Introduction: Airsoft 40mm Special Effect Projectiles
P.M.O.G. Airsoft 40mm Projectile is a cheap, safe, and effective alternative to Nerf rockets used in Airsoft gameplay for taking out vehicles, bunkers, or, as indirect fire, personnel. One P.M.O.G. round costs around US 2 dollars in materials, and can be easily made with household or commercial products. P.M.O.G. is also safe. Using Lyon’s model for assessing injury potential of kinetic weapons, P.M.O.G. only makes a 9mm dent on ballistic clay, which is far below the lethal criterion of 44mm. When applying the model to Airsoft BBs and paintballs, the results are 13mm and 10 mm, respectively. So, P.M.O.G. is comparable to them. Using my own body for testing, I found that P.M.O.G. only caused some minor welts. I believe if gas pressure is kept below 500 psi in the grenade shell and 30 feet minimum engagement distance is observed, P.M.O.G. is safe to use in Airsoft gameplay.
Three are three types of P.M.O.G. rounds: chalk-filled, foam, and pyrotechnic and chalk-filled:
1. Chalk-filled round features a frangible blue foam tip with red chalk fillings, and a green rubber body. The tip is designed to break open upon contact and releases the chalk fillings, which simulates the explosion of a grenade. The chalk marking can easily be dust off unlike paint.
2. Foam round features a spongy yellow foam tip, and a green rubber body. The foam projectiles are designed to be reusable and can be used as practice rounds.
3. Pyro and chalk-filled round is just like the chalk-filled round except it has a snapper mounted on the tip. The snapper produces loud report upon impact with hard objects.
P.M.O.G. is shown to be able to hit a window-size target repeatedly at 60 feet provided there is consistent amount of gas in the grenade shell. But hitting an 100+ feet target is also possible. P.M.O.G. can also fit a great variety of grenade shells and launchers, such as G&P and S-Thunder shells, M203, XM203, EGLM, M72 LAW, and RPG7.
There are three major steps in making P.M.O.G. Airsoft 40mm projectiles: molding, casting, and assembling. The initial material costs will be around US$ 150, but the material cost for each round is about US$2 once you set everything up. As for labor time, one P.M.O.G. projectile takes about 15 minutes to make if you make a set of six in one session.
See also three attached supporting documents:
1. P.M.O.G. Making Tool and Material List (27 rounds)
2. P.M.O.G. Making Tool and Material List (252 rounds)
3. P.M.O.G. Manual V2.0
Step 1: Molding
Here are the tools and materials needed for making molds:
1. 2 plastic cups
2. Alumilite’s High Strength 3 mold making rubber 5 lb kit
3. A stir stick
4. A heat glue gun and heat glue sticks
5. A Steel ruler
6. 2-in PVC pipes in the length of 1.5 in, 2 in, and 3 in
7. A shortened rubber PVC pipe coupling
8. Alumilite’s Rubber-to-rubber mold release
9. A Q-tip
10. A digital kitchen scale
11. A corrugated plastic sheet
12. Alumilite’s synthetic modeling clay
13. Disposable gloves
Last, but not least, you’ll need to order the P.M.O.G. 3D-printed models from Shapeways. The order links are provided in the video description below. The reason for not using hobby 3D printers is that Shapeways can print models with very smooth surface, which greatly improves the quality of molding and casting as well. Just make sure you choose “white strong and flexible polished” as printing materials.
