Freehand Silicone Dome Darts

These domes are still molded with a dome mold. However, unlike the 2-piece system which requires the tooling be rather precise AND the silicone to cure anaerobically, these can be made with cheap ordinary hardware store silicone and a crude dome mold. The downside is that since the domes are centered manually, you need skill and patience to make them well.

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The point of these darts is to provide greater safety than darts using hard materials (ie slugs, hot glue domes), AND to provide drastically drastically reduced aerodynamic drag. Although the rubber domes are more painful than a felt padded dart for equal kinetic energies, a lower powered blaster can be made to achieve the same effective range with much less kinetic energy than would be required of a slug dart.

Typical weight for this type of dart is 1.2g

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You need some blanks with holes in them to form the stem. The hole size isn't critical, but I'd recommend 1/4". I used 5/16" holes because the blanks were pre-drilled a few months ago for use with VANS. The tips of them are faded from sitting on my porch in the sun for 3 months.

Squirt some silicone into the domes on a dome-mold. Make sure the domes are completely filled to avoid bubbles.

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You can make dome-shaped depressions with a bit called a ball end mill (Such as mcmaster 8900A32 for $27.31). Getting them to a consistent depth (.188" for me) will be tricky depending on what tools you are using. 

I hope to get some more molds CNCd and distributed for people (including myself), I'm waiting on a quote as of 8-27-12.

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Press down on the mold with something flat, and carefully slide it away. Alternately, you can slowly and carefully wipe with something flat. A flat, smooth bottom to the domes is ideal, but don't despair if they are a little bit rough, as the placement process tends to fill in minor irregularities. Don't take more than 15 minutes total for this step, or you may have problems with the silicone forming a skin. Then wait for them to cure at least 36 hours.

Demold the domes. Here, I didn't do a good enough job wiping off the excess silicone, which made them easier to demold, but added a descrting step to get clean domes off of the sheet. 

Squirt some silicone in the holes. Leave them SLIGHTLY overfilled.

Put the domes on the filled holes. Press down on them a bit to get good contact between the dome and uncured silicone, but ideally not so much that silicone starts oozing out the sides.

Now you need to wait for them to cure. They can be handled after 24 hours, but I dont recommend shooting them for at least 48. Once that's done, they're ready to shoot, but I recommend some quality control. 

Some of my domes were significantly off-center:

Some had excess goo oozing out of the sides:

Some were just right:

I'd guess about 1/4 off center, 1/4 too gooey, 1/2 just right (I didn't count). Most of the "too gooey" could be recovered into the "just right" category with some descrting, although some had too much scrt or were also off center. The off center darts are probably fireable, but not very accurate.

It is well known that these domes don't fire reliably out of a conventional wye hopper. Aside from the difficult to make alternative hopper designs, there are a couple ways to make them hopper. One is to spray cooking oil on the inside of your wye, which will get it sticky and nasty over time.

Another way, which I just discovered/tested, is to keep all your darts in a bag full of cornstarch. (Pictured darts are actually the blue-silicone 2-part mold darts, as I wanted to give these darts more cure time before firing them).  

This is less gross, but probably equally messy. You really need to plan on one side of your pants being coated in cornstarch from wiping your hands, and the rest of your clothes to get a few splotches as well. The darts will fire through a hopper several times without being recoated in the cornstarch bag in dry conditions. I assume that rain will completely ruin this.  Also, it's worth noting that although these will fire every time, they occasionally do the streamline swirl-out when fired from powerful hoppered blasters.  The effect seems to be isolated in hoppers (like the conventional wye hopper) that force the dart to briefly bend while feeding.  Lower powered blasters, such as HAMPs, don't appear to have this problem, so the darts can be expected to fly straight every time.

Also, running around with a bag of white powder strapped to your hip will make people think that you're carrying cocaine. So you should label your bag of cornstarched darts to avoid confusion.

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