DavidF Posted 20 hours ago Posted 20 hours ago CMC is used to keep the solids in suspension in a black match slurry, not really as a binder. Typically, 4% dextrin and 1% CMC are used. It's very effective at keeping the slurry evenly mixed. PVB is used in making commercial waterproof quickmatch. It is very flexible and completely waterproof (for short times, at least). I've actually bent the bare match into a 'U' and stuck it in a can of water and lit one end. It burned all the way to the other end under the water. The stuff I got was very flat and made up of a gajillion very fine threads. The PVB we buy for pyro as a powder for binding will dry to a piece of tough, flexible plastic if it's dissolved in alcohol and the solution evaporated to dryness. The PVB in the quickmatch I mentioned seems to contain plasticizers. Folks refer to car windshields as a common use for PVB. It's the rubbery layer between two pieces of glass. That PVB has plasticizers too, just like the PVC a shower curtain or an air mattress is made from. The rubbery texture of the flat match led me to think it's got plasticizers in the PVB. A friend of mine had a bum leg and I brought a rocket to his birthday party. I wanted him to be able to light it from his chair. I took a couple of rolls of this waterproof quickmatch and ran it out to the launcher, spiking it to the ground every so often. It snapped, crackled and popped like English crackers all the way to the rocket. This short clip of mediocre video shows it: 1
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