The first step is to apply a thin layer of Alumilite’s Rubber-to-rubber mold release on the inside of the PVC pipes and all the surfaces of the P.M.O.G 3D-printed models except where you’ll be gluing to the corrugated plastic sheet. Make sure you put some mold release in the crevasses between the fins of the P.M.O.G. body. And don’t forget to put some mold release in the hollow part of the P.M.O.G. body and tip. Next, glue a half-inch hot glue stick on top of the P.M.O.G. tip, and then glue the assembly on to a corrugated plastic sheet. Hold it steady for 10 seconds. Check and see if the bottom of the P.M.O.G. tip is level with the ground. If not, take the P.M.O.G. tip off and repeat the previous step. Glue the P.M.O.G. body on a corrugated plastic sheet. Hold it steady for 10 seconds. Put the 3-in long 2-in PVC pipe on the corrugated plastic sheet with the P.M.O.G. tip in the middle. Assemble the 1.5-in and 2-in long 2-in PVC pipes together with the rubber coupling, and then place it on the corrugated plastic sheet with the P.M.O.G. body in the middle. Next, put the Alumilite’s synthetic modeling clay around the base of the PVC pipes, and use your finger to seal the space between the base of the PVC pipes and the corrugated plastic sheet as much as you can. Afterward, measure 170 g of Alumilite’s High Strength 3 mold making rubber and 17 g of catalyst. Pour the catalyst into the mold making rubber, and use a stir stick to mix them slowly until the mixture is evenly pink. Make sure you use the stir stick to scrap the side and bottom of the cup while mixing as well. When the mold making rubber mixture is evenly pink, pour it into the PVC pipe holding the P.M.O.G. body slowly. Make sure you let the mold making rubber flow by itself to all parts within the PVC pipe. Do not attempt to distribute the mold making rubber, as it will create air bubble in the molds. Also, make sure the mold making rubber submerge the P.M.O.G. body by at least an inch. If it falls short, you will have to make extra mold making rubber mixture to reach the goal. Measure 110 g of Alumilite’s High Strength 3 mold making rubber and 11 g of catalyst, mix them and pour the mixture into the PVC pipe holding the P.M.O.G. tip according to the previous instructions. Allow the mold making rubber to cure for at least 18 hours. Keep in mind that cold weather may delay the curing time. You could test if the mold is cured or not by poking it with a stick. If it feels like poking a rubber, it is probably ready to demold. First, yank the PVC pipes away from the corrugated plastic sheet. Sometimes, the PVC pipe will come off and leave the mold in place, which makes things easier. If the mold remains inside the PVC pipe, insert a steel ruler into the space between the mold and the PVC pipe and push it to the other end. Keep doing so until there’s enough mold coming out of the PVC pipe for you to grab on. At that moment, grab onto the mold and wiggle it off the PVC pipe. With the P.M.O.G. body mold, it is more difficult to remove the mold from a single PVC pipe hence the need of the two-piece PVC pipe assembly. Remove the PVC pipes, and wiggle the P.M.O.G. body mold from the rubber PVC pipe coupling. Use a knife to remove the extra rubber from the top and bottom of the mold. Make a bisecting cut from the top to half an inch above the bottom of the mold. Peel the mold away from the 3D-printed model carefully. There might be some rubber connecting near the fin area, so peel carefully and use a knife to part the connecting rubber. Once the mold opens up like flower petals, grab onto the “petals” and the 3D-printed model and wiggle them apart. Use the same method to remove the P.M.O.G. tip mold. To make the mold of the practice round tip, an additional step is needed. Peel the “petals” of the mold back, and measure and mark 3/8th of an inch above the base of the “dome”. Cut off the rubber above the marking.
Step 2: Casting
Here are the tools and materials needed for casting:
1. Alumilite’s Super Foam 320 16 oz kit for casting chalk-filled tip. You’d also need three 1-oz measurement cups. One for the A compound, one for the B compound, and one for mixing them together. A stir stick is needed as well.
2. Alumilite’s Flex Foam 32 oz kit for casting practice round tip. You’d need three 1-oz measurement cups and a stir stick as well.
3. Alumilite’s Flex 80 16 lb kit for casting projectile body. The reason for getting such a large kit is due to greater material need for casting projectile body. The 16lb kit also requires two additional 1-oz pump dispensers, but I’d order three in case the pump dispensers get clogged. You’d also need two 1-oz measurement cups, a large plastic cup, and a stir stick.
4. Mold for chalk-filled tip and two 2-in PVC pipes in the length of 2 inches.
5. Mold for practice round tip and two 2-in PVC pipes in the length of 2 inches
6. Mold for projectile body and two rubber bands
7. Alumilite’s UMR mold release
8. Alumilite’s dye in red, green, fluorescent yellow, and blue
9. Four 1 c.c. syringes for dispensing dye
You’d also need a microwave. It is for heating up the projectile body mold to reduce air bubbles during casting. Alumilite claimed their molding materials are safe for heating. But if you are worried, you could use an old microwave instead of the one in your kitchen.
Also, the 1-oz measurement cups can be reused if you wipe them clean with paper towels after the end of the casting session. This will save you some money in the long run.
Notice that I only have one set of molds in the video, but you could have multiple sets for casting in one session. In fact, it will be more efficient since it takes almost a day for the casting materials to cure. I recommend that you make a set of molds each day during a week, and begin casting in the following weeks.
To begin casting, first you’d need to spray a generous amount of UMR mold release inside the molds. Make sure you spray some in the fin area of the projectile body molds, so that when the casting materials cure, they won’t stick to the molds and potentially damage it.
