Shelf life of RMS reloads

Back in 1997 I stocked up on E through G RMS reloads. I've been using
them on and off ever since, but I wondered if there is an official
expiration date for them. They have been stored in an air-conditioned
closet all these years, and they still seem to be working fine,
although they have gotten increasingly hard to ignite -- about the only
thing that seems to light them reliably now are Quickburst's Twiggy
igniters. I did notice that the propellant grains look like they are
sprinkled with talcum powder or maybe powdered sugar, but it doesn't
seem to have hurt their performance once ignited. Anyone know anything
about the shelf life of these progellant grains?
Reply to
Leslie Houk
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I have seen the same thing on some of my reloads. I use sandpaper to remove the oxidation from the grains and they seem to light faster. (220 grit on a dowel down the core of the grain for cored grains and 220 grit on a bit of balsa for c-slot grains)
I don't know of that is supported or even smart, but it works for me and I haven't lost a finger yet.
-Aaron
Reply to
Aaron
Solid rocket propellant is made out of pseudo stable, smelly polymers and other crap that are subject to varying degrees of aging, dependant on a very large number of factors. The short answer I guess is that if it blows up, it's expired.
Anthony J. Cesaroni President/CEO Cesaroni Technology/Cesaroni Aerospace
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(941) 360-3100 x101 Sarasota (905) 887-2370 x222 Toronto
Reply to
Anthony Cesaroni
Last year I flew a 13 year old I284 that had been burried in my stash. Those who remember the original reloads, this one had the two clear plastic delay spacer rings! No problems. I've also flown the D-G LMR reloads that were at least as old as the ones you have successfully.
If the bags are sealed, the propellant should hold up pretty well. Particularly WL tends to absorb moisture and swell once the bag is opened. If the grain won't fit in the liner tube, toss it. Otherwise, do as was already mentioned: rough it up a bit with some sandpaper to de-crud the surface.
Older grains can be difficult to ignite. The simple solution for the multi grain reloads is to swap the TOP grain (the one next to the delay where the ignitor goes) with a fresh one from a motor that uses the same type propellant. That's what I did with my 13 year old I284, and it was instant on at ignition.
Reply to
Bob Kaplow

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