Ducati Sporting Club UK > General > Idle Chat > Bonding carbon to carbon?

[neil748r]

Just finished making a repair to my Corse oil breather box and now have to bond the box part back onto the undertray.

Question is, what do I use?

The original "adhesive" is black, sets rock hard and looks like it is applied from a tube/gun (like what you would use to apply bathroom sealant etc). My usual resin supplier is in the dark here!

Any body have any idea what I should use? Obviously it has to be oil resistant.

Any advice much appreciated.

Thanks, Neil.

[antonye]

The black stuff is probably just a standard resin with some black applied to it to give it the colour - like a coloured gel coat.

I'd just use a standard West Systems epoxy, making sure you prep the two surfaces to get a good bond between them.

[Felix]

Whatever bonding system you choose, surface preparation is absolute key.

I have a fair suspicion the original stuff used by MS Production is a 3M product, most likely this one:
DP 460

Also, have a look at this site: Q&A Carbon Fibre. A quote from their site:

Q: Does it matter so much when using epoxies, so long as you prepare the cured surface correctly?
A: The surface must be carefully prepared for any kind of bond to perform as expected. When laminating with epoxy, I prepare a cured composite surface as follows:

Mechanically clean: remove stuff like paint, old bits of dried substances, stickers and their adhesives, decals, flapping plies, scale, crud, etc.
Chemically clean: remove grease and oil: fingerprints, grease from old bike parts, oil from the bike chain, etc.
One last wash: rinse and scrub with acetone until white paper towels come up clean.
If the substrate is metal, I sand blast it when possible or use 80 grit emery paper as a second choice. The idea is to develop a rough surface for the bond to key into. At the last second before it gets bonded I rinse it with acetone.
If the metal is aluminum, I use West System's two part etch kit. See http://www.westsystem.com/webpages/u.../index.htm#2.1 for West System's recommendations on special preparation for various materials. This nearly doubles the strength of the bond according to West. The idea is to convert the aluminum oxide that forms on raw aluminum. Aluminum oxide only takes fractions of a second after it is sand blasted to form, so there is no such thing as getting rid of the oxide by sanding it just before bonding.

And lastly read the warning at the bottom of the page.

[Edited on 8-6-2004 by Felix]

[Felix]

Here is some UK related information. Give them a ring:
3M Scotch-Weld

[Ray]

n748r,

I have just used boggo araldite, the stuff that comes in a pack with two tubes, painted it black afterwards. The only problem is that this stuff runs everywhere before it sets.

I made sure the surfaces were 100% clean using brake cleaner.

Ray.

[neil748r]

Thanks chaps,

West Systems is what I use for all carbon repairs, with great results!

To be honest it doesn't look like resin mixed with black colourant. When I eventually managed to get the box part off the undertray (so I could repair from the inside and make sure it was oil free) there was a "bead" of the adhesive which wasn't compressed when the two parts were originally bonded together (see attached pic). This is what makes me think it is applied with a gun. Looks exactly like the result of sealing your bath before you smooth it out. Also, the box is not a perfect fit so in places there is quite a void to fill. So whatever is used must be quite "thick" (ie not runny!) in order to not run out before it has cured.

Cheers, Neil.

[neil748r]

Thanks Felix,

I'll give 3M a call.

Cheers, Neil.

[Felix]

Neil, what repairs did you need to make?

I'll be interested to hear how you get on.

[Edited on 8-6-2004 by Felix]

[antonye]

Neil,

If you mix the resin first, you can leave it to part cure and use a (large) syringe to apply it and you'll end up with the same look as you have.

It makes the resin much easier to work with as it doesn't run anywhere.

Just remember that you'll be throwing the syringe away afterwards!

[neil748r]

Antonye, I'll give that a try - off to the vets to blag another syringe! My only concern is that if it doesn't work it'll be a nightmare to get the box off the undertray again!

Felix, the bike that I got the breather box off had been slung down the track so the undertray part had been snapped and cracked in a few places and there were big chunks missing. Also, the whole assembly had been shunted sideways so the box part had made contact with the subframe, result, three cracks on the top and split right the way along one side. I replaced the undertray part with a MS Production plain/road undertray. The only problem was that it was drilled for the number plate hanger, the two relays that sit under the seat and for the helmet hook thing, all of which are under the box part! So, I cut small discs out of the broken undertray and bonded them in, even lined up the weave so they're all but invisible. The box part I taped everything into the right position from the outside then repaired with resin from the inside. Very strong and invisible from the outside. All the repairs are oil proof, no leaks - I checked!

Apart from this latest project, I've also repaired carbon airboxes, huggers, front mudguards, heel guards, airtubes, bellypans etc etc. Usually the repair is almost impossible to see unless you look VERY closely. It only gets tricky if there are pieces missing although in that case I try to replace with a matching piece of carbon from my (small) supply of unrepairable parts.

Takes ages though!

I've attached a couple of pics, all the areas circled in red are where there were either holes, cracks or splits. All the parts still need a final couple of coats of clear to finish them off.

Cheers, Neil.

[Edited on 8-6-2004 by neil748r]