For casting projectile bodies, first you’d have to nuke the molds for 1 min and 30 seconds. You could heat multiple molds at the same time. I found out that I could heat up to 3 molds at a time before they cool off near the end of the casting session. After heating, keep the mold closed with one rubber band near the top and one at the middle. Next, measure 15 c.c. of Alumilite’s Flex 80 Compound A and 15 c.c of Compound B, and pour them into a large plastic cup. Add 0.05 c.c. of green dye into the mixture. Stir the mixture slowly to prevent creating air bubbles for about 20 seconds. Afterward, pour the mixture into the mold slowly and at a height of about 10 inches. This will also help reducing the amount of air bubbles created.
For casting practice round tip, do not heat the molds. Measure 6 c.c. of Alumilite’s Flex Foam Compound A and 6 c.c. of Compound B, and pour them into a 1-oz measurement cup. Add 0.2 c.c. of fluorescent yellow dye into the mixture. Stir the mixture for about 10 seconds, and pour the mixture into the mold. Immediately, keep the mold closed by sandwiching it with two PVC pipes.
For casting chalk-filled tip, do not heat the molds. Measure 3 c.c of Alumilite’s Super Foam 320 Compound A and 3 c.c. of Compound B, and pour them into 1-oz measurement cup. Add 0.05 c.c. of red or blue dye into the mixture. Stir the mixture for about 10 seconds, and pour the mixture into the mold. Immediately, keep the mold closed by sandwiching it with two PVC pipes.
The Flex 80 takes about 18 hours to cure, and the Flex and Super Foam 320 about a couple of hours. I’d just let them stand for 24 hours.
The casted products need some finishing touch when they come out of the molds. You’d need a flush cutter, and a ½-in hole punch or a knife. To take the casted projectile body out, you’d need to remove the rubber bands, and carefully peel the “petals” of the mold away. When the “petals” come off, you could fold them back, grab the casted projectile body, and wiggle it off the mold. To take the casted chalk-filled tip out, you’d need to remove the PVC pipes, and carefully peel the “petals” of the mold away. When the “petals” come off, you could fold them back, grab the base of the casted chalk-filled tip, and wiggle it off the mold. The casted tip is very fragile, so try to be gentle. To take the casted practice round tip out, just follow the previous instructions.
When all the casted products come out, use the flush cutter to trim off excessive materials. For the pyro / chalk-filled tip, use a hole punch or a knife to cut a hole in the middle of the tip.
Step 3: Assembling
Here are the tools and materials needed for assembling:
1. Hot glue sticks
2. Hot glue gun
3. Bottle of chalk and flour mixture
4. 1-oz measurement cup
5. P.M.O.G. projectile bodies and tips
6. Super glue
7. Adult snappers
The chalk mixture is made of 30 percent chalk and 70 percent flour. Adding flour not only reduces cost, but also makes it easier to clean up marking.
For assembling the practice round, apply a layer of super glue around the neck and the top of the projectile body, and attach the practice round tip on the projectile body. Use a rubber band to keep the tip firmly on the projectile body, and remove the rubber band after a few minutes.
For assembling the pyro / chalk-filled round, first glue three adult snappers together. Put the tip on the projectile body, and thread the adult snappers through the hole on the tip until they touch the top of the projectile body. Use hot glue to seal any gap between the snappers and the tip. Allow the glue to set, and take the tip off. Place the tip upside down in the 1-oz measurement cup, and fill the tip with the chalk mixture to about half an inch from the top. Apply a thin layer of hot glue inside the crevasse around the neck of the projectile body, as well as around the lip of the tip. Immediately, attach the tip to the projectile body, and hold them together for about 10 seconds. Test the strength of the bond. If they come apart too easily, peel the hot glue off and try again. For assembling the chalk-filled round, simply follow the previous instructions, and skip the part about adult snappers.
Step 4: Note
Here is the playlist of P.M.O.G. Projectiles including development, safety tests, and reviews: PMOG Playlist
Be advised, though. As you make your own P.M.O.G. Projectiles, they might NOT be accepted by field owners or event producers due to liability. I have done quite a lot of safety testing myself and I think they are safe to use with 30 ft MED. But you shall not hold me responsible in court since I do NOT make or sell them. Safety test videos:
1. Safety test 1: https://youtu.be/FocXStzGLA4
2. Safety test 2:https://youtu.be/SNlobal6bqU
3. Vehicle safety: https://youtu.be/5db0Begh-RQ
Owner of P.M.O.G. Armory