Ciera

My friend has a new carbon fiber frame with a threaded metal insert in the bottom of the bottom bracket shell. The insert is there to provide a means to attach a cover plate with a short bolt. The cover provides access to shift cables/wires.

The problem is that the insert was not glued in correctly. The insert protrudes too far into the bottom bracket shell and prevents the installation of a Wheels Mfg threaded 386EVO bottom bracket. I have the same frame and the insert is flush with the bottom bracket shell on the inside and outside.

How can he remove the insert? Is it OK to heat the insert with a soldering iron to loosen the glue/epoxy? Will this damage the carbon fiber? What commonly available glue/epoxy should he use to reattach the insert?

By the way, I assume the insert is glued in. Perhaps I am wrong?

The frame is a BH Quartz, made in Taiwan.

CliffordK

Is the is a new frame? What does the manufacturer say? Warranty? It doesn't appear to be a cheap bike/frame.

Upload some photos of the problem pieces. Go to the advanced editor and click on the paper clip icon to attach JPG images (around 100 kb).

Ciera

This is a new, old stock good quality frame and was an ebay buy from a reputable reseller. It may have a warranty.

That said, an hour after I posted this thread I found out my impetuous friend ground down the insert at the inside of the bottom bracket shell with a Dremel. The Wheels Mfg bottom bracket now slides in easily. I hope there is enough thread left for the cover bolt to latch onto. It is not a bolt that gets much load.

So, please ignore the thread or if someone knows how to remove a metal insert like this one, then the answer may help someone in the future.

My thought was to screw in a bolt, apply heat to the bolt while pulling on it so as to remove the insert as soon as the heat loosens the glue. I read that you can safely get up to 275-300 degrees F before you start to see any damage to a carbon fiber frame.

CliffordK

I believe dropouts are removed with heat, so it is probably a similar idea. Just get the heat source as hot as possible, but also localized to the part being worked on.

Mopzilla

a soldering iron won't be nearly enough heat. you'll need a propane torch at the very minimum, or better a map torch if you don't want to wait a while. As I understand, CF is very heat resistant and you can probably break down the glue by heating it to around 5-600*F.

unterhausen

this stands a good chance to become the thread containing the most bad and/or dangerous ideas ever posted on bikeforums. High stress area, cleanse with fire, what could go wrong? I think the dremel idea was probably the best one under the circumstances.

Andrew R Stewart 

I agree with Eric. Open flame around cosmetic paint and heat activated glues... I don't think so. Or not without a lot of careful shielding to prevent the flame from touching the carbon/epoxy.


BTW i'll take issue with the OP's claim that the cover bolt's threaded insert was incorrectly done. Was the OEM crankset/Bb able to be fitted? If so then I would then ask if the frame was represented in being able to have non standard/OEM parts installed? I very much doubt that and more likely there is some fine print in the warranty about modifying or changing the bike voiding warranties. Any idea to what crankset/Bb that did come stock in this frame when sold as a complete production stock bike?


Now I'm not saying that a bike should only be able to support the OEM spec and non other. Just that if I were the manufacturer I would strongly consider non OEM/alternative parts to be out warranty coverage. As a rider this sucks. As a hobby frame builder this situation is one I strive to avoid. Making my bikes as future compatible as I can and still maintain the basic design goals is a good thing. Andy.

Ciera

Chances are the OEM specified BB fit OK. I don't know because the frame came without a BB. The OEM BB is an FSA 386EVO with a plastic internal sleeve. I think that sleeve has a smaller OD than the Wheels Mfg BB we used.

That said, the insert for my frame was flush to the outside and inside surfaces of the BB shell, but the insert in my friend's frame was not, so the build may have been within specs but it wasn't consistent nor optimal.

All in all, things worked out OK. My friend's solution with the Dremel worked and his cover hasn't come off yet. A little Loctite on the cover bolt probably helped.

unterhausen

it's quite possible it was on ebay because of this issue. Although most companies would have had it destroyed.

Johno59

At 180 degrees C the resin holding the carbon fibers together comes under stress and the bonding will want to delaminate from the carbon fibers. Considering a blow torch is well over 1000 degrees C your ambitions for wanting the rigidity and lightness of a plastic bicycle will amount to nothing very rapidly indeed.

carlos danger

i have ****ing idea what you are describing here. you need to post pics.

as for heating anything on a carbon bike to remove it???
this is joke right? you are aware your carbon bike is mostly plastic right?

unterhausen

welcome to last year ya'll

don't defeat the censor please

Andrew R Stewart 

Especially when it seems that a key word is missing, "no". ( As in no XXXXXXX idea...) Andy

unterhausen

I edited the post so the censor would work ( you can see "last edited by unterhausen")