Question for the techies...

[Sponge]

Hey,

I'm wondering what's the best way of going about 'breaking down' epoxy resin? I've glued one of my bearings into a lollipop holder to keep that snug for extra security, but I want to replace the bearings.

Will paint stripper work? I have a suspicion it could melt the epoxy resin?

Cheers!

[rob.northcott]

Acetone (commonly used as nail varnish remover or Hammerite thinner) is the best bet as a solvent - it will soften epoxy eventually if you can get it in there. Or heat it up if you can do that without ruining anything else.

Rob

[Nurse Ben]

Get it hot, this will loosen it up, maybe boiling water would be enough.

[tstessney]

Not too familiar with the lollipop set-up, but I've found the best tool for epoxy removal is a hammer. If the bearing slides inside the lollipop, I'd open up a bench vice to where it just catches the lip of the lollipop, place the set-up on top and gently tap the bearing out the bottom?

[harper]

What kind of epoxy is it? Do you have the brand name and can you get the spec sheet for it? That will tell you what your options are for attacking it with chemicals or heat.

If it's standard 5-minute epoxy it's not particularly strong, about 5000 psi, and the hammer technique might work fine to shatter the epoxy but won't help you get the bearing out of a lollipop holder. If the outer race is epoxied in you're screwed because the inner race is all you can smack. The bearing will probably break.

Good, two-part, 24 hour epoxies like Armstrong A-12 are closer to 50,000 psi. To begin to free it up you will need to heat it up...a lot. The epoxy eventually turns into dust I believe below the melting points of either aluminum or steel.

If you have successfully shattered or heated away the epoxy or destroyed its integrity in some other way, you still have to get the bearing out of the lollipop holder. I have done this before by milling (flat end mill about 3/16") a set of three to five holes through the lollipop holder over the outer bearing race and then using a drift punch through the holes to work the bearing out.

If you initially put the epoxy in there because the bearing was too loose, you may be able to use a large rod to hammer or press the bearing out by the inner race without destroying it. Use a cylindrical base to hammer or press against rather than the two-point contact of a pair of vice jaws.

This is NOT a cost effective way to do this. Buying a new lollipop bearing set will be cheaper and easier if it is at all possible.

[Sponge]

Thanks for all the replies so far.

To be more specific, the mix I got was a fairly cheap 'black and white' separated liquid mix in a double-syringe. It takes about a day or so to properly set. I got it from an electronics store.

I don't mind if I demolish the bearings as brand new ones are going in there.

These lollipops are *modified* Miyata ones with the outside face's hole bored out larger so that the inner race is revealed so I can easily start pounding on that... however, I'm trying to avoid maybe smashing the inner race itself out and then having an outer race and rest of bearing stuck inside the lollipop because of the epoxy resin.

Ideally I want to find something that'll 'melt' the solid layer of epoxy resin, kinda like how paint stripper makes paint melt and start bubbling off?

[rob.northcott]

If you don't care about the bearing then I'd try hitting it first to see if it comes out fairly easily (obviously support the holder like tstessney said). If it feels too stuck to get out without smashing the bearing (which would then be an even bigger PITA to get out like you mentioned) then try soaking it in Acetone and/or heating it up with a blow lamp, then hit it again. Are the lollipops steel or aluminium? Might have to be a bit more careful with heat and hitting if they're ally.

Rob

[Sponge]

The 'pops are fairly chunky steel. Very very hard, I can't drill through it at all with any of my tools unlike alu which is like cheese.

I'm not so bothered about how badly the bearings get destroyed but am more concerned about damaging/bending the pops. I would get new lollipops but I'd have to import them from Japan, and then need to find someone nice enough in the UK that'd bore out the centre hole.

Would be good if UDC could get in a Miyata popset for me? Assuming they still deal Miyata.