Noticing that my breasts provide a source of comfort for my partner, I decided to take matters into my own hands and make him a personalized version of a classic erotic novelty: a squishy boob-shaped stress relief toy, modeled after one of my very own. Maybe now he'll leave me alone so I can get important things done.
This is the second part of a two-part series on making a silicone model from a human body part. The first part of the series was Replicating body parts in plaster.
Step 1: Go Get the Stuff You Need
You will need:
- 1 pint of Dragon Skin Platinum Silicone Rubber
- 2 pints of PMC-744 Urethane Rubber (although, considering this triggered an extreme allergic reaction in both my assistant and I, I'd recommend using Rebound 25 silicon rubber, if possible)
- Smooth-On Universal Mold Release
- Ease Release 800
- Shellac or lacquer sealant
- 2 two-pint measuring bowls
- 2 cheap paint brushes
- 2 wooden mixing sticks
- a plaster cast of a breast
- a white painter's body suit
- a pair of thick rubber gloves
- a pair of nitrile gloves (non-latex)
- a couple of thick garbage bags to dispose of chemicals
- an empty 2 gallon water container
- a razor blade
- a hot glue gun
- duct tape
***a well-ventilated area or a nice, windy spot outdoors***
Step 2: Seal the Plaster
I did mine a little backwards (built a frame around it and then coated it), but before you figure out a way to house your plaster model, you should seal it with shellac or lacquer. Apply a few quick, thin coats until it is completely covered. It's best to use something that is colored so that you can see whether or not you coated the whole thing.
Once the sealant is dry, spray the inside of the rig with Universal Mold Release agent. Gently spread the release agent around with a paintbrush and then let dry for thirty minutes.
Step 3: Build a Frame
To make a pour mold around the breast, you are going to need a frame built around it into which you can pour the rubber. The best thing that we found to house the plaster model of my breast was an empty 2 gallon water container.
When you've found a suitable container or casing for your model, cut a hole in the bottom into which the plaster breast fits snuggly and then glue it in place from the outside with hot glue. (To ensure that the surface area of my mold would not be much larger than the surface area of the plaster breast, I added an extra wall to the inside of the container. While not necessary, I'd recommend it, though, frankly, it depends on the size of the model.)
Make very certain that the glue fills in all possible cracks from which the polyurethane rubber may leak. (To be on the safe side, you also may want to tape around the outside of the rig with duct tape.)
Step 4: Mix the Pourable Rubber
The PMC-744 polyurethane rubber is mixed in 2:1 ratio. In other words, there is twice as much of part B as there is part A. To be on the safe side, use all of both containers. This will keep you from having to really measure things out and do the math necessary to figure out the correct amount of each part (because the less time you have to spend working with and measuring out these chemicals, the better off you are).
What I did was to pour part B and thoroughly mix it in the container. Then I poured in part A and thoroughly mixed the both of them together. I continued mixing for a couple of minutes, but not for too long since the pot-life on PMC-744 is only 15 minutes.
Step 5: Pour the Rubber Mold
Slowly pour the rubber into the lowest possible point inside the mold and let it fill from the bottom up. Continue until the rubber is at least 1 inch higher than the plaster mold. Once done, give the whole rig a few good taps against the ground to force any surface bubbles upwards.
Place the mold somewhere outside where it is dry and not windy (or in a well-ventilated area) and let it sit for about 24 hours.
Step 6: Remove the Mold
After letting it sit overnight, remove the polyurethane rubber mold from the rig.
Trim away any extra rubber from the mold-making process.
Step 7: Bake the Mold (optional)
After demolding and cleaning up your breast mold, it would be a good idea to bake the mold in a toaster oven for 4 hours at 150 degrees. This will help increase the lifespan and durability of your mold.
Be sure not to use a toaster oven that you ever intend to use for cooking ever again. Do this outside or in a very well-ventilated area.
Step 8: Seal the Mold
Before you can pour silicone into the mold, you need to apply a mold release. The best mold release for pouring Dragon Skin silicone into PMC-744 polyurethane rubber is the Ease Release 800. Apply a thin coat, wait a few minutes, and then wipe up the excess. Wait a few more minutes, apply a second coat, and then, after a few minutes more, you should be ready to start with the silicone.
Step 9: Mix the Silicone
Dragon Skin silicone is mixed in a 50/50 ratio by weight or volume. This makes it easy to work with.
You probably won't need to use all of it, unless the breast you are working with is very large. Guesstimate about how much volume the breast will take up and then increase that number slightly.
Once you have an idea of the volume you are working with, divide that number in half to determine how much of part A and part B you will need. In other words, figure out the volume of the whole and parts A and B will be half of that amount.
Pour out part A and mix thoroughly.
Next, before pouring mix part B thoroughly. Once mixed, pour an equal amount of part B in with part A.
Mix parts A and B thoroughly for at least 3-5 minutes.
Step 10: Pour the Silicone Breast
Pour your silicone into the rubber mold so it fills the lowest possible point first, being sure that the rubber rises from the bottom as evenly as possible--like pouring cake batter into a bundt pan. Continue until the mold is evenly filled. Don't worry if a little runs off the sides since it can be trimmed later.
Give your mold a few good hits with something solid (like a paintbrush or screwdriver) to force air bubbles upwards and prevent them from ruining the surface.
Let it sit in a well-ventilated spot for 24 hours to fully harden.
Step 11: Demold the Silicone Breast
Now is the big moment!
Remove your silicone breast from the mold.
Step 12: Clean Up the Silicone Breast
Once it is done, you are going to want to trim off all extra silicone around the edge of the breast with a pair of scissors.