31 replies to this topic

[Ste]

Hi all, i wonder if anyone can help with an issue I am having with my first paint project. Last year I painted my Mayfair with metallic 1K acrylic(?) laquer (basecoat and clearcoat). The car was 90% bare-metal, so etch-primed, primed and then 5 basecoats applied with flatting inbetween. There was no odd paint reaction at any of these stages and it looked good and smooth. One more coat of paint was applied prior to the clear coat with approx 15 minutes drying time inbetween.

After 3 coats of clear it looked a decent finish and it was left to dry in the garage for a fortnight. There was absolutely no reaction in this time. It was then wet sanded with 1200 grit, then G3 and G10 paste on an electric polisher, polished and waxed. Within minutes a few lines appeared in the paint on one area of the car which looked like hairs stuck in the laquer. As the days went by these spread throughout the car and now it is almost covered in a finish that resembles a cracked egg. It doesn't fall off or peel and seems to be just below the surface but it looks awful. I thought it was a problem with paint compatibility and took it back to the supplier. He did a test card and let me take it home to flat and polish. The same thing happened to one test but not another but he has no idea what the cause of it is.

I started my Park Lane a few weeks back and just finished the numberplate light housing as a test, this time in a pearlescent version of the same laquer and about a week after finishing a similar thing happened. The weird thing about it is that it only ever happens after the final colour-sanding and polishing and then only days after finishing that, every stage inbetween goes just fine. I am at a complete loss as to what has caused it and now have 2 unfinished Minis sitting there until I can come up with a solution!

What I will say is that the garage isn't heated constantly so it has fallen below freezing overnight at times, although spraying has been done at above 15 degrees c. It doesn't seem to have had any effect on the paint applied so far on the second project (5 coats primer/3 coats basecoat, now a month old and flatted ready for next 3 coats) Any ideas would be really helpful! Photos are available if required?

Thanks

[Big Guns]

Hi Steve,
The only thing I can think of is damp under the final coat. When you did the final clear coat was it cold? The only other thing that springs to mind is the possability of silicon from the polish reacting adversely with the clear coat.

[Ste]

Hi Steve,
The only thing I can think of is damp under the final coat. When you did the final clear coat was it cold? The only other thing that springs to mind is the possability of silicon from the polish reacting adversely with the clear coat.

Thanks, I did have concerns about whether the wax could have caused it, but it seems such an extreme reaction. I was also worried about whether fairy liquid in the water I used for flatting could be an issue. The only time it was really cold was overnight but by then the paint was dry to touch and the garage isn't damp at all.

[jack_marshall]

Hard to say without seeing it.

Why were you flatting your basecoat between coats? Theres really no need unless you get bits of crap or a mark appearing, should just apply it till covered then a couple more coats to be sure then clear.

[panelbeaterpeter]

How strange.. All I can think of, is the lacquer warmed up when you polished it, and either the primer or base coat wasn't fully cured, and something has moved underneath.. It would probably be the primer or the primer reacting to the etch.. did you prime the test card which reacted the same?

[Ste]

Why were you flatting your basecoat between coats? Theres really no need unless you get bits of crap or a mark appearing, should just apply it till covered then a couple more coats to be sure then clear.
[/quote]

Just following instructions from several sources to even out the metallic and get it as absolutely perfect as possible.

[Ste]

How strange.. All I can think of, is the lacquer warmed up when you polished it, and either the primer or base coat wasn't fully cured, and something has moved underneath.. It would probably be the primer or the primer reacting to the etch.. did you prime the test card which reacted the same?

As far as I know the supplier primed the card first but didn't bother to flat anything. Very much doubt it was etched first though. It probably wasn't the same primer that I used but he used my basecoat and clearcoat. The wings were in good condition paint wise so i only gave them a rub down and then put a layer of basecoat on top to get a good colour match and that was the first area to start deteriorating. The rest of the car quickly followed although these parts had been primed fully.

[Big Guns]

Sad as it sounds, I was thinking about this last night! It can ONLY be a reaction between either the original paint and your new primer (triggered by the clear coats solvents) or the primer and etch. If it hardened in the cold it may not have cured properly on the contact surface. Once a fresh solvent is introduced...ie the clear coat, it set off the reaction. Phew....hope that makes sense!

