Silicone Mask

thingiverse

Materials: Smooth-on 940 food grade silicone rubber Silc Pig Colorant (without colorant, the silicone is pink) Silicone release spray Elastic bands Filter material Equipment: Reusable caulk tube: 'Tube A New' on Amazon for easy cleaning Caulk gun Vacuum chamber Pressure pot Reverse pliers Hot glue gun Angle wire cutter Scalpel This is a 3-part mold for making a silicone mask. It holds together with 1/4 inch bolts. Some hot glue to cover cracks between parts of the mold will reduce leakage of silicone. This mold makes a Large size mask. To make a smaller size, scale down the mold. I guess 96% for Medium and 90% for Small. The mask and two inserts fresh out of the mold without flash trimmed off weigh about 6 oz. Mix a little more than that at the start, maybe 7 or 8 oz. It's better to have too much silicone than not enough. Any extra can be poured into a plastic lid for a coaster. Smooth down parts of the mold if making a finished product. This will make a better-looking part easier to clean. If all parts are the same color, don't worry about it. Otherwise, go from lightest colors to darkest or use Smooth-on XTC-3D or lacquer. Degass silicone in a vacuum chamber and pour into an empty reusable caulking tube. Use a caulk gun to apply slow steady pressure to push silicone through the mold. The mold is oriented so that the mask is upside down. Slowly inject silicone into the mold through the hole in back near the nose piece, holding the mold at a 45-degree angle to minimize bubbles. The silicone will come out the vent at the top when the mold is full. The wider holes around the vents are reservoirs for extra silicone. When the mold is full, plug the inlet with a 1/4 bolt wrapped in paper towel. Place molds in a pressure chamber to minimize bubbles. I use a converted 5-gal spray paint pressure pot. In a heated pressure pot, silicone takes about 2 hours to cure. If the pressure pot is not heated, leave it overnight. Open the mold slowly and carefully with reverse pliers, applying just enough pressure for the silicone to pull away from the parts of the mold. Work your way around the mold to loosen the silicone's grip. Use angled clippers and a scalpel to cut away any extra flash. I recommend using 2 layers of melt-blown polypropylene as filter material cut into 3.5-inch squares, with a water-resistant layer on the outside to repel water droplets in the air. The mask is held in place with two elastic bands, each 24 inches long, with a slip knot on one side for easy adjustment.