Alloy BB shell come away from carbon frame – what adhesive?

Hi all.

At the weekend while tightening up my drive side b&b cup the whole alloy body started to turn in the frame.
I can’t get either bbc cup out so I guess the best bet is to drill a couple of holes and feed in some edhesive while turing the bb to twist the shell and distribute the adhesive. then I’ll probably add a couple of screws or bolts to fill the holes and stop any slippage. Good plan?

What adhesive to use ?

It’s my old single speed frame so not too bothered, but I’d like to get some more out of it if possible .

Thanks

Gorilla glue.

You need a high grade epoxy.
Araldite on steroids basically.

Can you suggest any ?

Gorilla glue.

That’s a brand not a glue, they make everything from wood glue to superglue (and all superglue is basically the same chemical so you’re paying for branding/thickener/the bottle).

Epoxy would be the correct glue, but I’d bet it’ll be far too thick to get into the gap between the BB and frame.

What you actually need by the sounds of it is this stuff,

Not sure why the packaging still says new, I’ve got some VERY old bottles in the shed, probably new relative to the old crusties on boats that use the stuff.

Epoxy would be the correct glue, but I’d bet it’ll be far too thick to get into the gap between the BB and frame.

It has worked on our Zesty when push fit BB insert came out. I will ask neighbour who we bought it off what epoxy brand he used.

Thinner the better I think. I know warm epoxy would be thinner but I’m not sure it’s going to be thin enough.

I’d go with epoxy. Probably standard araldite. If you can make sure all surfaces are clean, lightly abraded to give a key to aid adhesion and free of dust.

I’d be intrigued by a high grade epoxy, how much is chemistry and how much is marketing in terms of adhesion. My job involves a fair amount of work with epoxy/amine systems and in general they stick exceptionally well.

The forces involved in removing a stuck bb will probably overwhelm most glues so make sure you sue a good amount of grease/anti seize when you fit them.

If you thin the epoxy by warming it then reduce the amount of hardener to go with it.

As for brands, there may be a difference by I use poundstretcher epoxy in the double syringes on my boat and it’s never failed yet and no need to worry about keeping the caps clean, just use what you need and bin it at the end of the day.

Is it a pushfit? A hope bb screws together and has replacable bearings, so maybe you could try that if only one side is loose.

Jonba,

The bb cups are already in the frame and can’t be removed. The shell is also still in the frame and can’t be removed so I’m unable to clean, sand or prep the surfaces in any way.

It’s a case or Turing the bike up side down and drilling a hole/s under the BB and hoping for the best.

oooh, in that case maybe not epoxy as you’ll struggle to get one thin enough. You’d need to heat araldite to about 50C to get to flow into a narrow space and at that point you’d probably have a working life of seconds.

Maybe do a search of the Loctite range of products?

poundstretcher epoxy

chemistry cares not for branding. It is still probably BADGE and a polyamide.

on_and_on -1/4″ hole in bb shell and pump ‘glue’ in should work – you may want to turn and flip the frame to get gravity to help spread the ‘glue’.
Q: Wont the glue ruin the cups? Is it possible to use two bb tools to gain antagonistic purchase against ‘tother cup and remove at least one?

You can purchase very runny epoxies eg: IN2 from easy composites

– Funny enough the last CF frame I cut up looked liked ‘gorilla glue’ the wet and yellow expanding one had been used 🙂

Edit + in my case- leave to cure for a long time = hot green house for a week

My tiny brain is considering that my bb30 bbs stay in their frames without much hastle, so maybe these will be ok if I pop in some thin superglue and a couple of screws.
With the crank fitted the bearings spin but the shells stays still. How long this would work is the only question.
Any strong glue would make me feel a bit better 🙂

Sorry if this sounds dumb but can you get a lend of another bb wrench to hold the other cup? It is a hollowtech BB? (apologies if you’ve already tried this)

If one cup is held by a wrench, then, in theory, the other one should screw out which should give you better access.

Apologies if I’ve gotten the wrong end of the stick. Half asleep and skim reading…

Surely that’s a manufacturing defect and therefore warrantable?

Trailblazer.

It won’t work as I still won’t have access to the shell.
The carbon curves and overlaps the edge of the alloy shell making it pretty much sealed unless I drill holes (which I have already)

It’s an old frame so no warranty. I also stripped all the paint off and clearcoated it. I’m not sure they be too keen on talking it back 🙂

I’d be making a concerted effort to get the bb out first. At some points it will need changing and if it’s stuck now it might be stuck and glued later.
Plus if its out you’ll have access to the inside to drill and add expoxy

It’s a brand new bb so it will last a while. When it goes wonky the frame can be thrown away.
Also removing a BB cup won’t allow access to glue the shell. I can do that already though the hole I drilled in the carbon.
All I need is a compound, glue or adhesive to use which is thin enough. That’s all I need to know right now.

http://singletrackworld.com/forum/topic/carbon-frame-repair-advice-adhesive

Should be able to get the BB out with two BB tools, no? Turn them opposite directions? Then slide out the loose shell, and prepare and glue

I have successfully re-bonded the pedal inserts in RF Next carbon cranks using a low viscosity epoxy injected through holes drilled in the end of the cranks.

The stuff came from a boat chandlers. I can find the name if necessary.

Any details would be fantastic and greatly appreciated.

Try West System International
Their epoxy system was used to repair a Trek BB detailed here. It was different to yours because the shell had been removed, however they might advise you

Right – the stuff I used was West System 105 resin and 205 hardener (206 is slow to cure). Mini pack can be had for c.£20 from a good chandlers. I cleaned everything thoroughly with spray disc brake cleaner and drilled 1.5mm holes in the ends of the cranks and just into the inserts to provide a key.

I also bought a meat ‘marinade injector’ from an Ebay Hong Kong website for about £4 as it was the pretty much the same design as some woodworking glue syringes costing £££s and I thought I’d need a high pressure delivery.

In fact I think an ordinary plastic syringe would have been fine just to get the epoxy into the holes as it’s thin enough to penetrate with capillary action. I moved the cranks around to help the glue run – which may be tricky with a frame, and had masked off the threads.

I’ve had a few big pedal strikes since and they are still rock solid. I had nothing to lose by trying it and it seems to have worked – time will tell.

The west system resins look almost identical to Araldite on the MSDS. They’ve used IUPAC nomenclature to name the chemicals rather than their common names – probably to hide the fact there is no difference between their product and any other on the market.

West Systems, SP, or any other ‘boat building’ type resin is nothing like Araldite in actual use.

Boat building resins are low viscosity (think olive oil) and are a fraction of the cost of Araldite. Araldite is more like cold honey.

30ml of araldite = £8, 300ml of west epoxy = £18 (buy in bulk and it goes down to about half that price/vol.

But then again, you probably don’t need much.

http://www.ecfibreglasssupplies.co.uk/c-1087-resins.aspx

I would use 3M DP490
like this

https://www.cromwell.co.uk/MMM7057180G