ratio before use. I recommend using a utility knife to cut to lid at the notches and investing in a $2 bucket opener to make your life much easier.
To calculate how much total silicone you will need, calculate the volume of your final product minus the volume of the core. The volume of a cylinder is the area of the circle (pi x r squared) times height.
For the first pour, you are essentially pouring a 1/2 inch tall cylinder. Calculate the volume of your end cap. In our case, our diameter is 7.5, so the radius is 3.75. Our height is 0.5 inch. So, 3.14 x 3.75 x 3.75 x 0.5 = 22 cubic inches.
The Smooth-On website has a calculator for the casting volume. Convert the volume calculated into pounds using their calculator. If you get a decimal, you might need to calculate the number of ounces from the decimal (ie, 16 oz x whatever decimal of a pound you got). I HIGHLY recommend that you measure your part A and part B by WEIGHT not by volume. You can get much more precise with weight. We used a scale (nothing fancy - same scale we use when my son makes his Pinewood derby cars) and protected it from drips by covering it with plastic wrap or wax paper.
Place your container and then zero out your scale. Carefully ladle out (use separate ladles for parts A and B) or POUR each part of the silicone into your container. Add Silc Pig in fleshtone - a little goes a long way, but I encourage you to go for fully saturated color in order to hide transition points between pours. Stir the two parts and pigment together well with a wooden paint stir stick. Pour the silicone in a slow, thin stream into the bottom of the mold. The thin stream allows for any air bubbles in your mixture to pop and come up the surface easily. Scrape out as much of the silicone as you can from the container. Let that first layer set for about an hour.
Step 4: The Second Pour of Silicone
Do your math for this second pour ahead of time. Total volume of silicone needed minus the volume for your base minus the volume for the cap. The cap volume will be the same as the base, but with volume to fill about 1/2 inch under of the top of the core.
I recommend that this next step be done with at least two people - one to mix and pour the silicone, one to deal with preparing, placing, and holding the core in place.
Prepare your silicone. Again, measure your volumes for part A and part B by weight. Remember that whatever weight you need (for example, one pound), you will measure out 1/2 that volume (1/2 pound) for part A and 1/2 of the volume (1/2 pound, for a total of 1 pound) for part B. Add enough Silc Pig to saturate the color. Mix well.
Prepare your core. Put on gloves, and wear a respirator. If possible, step outside or into a well-ventilated space, as Sil Poxy has a strong, noxious odor like super-concentrated vinegar. Dot the sides and ONE end of the foam core (with the PVC pipe and foam plugs in place) with Sil Poxy. This will allow the silicone to stick to surfaces (like the foam) that it would not normally adhere to. Use your gloved hands to spread the Sil Poxy over the sides and one end of the core. I found that once your spread it around a bit, you can pat the surface with your Sil Poxy-covered gloved hand to thoroughly coat the surface.
Carefully place the foam core into the mold with the untreated end of the core facing up, centering it carefully over the silicone base. I used three short lengths of wooden dowel inserted between the core and the mold to help with spacing and keeping the core centered.
While you hold the core in place, a second person can carefully pour the prepared silicone in a thin stream into the space between the plastic cylinder mold and the foam core. Fill until the silicone is about 1/2 to 1 inch shy of the top of the core. **You will need to hold FIRM pressure on the foam core, especially once most of the volume is in. I recommend standing over the mold and using your body weight to press your gloved hands down on the foam core.
**Our first attempt at the leg failed, because we did not take into account the the foam core would FLOAT in the silicone. When we tried to press it back down into the liquid silicone, our mold push off our shallow layer of clay and silicone went everywhere. Tragic and expensive.**
Here's where it gets really fun. Whoever is holding down that foam core will need to continue to hold constant pressure until the silicone is fairly set.....so about an hour. I recommend turning on some 80's music and belting out your favorite retro tunes. We tried stacking weights on the core - we had twenty pounds on there and had no more room, and it wasn't heavy enough. If someone out there can calculate exactly how much weight would hold down the core and be able to fit something of that weight into the top of the mold, I say go for it. For our purposes, an adult with the strength, body weight, and patience to hold that core down for an hour was our method.
