Removing A Retainer

[Normzilla]

So I started a build prematurely without checking if angles were truly flat and even. Glued in, using JB Weld, an Aeropack tail cone to a MMT that's a tad skewed. It's a 54mm and I noticed when I use a 38mm reducer that the motor sticking out the fwd end is bias to a side and not centered.

Is this a problem for the reduced 38mm (stupid question?)? Would it be a problem for a 54mm?

Is there any way you all would recommend I remove the retainer (epoxy is set and like a rock) if needed?

Thanks all.

Nate

 

[Banzai88]

Heat. Some use a torch, some a hot plate, some a heat gun. Either way, plenty of heat will break down the glue and allow you to take it off. How much heat it'll take, what you use, and how you apply it will determine if the underlying structure if reusable.

Use oven mits, it'll be hot.

Off center thrust would not be advisable. Unpredictable at best, unsafe at worst.

 

[manixFan]

How much of an angle? If it's not much I would not worry about it. I was given a bunch of rockets to salvage by a club member who was getting out of the hobby. Many had Aeropack or Slimline retainers on, most held on with JB weld. It is a challenge to get the retainer off without damaging the surrounding areas. I have a very powerful heat gun that will eventually heat the JB weld enough to soften it but in most cases the the surrounding epoxy was also softened which is obviously not a good thing. And once free it's a bear to clean the old JB weld off the retainer.

Regular epoxy is much easier to deal with, I've recovered a lot of G10 fins by heating the epoxy with the heat gun and just scraping it off. But with JB weld, it's a lot more work.

Good luck,


Tony

 

[mpitfield]

I have tried to remove 3 retainers now. A GLR 3" to 54mm tailcone, a GLR 29mm Slimline and an Aeropack 38mm, all glued on with JB Weld and with zero success. Ultimately I had to cut all three off, which is what I will do next time without even trying the heat and remove. Admittedly I stopped the process and maybe prematurely, due to concerns with the heat of the retainer and the distinct smell of burning fiberglass.

 

[Normzilla]

I have tried to remove 3 retainers now. A GLR 3" to 54mm tailcone, a GLR 29mm Slimline and an Aeropack 38mm, all glued on with JB Weld and with zero success. Ultimately I had to cut all three off, which is what I will do next time without even trying the heat and remove. Admittedly I stopped the process and maybe prematurely, due to concerns with the heat of the retainer and the distinct smell of burning fiberglass.

How did you take the lip off from the retainer that was attached to the mmt? Dremel and sanding stone?

 

[blackjack2564]

Use hair dryer set on high if you don't have a propane torch.
Focus heat on inside of retainer metal to glass area while rotating.
Then on outside metal flange.
Then I just stick screwdriver under metal lip/tube joint and "pop" the retainer off.
The heat soaks into glue, under metal ,a few seconds after direct application.

It's a technique learned. I can pop off a retainer in under a minute and sorry to say.....had to remove many. LOl
wear a glove on one hand....it gets very hot. then use wire brush to remove glue from retainer while keeping it warm.
no need to get every speck off

 

[mpitfield]

Dremel using a cutting wheel and the round headed bit that can eat into the aluminum, then needle nose pliers. Once you get it cut you simply grab with the pliers and twist and it peels off easily, then its a simple clean up. One thing on that round headed chewy bit, it can get away on you easily so a firm grip on the dremel with steady hands is needed.

 

[Normzilla]

Use hair dryer set on high if you don't have a propane torch.
Focus heat on inside of retainer metal to glass area while rotating.
Then on outside metal flange.
Then I just stick screwdriver under metal lip/tube joint and "pop" the retainer off.
The heat soaks into metal a few seconds after direct application.

It's a technique learned. I can pop off a retainer in under a minute and sorry to say.....had to remove many. LOl
wear a glove on one hand....it gets very hot. then use wire brush to remove glue from retainer while keeping it warm.
no need to get every speck off

Thx BJ.

Will do

 

[Zeus-cat]

A heat gun would be a better choice than a hair dryer as they got noticeably hotter. Ask around to see if you can find one. Harbor Freight has a cheap one for $14.99 It would probably last long enough to get your retainer off.

 

[Chris_H]

With a heat gun, or a torch, this is an easy task. Heat it up pretty hot but not so you are burning the fiberglass tubing, use something metal that will 'catch' an edge on the retainer, and tap it with a hammer. Should be a piece of cake. I have done this a couple of times.

 

[Chris_H]

I think I used a torch. Either one will work. If you use the torch, just keep it moving. The torch is more likely to concentrate the heat in the metal, if you are careful, as it is hotter, thus, quicker.

 

[SDramstad]

Could you heat it then tap it into position without removing it?

 

[Chris_H]

The epoxy is compromised at that point. Best to remove it, sand the tube enough to clean it, scrape the interior of the retainer a little, and re-glue it.

 

[Banzai88]

Could you heat it then tap it into position without removing it?

Once the glue is compromised by heat, it's likely not going to have nearly it's original, or enough, strength. Why play 'bet your life' on a hot falling metal object? Just pull it off, clean it up, and use new glue.

 

[Normzilla]

Ok. Got it off using a heat gun.

I used a shaped, really thin, wedge to slide between the retainer and the mmt and worked it around, scraping the epoxy out.

Slowly but surely, after heating and scraping a few times, it came off with some effort.

Cleaned the mmt off of any old epoxy, and I used the other side, which was the side I had trued originally, reepoxied the cleaned retainer and the mmt and reattached.

Looks straight now.

Thanks all for the guidance.

Nate.

 

[farsidius]

Glad the heat gun worked for you. That's what I've used to remove a few retainers from unrepairable rockets. Just apply heat for a minute then pry or pull off. Also, for anyone looking to get a heat gun, the Harbor Freight one is frequently available for just $8.99 with a coupon. Just look for one of their ads in your mail flier or favorite magazine - there's almost always one there.