Aero Pack Retainer Question

I was just looking at the Aero Pack Retainer (54mm RA p) for the build I'm working on, with my first 54 MMT rocket. When I unscrewed the retainer cap there was a silver ring inside that came out. I have never seen this in my 29 and 38 mm retainers. Can someone tell me what this is for? The retainer is a little loose on the fiberglass MMT, is it a shim to take up some of the looseness?

My 54mm retainer didn't have the silver ring. I've used several Aero Pack retainers from 29mm to 75mm and have never seen that before.

The silver ring is to be used on thin wall fiberglass. Wildman started shipping those when he first started selling thin wall glass kits as the Aeropack retainers were too loose.

smugglervt said:

I was just looking at the Aero Pack Retainer (54mm RA p) for the build I'm working on, with my first 54 MMT rocket. When I unscrewed the retainer cap there was a silver ring inside that came out. I have never seen this in my 29 and 38 mm retainers. Can someone tell me what this is for? The retainer is a little loose on the fiberglass MMT, is it a shim to take up some of the looseness?

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You have a retainer for the standard wall fiberglass motor tube. If you have a thin wall motor tube, the silver ring makes up the difference.

So does the silver ring get epoxied to the mmt and then the retainer epoxied over that?

I think Wildman said to epoxy the ring to the MMT & then the retainer to the ring - at least that's how I did it!

for thinwall fg motor mounts, yes the silver ring gets epoxied onto the motor mount tube 1st(and whatever you do keep the outside surface clean, there is very little clearance for the aero pack retainer*). this is to allow you to get it into the proper position. then epoxy the retainer onto the mount.
Rex
*mine was such a tight fit it was tempting to leave out the epoxy for the retainer...I used a softface hammer to get the retainer on .

Thanks everyone, that's what I thought it was for but wanted to make sure since it was the first I'd seen this setup.

Thanks again

just thinking out loud here..

What if you drilled a few holes around the shim. Then, applied epoxy to the MMT and the shim, slip the shim in place. Then, without missing a beat, apply more epoxy to the outside of the shim and the inside of the retainer, then slap the retainer in place. Essentially gluing the shim & retainer in place at the same time. The thought is that with the holes in the shim, you maintain a bond between the retainer and the MMT, thru the holes in the shim.. You're not relying on the layers: FG-glue-AL-glue-Retainer... Just 4 or 6 holes, maybe 8 equally spaced about the shim..

well the 'shim' does have grooves in it so the epoxy can 'key' into both the shim and the retainer.
Rex

Paul, that sounds like a good idea but the ring is such a tight fit on the retainer I'm afraid I won't be able to keep it in place when sliding the retainer over it. Like Rex says there are grooves on the ring. I think it will be fine.

OK, was not aware of that! Thought it was a smooth ring..

yes, that will do the trick!