Salvaging Motor Retainers

As like some of you I'm some what partial to Aeropack Motor Retainers. I know they are expensive and more than most retainers, but they work really well.

My question is what do you do when your rocket for whatever unfortunate reason becomes destroyed and you are unable to rebuild it. What would be the best way to salvage the retainer?

I was thinking that maybe using a Dremel tool and some of the unique attachments to some how remove it and clean it up or would it be more practical just to buy the collar portion of the retainer? Most of the rockets I've been building I have Aeropack retainers, so that's why I posted this thread.

I have cut and removed a lot of retainers lately.

I have just used a razor and cut around the retainer till it is just a stub sticking out then I just peel out the tube and may soak the retainer over night in your favorite solvent and that seams to help get the epoxy off.

Fiberglass MMTs you are on your own.

Would you recommend acetone for soaking the retainer in?

AfterBurners said:

Woulds you recommend acetone for soaking the retainer in?

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Acetone would be good, its pretty powerful compared to stuff like paint thinner, and is pretty much required if you are working with something bonded with epoxy resin. Even then it is nearly impossible to dissolve cured epoxy. Just make sure you cover the soaking container so the acetone doesn't evaporate. Like you said, you can dremel the remaining body tube out of the retainer. It wouldn't have the grooves like when it was new but it would still be a rough surface to bond to when you put it on your next rocket. This is why I prefer the retainers with the hex cap screws instead of the glue on ones, but that only applies to the larger ones.

I don't think acetone is much of a solvent for cured epoxy. Most epoxy solvents (if not all) are very nasty. Google can locate them for you.

I'd try the mechanical method. Leave some tube sticking out. Split the tube with a saw, and carefully using a dremel or similar, split along the inside and down to the threads. Grab with vice grips and try peeling it off around the inside. Epoxy won't have stuck super solidly to the anodized threads so this might work.

Heating also softens epoxy, but it softens the aluminum as well. I'd recommend avoiding that method.

Gerald

A great solvent for epoxy is methylene chloride found in many paint strippers. I used that to clean up a fouled attempt at making fin stock when I had my granite slabs poorly waxed.
-Ken

I asked this very question a while back https://www.rocketryforum.com/showthread.php?44467-How-to-undo-a-JB-Weld-bond

There is a much faster way to remove retainer. Take a hand held propane tourch go around the retainer 5-6 times with the flame and the retainer will pull right off. Than take a dremal with a wire brush and clean out expoy from the retainer. Rocket with fiberglass tubes I do it in the basement. Paper tube rockets I do it outside just in case the paper tube starts on fire. Its fast, easy, and clean to do.
gp

crossfire said:

There is a much faster way to remove retainer. Take a hand held propane tourch go around the retainer 5-6 times with the flame and retainer will pull right off. Than take a dremal with a wire brush and clean out expoy form the retainer. Rocket with fiberglass tubes I do it in the basement. Paper tube rockets I do it outside just in case the paper tube starts on fire. Its fast, easy, and clean to do.
gp

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Yep.....way I've been doing it for years. Never scorched a tube yet.

Sounds like the torch method wins! I wondered about that. Faster, less nasty chemical. Good to know!
Ken

You only need to get the aluminum up around 400 degrees or so to remove the temper, from T6 down to T0. It will recover to T1 in about three days but that's all you get back. For long term heating, some property changes are detectable with as low a temperature as 200 to 250 degrees. Many epoxy types will require greater temperature to get them to decompose. That's why I recommend against the torch or heat gun method with aluminum that is structural. Particularly not a torch, as it provides considerable localized heating.

Gerald

Ive removed aeropack retainers from fiberglass and carbon. I use reinforced cut off wheel on a dremel and cut right next to the aeropack then go round and round with the cutoff wheel inside til i hit metal. Test fit and if it fits epoxy it. Works like a charm.