Old motors, safe to use?

[OldManRocket]

I am just getting back into the hobby after a break of 15-20 years. Digging through all of my old rocket stuff today I found a bunch of reload kits (both AT and CTI) and single use motors stored in a non-climate controlled space. Where I live it does not get terribly cold or terribly hot but still, these motors have undergone some temperature and humidity cycling over the years. Most of them are still sealed in their plastic pouches. Do you suppose these would be safe to use so long as there are no obvious cracks in the propellant grains? I also found two reloads that have already been assembled into their respective AT cases, a K550 and a J350. Should I disassemble them, inspect them and put them back together? Would doing so be likely to cause problems with the delay train? Should I try to fly them at all? If no, any suggestions on how to dispose the the propellant grains?

I will mostly be building new rockets for this iteration of "BARhood" and would hate to blow them up! On the other hand, throwing away a thousand dollars or more worth of motors is gonna hurt. What would you do?

Thanks!

 

[djs]

AP doesn't really go bad, per se. What you should look for is grain swelling where the grains won't fit anymore into a liner, or oxidation. Oxidation occurs the most on white propellant (White thunder, white lightning). A quick sand with sandpaper will take care of this. If you didn't sand, it's not a big issue other than the motors might be hard to light.

For the ones that are assembled, take a look at the grains for the above issues. Then fly them!

Where are you located?

 

[OldManRocket]

Sounds good! What about black powder motors? I have a bunch of Estes motors and a few other brands. The E9's I'll probably just fly in sacrificial rockets but the rest should be okay?

 

[Zeus-cat]

Sounds good! What about black powder motors? I have a bunch of Estes motors and a few other brands. The E9's I'll probably just fly in sacrificial rockets but the rest should be okay?

They should be OK, but use the first few in sacrificial rockets just to be safe. I have used old black powder motors that someone gave me with no problems.

 

[UhClem]

The older Aerotech delay system had problems with motors being assembled for periods far short of years. The newer RDK+ doesn't have this problem because the o-rings are not compressed in the same way. If that K550 has the old style delay, I would be tempted to replace it completely.

Also, old APCP delays burn longer than new ones. I recently used a G64-4 that was in this age class which had a measured delay of more like seven seconds. So your best bet would be to use an altimeter to deploy and use the motor delay as a backup.

 

[OldManRocket]

So my best bet on the K550 and J350 that have been sitting in their respective cases for many years (both "old style") would be to remove the forward closure and replace with a plugged forward closure? I would definitely be using an altimeter for apogee deployment so I would just be losing the "motor backup" which would not be very reliable anyway after all this time. I'll probably just disassemble both motors and rebuild with fresh liners and o-rings using the plugged forward closure.

 

[dhbarr]

Plugged or new delay grains, yeah.

 

[pyrobob]

Yeah, I would replace the delay elements like Dave said, or go plugged with with altimeter deployment.

 

[markkoelsch]

So my best bet on the K550 and J350 that have been sitting in their respective cases for many years (both "old style") would be to remove the forward closure and replace with a plugged forward closure? I would definitely be using an altimeter for apogee deployment so I would just be losing the "motor backup" which would not be very reliable anyway after all this time. I'll probably just disassemble both motors and rebuild with fresh liners and o-rings using the plugged forward closure.

Just buy a new delay set or fly with an altimeter.


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[cosmojwm]

At a launch last summer a friend gave me a casing that had been loaded with a I161 for ten years.
I suck it in one of my rockets, it sputtered a little, but did a good job.

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[Handeman]

So my best bet on the K550 and J350 that have been sitting in their respective cases for many years (both "old style") would be to remove the forward closure and replace with a plugged forward closure? I would definitely be using an altimeter for apogee deployment so I would just be losing the "motor backup" which would not be very reliable anyway after all this time. I'll probably just disassemble both motors and rebuild with fresh liners and o-rings using the plugged forward closure.

I wouldn't even replace the forward closure, just don't put any powder in the ejection well.