Gluing aluminium sleeve back into press fit BB

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Des49
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Joined: 2 Dec 2014, 11:45am

Gluing aluminium sleeve back into press fit BB

Postby Des49 » 15 Oct 2019, 5:02pm

Hi,
Just knocked out a press fit bottom bracket, unfortunately on the NDS the Al sleeve into which the bearing is pressed came out with the bearing!!

I have extracted the press fit from the sleeve by putting a cut into the plastic bearing. Everything cleans up ok and there doesn't appear to be any other damage. But I now need to glue the sleeve back into the frame before fitting a new BB.

Is Araldite ok for this? Being a 2 part epoxy it should be ok, or is something more specialised demanded. Whatever was used originally couldn't have been that strong! I need to do this repair without delay, I have Araldite to hand, also have some West System epoxy to hand but in large quantities and unopened so reluctant to break into this for a small job.

I was also wondering if it would be a good idea to fit the new BB at the same time and let the sleeve set with this in place, or to do one thing at a time. I am refitting a Hope bearing where the central sleeve screws in and holds the two bearing sections together. May avoid misalignment if the whole thing is done in one go, but the worry is completing it in time before the glue sets in 5 mins. Thinking about this a bit more, one thing at a time may be best and avoid making the situation worse.

Thanks.

Valbrona
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Re: Gluing aluminium sleeve back into press fit BB

Postby Valbrona » 15 Oct 2019, 5:21pm

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Last edited by Valbrona on 15 Oct 2019, 5:29pm, edited 3 times in total.
I should coco.

bikepacker
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Re: Gluing aluminium sleeve back into press fit BB

Postby bikepacker » 15 Oct 2019, 5:23pm

Argos at Bristol used red loctite when sleeving a BB on my super galaxy.
There is your way. There is my way. But there is no "the way".

Des49
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Joined: 2 Dec 2014, 11:45am

Re: Gluing aluminium sleeve back into press fit BB

Postby Des49 » 15 Oct 2019, 5:50pm

A pic to avoid any confusion.
BB sleeve.jpg

Des49
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Joined: 2 Dec 2014, 11:45am

Re: Gluing aluminium sleeve back into press fit BB

Postby Des49 » 15 Oct 2019, 5:57pm

bikepacker wrote:Argos at Bristol used red loctite when sleeving a BB on my super galaxy.


Hadn't thought of that, a strong thread locking compound may do the job. But this may not bond metal to carbon fibre.

In the future there will always be the need to replace the BB again, if the sleeve does move and is too well bonded in then damage to the carbon shell may be a risk. With the metal Hope bearing assembly I will grease the surfaces well before pressing in the new BB, then hopefully in future this will push out in preference to the sleeve.

alexnharvey
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Joined: 10 Jan 2014, 8:39am

Re: Gluing aluminium sleeve back into press fit BB

Postby alexnharvey » 15 Oct 2019, 6:00pm

Is it five minute araldite that you have?

How big is the gap between sleeve and frame? Do you need to find it in alignment whilst it's setting and how can you check it is ok?

Des49
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Joined: 2 Dec 2014, 11:45am

Re: Gluing aluminium sleeve back into press fit BB

Postby Des49 » 15 Oct 2019, 6:04pm

alexnharvey wrote:Is it five minute araldite that you have?

How big is the gap between sleeve and frame? Do you need to find it in alignment whilst it's setting and how can you check it is ok?


It is the 5min Araldite I have.

The gap is minimal, the sleeve just pushes in and out as long as it is perfectly square which hopefully means there is little chance of misalignment once it is pushed in fully.

tim-b
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Re: Gluing aluminium sleeve back into press fit BB

Postby tim-b » 16 Oct 2019, 5:39am

Hi
...but the worry is completing it in time before the glue sets in 5 mins

Consider a longer-setting epoxy? There's a thread here (link)
Regards
tim-b
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Des49
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Joined: 2 Dec 2014, 11:45am

Re: Gluing aluminium sleeve back into press fit BB

Postby Des49 » 16 Oct 2019, 7:29am

tim-b wrote:Hi
...but the worry is completing it in time before the glue sets in 5 mins

Consider a longer-setting epoxy? There's a thread here (link)
Regards
tim-b


Thanks for that link, which also led me into this viewtopic.php?f=5&t=82599&p=737995&hilit=bb+sleeve#p737995

A good deal of info on all that that I failed to find before I posted this thread.

I decided that the Araldite would be ok for my purposes, the surfaces are tight to each other and no filler was needed. I also decided that I would do one job at a time and not fit the whole BB and sleeve altogether. My initial thought was to do it all together to keep things in alignment. The Hope bearing press has a 41mm end, this was then used to keep the sleeve in alignment as I used it to clamp the repair up through the BB shell, not sure why I didn't think of this initially.

I cleaned up the surfaces to be glued with emery cloth, degreased with acetone, used car wax on all other surfaces near the repair to polish these up and prevent any stray glue adhering. Also waxed the end of the bearing press. Years ago I used to do some boat repairs using West or SP resins, by waxing screw or bolt threads these could then be removed ok before max cure was achieved.

This has been left clamped indoors overnight, so should be at close to max strength now. I will press in the new BB later.

I wonder if the sleeve was starting to debond from the carbon BB shell and hence came out with the bearing. When ridden there was only a slight occasional creak from this area which seemed to stop after removing and retightening the LH crank. But the LH bearing was running pretty rough and I decided replacement was a good idea, wasn't as simple as I thought!

The Hope BB design seems good with the actual bearings being replaceable and so should be no need to knock the whole assembly out, the locking sleeve between the halves also seems a good idea. I fitted one of these to someone else's bike maybe 3 yrs ago, still beautifully smooth, but they weigh less than 60kg and the bike is well looked after.