Edited by Big Guns, 29 January 2010 - 10:58 AM.

[cooper_shaz]

Hey,
Can you put a couple of pictures up so we can see what it looks like. From what you say it could be too many coats of paint too fast. when the paint dries it essentially shrinks as the solvents evaporate. This sounds like the solvents are evaporating from underneath and this causes what looks like a crack in under the surface.

There should be no need to flat out the base coat before clear unless there is a run, but i doubt that has caused what you are describing. !5 mins dry time between coats may not be enough but that depends on the temprature of the garage when you were painting.

If you could put some pictures up we can have a look and see if we can help.

[GraemeC]

All you assumptions are based on the OP's car, original paint, method etc. None of which would be a factor in why the test card, painted by someone else with no existing paint underneath, would cause the same outcome.

So, I would assume it is a function of the wet sanding and polishing or there is a materials incompatibitly in the products you are being supplied.

[Ste]

Thanks for all your ideas! Sorry Big Guns for interupting your evening!

pictures on the way.

Attached Files

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•  Gizmo_and_Goodwood_09_028.jpg   38.72K   36 downloads
•  Gizmo_and_Goodwood_09_026.jpg   34.6K   31 downloads

Edited by Ste, 29 January 2010 - 02:10 PM.

[djdobson]

it sounds like silicons have affected the laquer. im sure people have already suggested this. you need to use polish or wax without silicons in and maybe give the car more than 3 coats of laquer. i am not sure why it has done it after drying. all i can presume is that there were some light silicons under the laquer and when grit and polished it has disturbed the paintwork.

[Ste]

it sounds like silicons have affected the laquer. im sure people have already suggested this. you need to use polish or wax without silicons in and maybe give the car more than 3 coats of laquer. i am not sure why it has done it after drying. all i can presume is that there were some light silicons under the laquer and when grit and polished it has disturbed the paintwork.

Is it possible for the silicon in the wax that was applied at the end of the process to attack the new paint? I used Meguiars Gold Class wax on the original car, on the part from the 2nd car and on the test card (i think). The only other compounds that were used on all were the G3, G10 and a bit of T-Cut. The test card shouldn't have had any silicon on it at the suppliers. The second test he did that came up ok was polished by him and probably not waxed. Probably clutching at straws here but it would be nice if that was all it was! Does panel wipe clean off previous wax layers? I used loads in prepping the car.

[Svee]

I always thought silicon in the air/in a product applied on the surface caused something called "Fish-eye" which looks like this...


Im no clearing expert but to me that looks like checking/crazing which can be caused by extreme temps (too cold or when you were buffing it got too warm) or not letting the underlaying coat of primer/paint or clear cure to the right dryness before applying the next coat. If the garage was cold chances are the paint/clear didnt cure fully. You also need to leave sufficiant time between coats. 5 mins @ 15 degrees seems a little quick to me.

I hate clearing, problems can take forever to show themselves. You finish something and think you are on to a winner then something like this happens. Hope you get to the bottom of it mate and can sort it out without too much of a headache.

This link might be interesting reading...
http://www.briansmod...als/tutorial/30
Its on clearing model cars but he goes through a load of different clear issues that can happen on anything be it a model car or a full size one. Of course, full size cars are a different animal to models but as i say, makes interesting reading none the less

Edited by Svee, 29 January 2010 - 07:09 PM.

[panelbeaterpeter]

It has nothing to do with silicone. Silicone causes adhesion problems and fish eyes, which push the paint away from the contaminated area, making a little dip in the paint. It's a chemical reaction of some kind, it shouldn't be from the coats being applied too quick, or not enough drying time between coats, as it was 1k, it would evaporate through the lacquer, as it dries through evaporation rather than a chemical reaction, as per 2k, so any solvents would evaporate through the lacquer. If there was a massive build up, it could evaporate too quickly, and cause popping making the surface look matt, but wouldn't cause crazing like that. I'm really stumped on this one