Problems spraying Carbon

[Mr Gazza]

I've just been trying to re-lacquer my Carbon.

The tea tray and side panels have turned out fine, but I am having trouble with pinholes on the front 'guard and Hugger.

I know that spray won't go into pinholes or fine cracks, so I stopped when they appeared, as putting more on just makes things worse.

I prepped all the surfaces with my favorite medium, a purple scourer pad. I just keyed the surface to an even dull tone all over, although I had given one area on the hugger a harder rub down with wet n dry, where high level silencers had chaffed (This area is unaffected with the pinholes).

Everything was wiped down with clutch and brake cleaner immediatly before spraying.

My gut feeling is that the pinholes are bubbles in the previous lacquer, that I have popped when I prepped. I also suspect that they may be contaminated by silicone wax.
I would have though that the C and B cleaner would have shifted any wax, but obviously not.
I have subsequently tried white spirit but that won't clean out the pinholes either.

I have tried to brush lacquer into the holes with a little artists brush, but they still turn into microscopic volcanos and seem to confirm my silicone theory.

I can't deny that I am i little bit cross about it, but I have come away to let everything harden off till tomorrow.

Normally I would press in knifing putty (fine filler), but that's not really an option unless there is such a thing as clear knifing putty (which there isn't.!)

Don't know quite what to try next. If it's bubbles in the old lacquer then a more meaningfull rub down might cut into a firmer substrate, but if it's the carbon weave that is porous that will make it worse.

Any advise would be gratefully recieved.

[utopia]

Well, I don't have lots of experience, but I have just relaquered a carbon seat cowl, and had good results.
My method was to rub down with wet and dry and lots of soapy water, in the hope of deep-cleaning the cowl as well as flatting the surface.
A good rinse with lots of clean water was followed by a couple of days hanging over the radiator to remove every last trace of moisture.
The final wipe down was with a cloth dampened with meths.
Then four successive coats of U-Pol clear No.1 at 5 min intervals.

I know what you mean about persistent pinholes though. Its almost like they have a magnetic repulsion for paint sometimes.
I wouldn't be at all surprised if there is some residual wax which is causing the problem. Maybe a vigorous scrub with a nailbrush and plenty of hot soapy water might shift it.
Solvent might dissolve any wax, but unless you flush it away completely, it'll remain when the solvent has evaporated, and possibly it'll tend to get flushed into any pinholes ?

I have sometimes found that spraying a little heavier helps, though of course you run the risk of runs. They can always be rubbed down if they're not too bad though.

[Mr Gazza]

Thanks for your thoughts Utopia, I have more or less come to the same conclusion today.

I found a couple of forums that were discusing this problem last night. One was a boating forum and the other was a bike one. The second was started by an unfortunate chappie like myself who had the very same problem with Carbon Hugger and 'guard from an ST2.!

There were many tips as to how to reduce the amount of small bubbles during the layup proccess, but Ducati have already bypassed that stage for me...It would seem to be quite a common thing.

I think I can assume fairly reasonably, from what I have read, that the bubbles are near the surface of the carbon and not in the lacquer. So I will be brave and cut in a bit deeper.

I had thought like you, Utopia, regarding soapy water versus solvents, and also chosen a nailbrush for the job. I will try with boiling or near boiling soapy water, in the hope of melting any wax, and also possibly causing a minor eruption from the pinholes due to the heat.?
....And you are right about drying it all out thoroughly before spraying..Reminds me a bit of Osmosis treatment for the undersides of GRP boats. Yes it is a slightly different thing, but I can glean from it.

The most consistant advise on the forums was just to keep putting the lacquer on and rub it back until the pinholes dissappear...Should start getting somewhere after about 4 coats apparently..

If it all goes tits up then the last resort will be a gun full of primer filler and I will have myself some coloured 'guards....Should look quite gay with a Red and Gold Hugger...

Buy some proper panel wipe off eBay it's only cheap.flat with 320 grit wet ,then flat again with 600 wet,leave to dry overnight then panel wipe with a Lint free cloth.make sure the room you spray in is warm ,put one coat on then leave for at least twenty minutes until touch dry,then apply more coats until happy with the finish
I won't spray anything unless it panel wiped 1st,hth

[jerry]

whats the best UV resistant laquer in a spray can ???I did my S4 in thailand 3 years ago but its dulled off again especially on the Silmoto silencers,,,,

[Darren69]

I was going to suggest steam cleaning as a method of melting any residual was, but if you can cut it back further this may solve the problem. I've just bought one of those VAC steam mops and was thinking it could be used for bike cleaning duties.

