erikrhendrickso

Hey Everyone,

Thanks in advance for your time. Been restoring a 1987 Trek 2500 with full Dura-Ace for my brother's birthday.

The carbon tubes has some bubbling near the lugs just under the clear coat.



I've sanded down the clear to get the bubbles out. Now I'm wondering what kind of clear to use?

Enamel, lacquer, or something else? Any suggestions?

Also, what kind of buffing compound(s) should be used?

Any web links to sites detailing the process would be great.

Thanks again,
Erik

HillRider

Those Treks had the carbon tubes bonded (read glued) into the aluminum lugs. Trek did a pretty good job of insulating the carbon tubes from the aluminum lugs to avoid destructive bimetal corrosion which would destroy the bond but if the insulation has broken down with age and perhaps water exposure, those bonded joints could be weak. Those bubbles are abnormal and can be indicative of some serious problems.

Andrew R Stewart 

Agreed that this frame's joints are becoming compromised. But i will say that I've seen far worse still on the road. If your bro is the careful type and actually takes the time to clean his bikes routinely i say ride the bike but monitor the joints. If your bro is the put it away slimy then just pump up the tires the next time type then don't let him ride it. Andy.

erikrhendrickso

K cool. Yeah I definetly will monitor the joints as he rides it. He really doesn't ride at all, but that's because he doesn't have a bike, and a GF. Hoping to get them both on bikes and riding.

If the joints get worse, I'll prolly end up getting new tubes all-around. I really just like the process of bringing these older bikes back to life. This one's been a challenge for sure.

Still looking for brake lever hoods (BL7400) and brake barrel adjusters and small parts(br7400).

Thanks

Looigi

You gonna spot touch up the clear coat or due all the tubes? I'd use two-part automotive polyurethane clear coat if doing the entire length of the tubes. This stuff needs proper surface prep, a HVLP spray gun, is toxic, etc... so read up before proceeding.

HillRider

Do you mean you are going to replace and rebond the carbon tubes? How are you going to do that and where are you going to get the new tubes? Also, the corrosive damage is to the aluminum lugs, not the tubes.

If the joints get worse, plan to replace the frame entirely.

erikrhendrickso

Just going to spot touch up...the rest of the tubes are fine...just the first 1-2 inches are where it needs to be re-cleared.

Popeyecahn

You might want to cross post this over at the Classic and Vintage subforum, there are a number of members that typically are found there that have Alans, Vitus and Peugeots built with carbon bonded/Al lugged frames (Chombi most notably).

stevoo

One word of caution
Do not power buff the lugs. My neighbor did that and the lugs got hot during buffing, expanded and disbonded all of the joints.
It was interesting when he went to ride the bike. The joints actually separated during the ride.

HillRider

Exactly, right adjacent to the carbon/aluminum interface. Again, use caution when riding this bike and pay attention to the joints.

Al1943

You can test the joints by trying to twist the tubes near the joints. If any twist loose the fame is done.
As for a clear coat I would mask off the lugs and use a rattle can of polyurethane being careful to shake the can well and keep it on the move to avoid runs.

Looigi

Suggest good automotive lacquer in that case.

BikeWise1

The two joints I most often saw fail on these frames was the head tube to downtube joint, and seat tube to bottom bracket joint.

erikrhendrickso

Thanks for the help with all this.

Went ahead and re-cleared the areas after masking off the lugs.

On to Buffing...anyone have suggestions. Obviously no power buffing, so itt'l be by hand with cloth strips and compound most likely.

Any specific brands?

Al1943

For general purpose jobs I use Dupont white polish (not rubbing compound). It's not expensive and you can buy it almost anywhere.

Popeyecahn

Mother's Mag polish.