Re-bonding carbon

[Simon Potter]

Help my rear dropout needs rebonding in my carbon swinging arm does anyone know of a UK  based company who could do the job (must be high quality) I'm desperate many thanks, Simon. [smiley=laughing.gif]

[GET]

Others know more details about this, but I can tell you that there is a thread on this subject in the old forum (see link to the left.)   Basically, others have cleaned the dropout and swingarm cavity.  Off the top of my head, I'd suggest acetone as the cleaner (although there are stronger possiblities.)  Then you can epoxy them back together with a high-strength epoxy.  I don't think you'll have to have someone else do it unless you really want to.  Let a few others reply before you get started, as I'm sure there are more useful suggestions available.

[GrimJack]

Nope, Get pretty much has covered it.  It's a very simple repair, you should have no problems doing it yourself.

[Scott]

Thanks goes out to Steve Klassen here  (worthy of our "How Tos" ? )


I've put information on the site before but it seems that everyone wants to

wax eloquent about the different possible bonding agents and I'd rather

answer this offline.  If you're building a fighter plane various bonding

agents might be important but it's a bike.  I've personally re-bonded 3 out

of 4 lugs on my swingarm.  I'm probably the only one ever to have done that.

The front drive side went first, then the rear drive side and then the front

non-drive side.  Since I've rebonded the lugs, not one has come loose and

I'm up to twice the time of the original bonds.  I ride my bike harder than

ever now.

The key here is not to remove the existing epoxy from the inside of the

swingarm after the lug is removed.  The epoxy is still attached quite well

to the inside of the swingarm and provides a good surface with which to

adhere.



Steps:

1) Rough up the inside of the swingarm with coarse sandpaper

2) Rough up the outside of the lug





Note:   Don't bother removing the existing epoxy since it will allow the lug

to be aligned to its original position once re-installed



3) Clean both surfaces with Naptha (sometimes called white gas, camp-stove

fuel etc) to remove all traces of oil, wax and/or silicone products.  Laquer

thinner also works.

4) Mix up your favorite epoxy - I used off-the-shelf clear 5 min Devcon

epoxy

5) Apply the mixture to both surfaces and insert the lug to its original

place



While curing, to ensure no misalignment, I put the swingarm onto the bike

with no shock attached, tightened all the front pivot bolts while supporting

the rear of the arm in a normal position.  The idea here is that after the

epoxy cures, the two front lugs are perfectly aligned in the pivots with no

added stress.

For the rear lug when it came loose I just clamped it to its original

position while it cured.  It seemed to work OK.



For even more strength:

If you feel adventurous, drill small holes in the aluminum lug so that the

epoxy has more of a mechanical bond with the lug.  I did this on my front

Drive-side lug since it has the most stress.  That new joint has now lasted

3 years.



Total cost of all 3 repairs -- $5.00 Canadian and my time.



Happy gluing.

Steve Klassen.

[Simon]

Thanks for the advice should be out on the trails again very soon. Simon.

[GrimJack]

I've made this a sticky - I'll drop it into our FAQ and the HOWTOS asap.

Thanks guys!

[numbnuts]

as I am the one who got this post sticked I thought I'd post a follow up. I bonded my swingarm dropout [evo4] with some "steel epoxy" that cost $3 at my local gas station. It had a 24hr recommended curing time which should be stronger than the 5min stuff I reckon. Cleaned the surfaces with some industrial paint thinner that we had lying around. that was 3 weeks ago and it seems fine still. Supergo did offer to warranty and actually extended their usual 12 mth period by a couple of weeks to accommodate me. But as I will be riding in NC next week I decided to use a lbs in Asheville who are listed as K2 dealers on the K2 site. They are not dealers anymore but were quite happy to deal with the warranty issue. I should have a new aluminium swingarm waiting for me to put on when i arrive, at no cost other than shipping and labour. The chap in the Lbs said that everyone who bought Evo's with carbon swingarm from them had a debond problem. He also reckons that K2 has a lifetime warranty for that problem which is pretty cool.I will repost in a couple of weeks with the outcome.

[Scott]

So you're allowed to keep the carbon arm AND pick up a new alloy arm?  That's quite a good deal!

[numbnuts]

SCOTT,

I assume that when I pick up the new swingarm I will have to leave the old one BUT if I can keep both I will. I guess usually one leaves the knackered part at the time of the complaint but as I am in Jamaica and my 'LBS' is in NC that wasn't an option. I will let you know how it works out, knowing my luck it will be a disaster but I'll be having too much fun riding Pisgah to care! [smiley=nod.gif]

[numbnuts]

hey things worked out well, I now have a bright yellow alum swingarm with disc adaptor and a spare carbon swingarm and hanger. All I ended up paying was $10 labour. Nuff respect to Ben at Ski Country Sports in Asheville for sorting this out, and to K2 obviously. I did end up spending a lot of dosh in the same shop throughout the week so everybody was smiling