Jerry my carbon cans are yellowing too, I think it is much to do with the extra heat as much as the UV!

Originally Posted by jerry

whats the best UV resistant laquer in a spray can ???I did my S4 in thailand 3 years ago but its dulled off again especially on the Silmoto silencers,,,,

Upol is good stuff

[utopia]

I used U-Pol on the strength that it was expensive enough to be decent stuff.
But its seen no sunlight at all yet.
I'm impressed so far, though.
I put a basecoat on, and then applied graphics which I then lacquered over.
The can comes with a very fine nozzle, so it goes on smoothly anyway, but I was particularly impressed with the way the first coat(s) could be rubbed back to a deep lustre which gave the carbon fibre loads of depth.
It looked pretty shabby beforehand.
I haven't rubbed the finish coat(s) down yet, but its decent as it is anyway (by my standards at least) with only a little orange peel in the finish.

I'm hopeful....but time will tell.

[damien666]

Thin the clear coat down so it's not as gloopy? spray in thinner coats, so there's less surface tension so it has more chance of filling tiny imperfections in. Repeat a few times flatting down with wet 800/ 1200 wet/dry paper. thoroughly dry quickly so no flatting down resdue dries in the imperfections. Clean with spirit wipe/panel wipe and use a tack rag before each clearcoating session.
Just a thought on the steam idea, if it gets under and starts to lift existing clear, you will cause a headache!

[Mr Gazza]

Thanks for your help and support guys.

I hadn't heard of panel wipe but I have been useing clutch and brake cleaner or thinners and tak rag.

Yup, steam cleaning sounds like a recipe for more problems, but I did try a good scrub down with boiling soapy water, last night and then a rinse off straight from the kettle.

There didn't seem to be any adverse effects from that. After it had dried for a bit there seemed to be a lot of patches on the surface which I am hoping is the wax that has exuded from the pores.

It's been in front of the woodburner all night, so I am going to try a brushed coat of lacquer tonight.

I'm using a two part Upol lacquer.

btw, when I started rubbing it down last night, it revealed loads of pinholes that I had not seen before...Looked like a pin cushion..

[Mr Gazza]

Looks like brushing might be the way forward..

Just floated a coat on with my favorite little brush for painting model planes, and found that the spraying lacquer behaves very well.

As I hoped the mechanical brushing action does tend to work the lacquer into the pores, or maybe it's breaking the surface tension over the pores and just bridging them. Either way there is some progress and I might even get away with just one more coat before I can get the spray gun out again.

What is suprising, is how good the finish is with the brush, where there are no pores..This would definatly be an option if no spraying facilities were available.!

[Mr Gazza]

Just to finish this thread off....

I must admit that I did lose heart a bit, with the Carbon, but I persisted with the brushed coats and rubbing down with 400 in between.
The brush marks were very subtle and easy to rub away, and more pin holes were killed with every coat. It was possible to fill the bigger ones with lacquer from a very diddy little modelling brush, once the surrounding lacquer had formed a big enough "bowl" around the pin hole.

The lacquer sprays on very easily once the pin holes are sealed.
Once I had got a good sprayed coat on all over, I flatted off for the last time.
I masked for the stripe and blew on lacqueur with about 10% Gold base coat mixed in.
Judging how many coats of this is needed is VERY subjective.!
The masking was removed with the stripe still "green" and then clear lacquer sprayed on like Noah's flood.....Seems like you can never put too much on.

I finally got the finish I was aiming for...It's a sort of "Old Gold" look. When it catches the light at the right angle you can see the weave, but at other angles it looks solid....Just need to put a stripe on the tank to match and she's done...Bit of riding first though..

cracking job Gazza

[Mr Gazza]

Thank you Perkles, it means a lot coming from yourself.
Thanks for the tips along the way too.......

[Dirty]

That looks great!

Have you been attacked by Ninja's lately?