After the hour, the silicone will be set enough to allow you to pull out your wooden dowel spacers and place some weights on the core for the remainder of the cure time. We cut out a little circle of our #2 plastic to put down on the top of the core under the weights. The cure time for the silicone is 4 hours, but we left them overnight for good measure.
Step 5: The Final Pour of Silicone
For the final pour, remove the weight and if you had one, the plastic circle on top of the exposed core. Prepare your foam core by putting Sil Poxy on the exposed end of the foam roller (remember: gloves, respirator, ventilation). Carefully apply Sil Poxy with a cotton swab to the sides of the foam roller still exposed and the surface of the cured silicone from the second pour. Take care to avoid applying the Sil Poxy to the plastic sheeting, so that the silicone doesn't bond with your mold.
Prepare and tint your silicone as before. Pour in a thin stream. If you did your math correctly, you will have 1/2 inch of silicone over the end of the core, and the entire core should be encased in silicone on both ends.
Let it cure. See you in at least four hours.
Step 6: The Macabre Art of Moulage
Unmold your silicone cylinder. You will have to un-tape your plastic mold and gently tip the leg off the clay base. CAREFULLY, separate the silicone off the plastic mold. It's not supposed to stick, but it's not like it slides right off. They do sell a mold release spray that might make things easier. We just didn't use it.
Because these are handmade legs, they might not be perfect. And, the silicone will reveal every imperfection of the mold - so any irregularities on the surface of the plastic, the strip of duct tape down the length of the mold, it will all show up. Place your unmolded leg onto clean, white paper (newspaper will transfer ink onto your silicone).
So find your prettiest sides. Stop the Bleed trainer legs typically have a laceration and a gunshot wound entrance and exit wound. Decide where your wounds will be. Using a utility knife or Exacto-knife, create your laceration. A sharp, round punch tool can be used to create a neat entrance wound. The exit wound should be a larger, irregularly-shaped wound on the opposite side from the entrance wound. You might want to trim a narrow border off the edge of your laceration. Or not. Designer's choice.
Next, carefully pull open each wound (the Ecoflex 00-30 is very stretchy) and use a utility knife and some scissors to cut away some of the foam under each wound. This space will allow a learner to practice "packing" the wound with gauze.
Finally, add some blood detail at the "wound" sites. If you are making multiple legs, you can use the small amount of leftover silicone coating the mixing container from another leg build and mixing in some blood Silc Pig (from the Ultimate Wound Kit). Use a gloved finger to spread a small amount of Sil Poxy around your wound sites. Allow the blood-colored silicone to set just slightly so that it is not runny. Dab it onto the Sil Poxy coated areas with a finger or a small, cheap paintbrush that you don't mind ruining. You can even apply Sil Poxy and "blood" silicone to the inside walls of the wound for greater effect. Allow the blood details to cure for the minimum four hours.
Step 7: Clean-up
For spilled prepared silicone, just let it stay where it's at. It will cure and peel away in a super satisfying way.
For unmixed silicone (part A or part B)...
First, it can make your floors extremely slippery. And it is "oily" so it does not wash away easily with plain water.
If you can mix A&B together and let it cure, that will make your life easier (eg, your ladles that you used for scooping silicone)
If you need to clean up unmixed silicone, do NOT wash it down your drain. Using paper towels, wipe out containers, utensils, etc., and throw away the paper towels.
For table tops, use hot water and A LOT of Dawn dishwashing liquid. A scrubber sponge with lots of Dawn on it can help get up all the slick silicone residue.
Exercise prevention by putting down lots of newspaper onto your work surface, covered by plain white paper to prevent ink transfer to your moulage legs. That paper can't be recycled afterwards. Unfortunately, it needs to go in the garbage.