Strange effect and problem with 2K clear

Hi,

Experimenting with clear 2K I got strange effect which in fact is a problem with finish of my FW10.
I used Dupont Duxone and used Hiroboy's guidelines for painting. When wet coat was on the body everything looked fine. Looked like glass.

After about 15 minutes some very, very little holes/dimples have appeared. They look like someone made them using needle and delicately puncture surface.

If you look at the model from 15-20cm you can notice them only with strong light source.

Proportions of lacquer and hardener were measured precisely. I have added 10% thinner (Finishers Pure Thinner)

Body has been wet sanded and washed before painting. Fully dry, 24 hours in drybooth.

Any ideas?

Had a similar result myself when using the Finishers thinner with 2K. Now I use the base coat thinner exclusively with the 2K and so far everything has been fine. So it could be the thinner. Have you used it before with the 2K or is this your first try with it..??

Had a similar result myself when using the Finishers thinner with 2K. Now I use the base coat thinner exclusively with the 2K and so far everything has been fine. So it could be the thinner. Have you used it before with the 2K or is this your first try with it..??

First try with Finisher's. Previously I used Tamiya Lacqeur Thinner and it was fine.
Stupid, stupid, stupid :banghead: I should stick to Tamiya I have already tried.

I cured mine by lightly flatting out the offending holes until they were almost gone and then used Tamiya and Finishers compounds to restore the gloss...

I am considering to lightly sand whole body then lay down one more wet coat of 2K.

Anyway - thank you for help!

Those little dimples are called "fisheyes" and they are caused by Moisture, any kind of contamination on the surface of the model, or in the airbrush gun or air entering the gun. It is also caused when you apply the first coat too heavy and solvent popping occurs making those dimples. You will need to reclear and hope it does not occur again... Next time it happens... Keep clearing the car as normal.. Then take the jar you have hooked to the airbrush and dip a clean brush in the clear and Dab the fisheyes to fill them in. Then reclear on the next coat. The new coat of clear will melt the now raised dimples level. Even if they dont you can knock them down with sanding and polishing later.. its an effective way to save a 2K paintjob because once you clear the car with 2K there is no starting over..... 2K clear does not strip!!

DaveT

Thanks for the ideas! Still, I tend to belive that it is thinner issue. Why? Because I don't know how could I have much, much less contaminated environment. I have oilless compressor, 2 moisture filters inline, single use paint containers, drybooth and usually not hurry painting after washing model.

Anyway, one again - thanks for your help.

Mmmm, I not agree at 100% with Steve: fisheyes are caused by the thinner that try to evaporate. You'll get sure fisheyes (we call them "crater") by moisture or contamination, but you get immediatly, simply the clear can't stick properly on the surface in some points: typically you get them on resin parts poorly cleaned (and sometimes also on parts perfectly prepped, we're speaking of sylicon contaminations).

If you get craters after some time, after achieved a perfect surface the trouble would be the thinner: you must try to use a bit less thinner and build thin layers. BTW all you need is sand down a bit the part and re-coat.

PS Edit: with my crappy English whe I write "I not agree at 100%" I mean "I not fully agree" in the opposite sense of "I don't agree, fully" :D, fiuuwwwww...

when I write "I not agree at 100%" I mean "I not fully agree" in the opposite sense of "I don't agree, fully" :D, fiuuwwwww...
:rofl: :rofl: :evillol:

I see..... ;)

Happily I've catched the right meaning :)

My auto paint supplier recommends UR40 Medium Temp Reducer instead of lacquer thinner. I tried using regular lacquer thinner with base coats until I got a batch that curdled. Since then I've stuck with the Reducer and had no problems. I think the same would apply to any urethane, including 2K clear.

Next time I will use DuPont reducer and will see. This 2K could be sprayed without reducer but it seems a bit to thick to me and my 0.5mm airbrush.

i am dealing with the same issue now. it looks like more thinner is better than less because you can lay down thinner layer of clearcoat and thinner can evaporate better. with less thinner i need thicker layer to achieve uniform gloss - it is flowing/leveling better (thinner is orange peeled).
i untderstand that with 0.3 nozzle you have to have much thinned stuff than recommended so thinner needs to evaporate more and thick layer is not good for it.
hm...

Next time I will use DuPont reducer and will see. This 2K could be sprayed without reducer but it seems a bit to thick to me and my 0.5mm airbrush.

There are thinners for 2K clears?

Next time I will use DuPont reducer and will see. This 2K could be sprayed without reducer but it seems a bit to thick to me and my 0.5mm airbrush.

If you find a good source for good auto thinners in Warsaw, please let me know where it is! :D

There are thinners for 2K clears?

Yes, except they are called "reducers" and are available at automotive paint stores. (Except in countries where all non-waterborne paints are outlawed. But I'm not sure whether there are any such countries yet.) Reducers are used to thin all urethane paints. If you can't find a jobber in your area, you might be able to wangle some medium or low-temp reducer from a body shop.

Dupont and other manufacturers don't recommend the use of reducers with 2K clears. I believe this is because thinning weakens the coating and makes the finish less weather-resistant - not something we need to worry about. In my experience, thinning works just fine and is necessary because un-thinned 2K clear looks like syrup on the car and is too thick to spray unless you have a giant nozzle.

SkylineFan is absolutely right that 2K does not strip. Single-part urethane touch-up paint is easier to remove - not easy, but easier than 2K clear.

Ddms

Thanks again for yours answers!

One more question. I am going to respray with 2K. The surface is already sandend down and the question is:
Can I lay down just one wet layer or follow the procedure: mist coat, 5 minute brake, wet coat?

If the 2K is thinned, I'd start with the mist coat. If it's too wet, the thinner could damage the color coat.

:banghead:

I have tried 2K on FW10 again with 15% thinner added. I used proper Dupont thinner (for all bases and clears), body dry like Sahara and clean like House MD sense of humor :)

Effect? Still super small craters/holes. I have excluded surface contamination as I have cleared one part which has been painted TS26 before and never touched.

Maybe thinning is not good for this clear? :confused: Maybe drying temp is too high?

Maybe FW10 is cursed and I will never achieve decent clear coat?

This is my second approach to 2K and I thought that it would be much easier than using regular clear. Now, it looks exactly opposite...

Sounds like some sort of bad chemistry between the Duxone and whatever 2K clear you're using. Guess I'd try Duxone 2K clear.

Other than that, I'm plumb out of ideas except to forget about 2K clear and use U-POL or Tamiya TS13 synthetic lacquer clear coat. I love the results I get from U-POL, but it's not available everywhere. In the U.S., you can order it online at Sam Ditchek & Sons in Brooklyn, NY. But it's made in the UK, so it ought be be available in Europe.

Ddms

Well, me too - no ideas...

I used Dupont Duxone clear and Dupont Duxone thinner, so should be good.
Last idea I have is that I used samples of clear/hardener I got from paint seller. IF in the jar is defferent clear than Duxone... :) that would explain strange effects.

I didn't notice you live in Warsaw. So does Klutz, and he said he can't get U-POL there. I live in the U.S. and order it on-line from Ditchek.

Ddms

Some good news. I kept model in drybooth overnight and heat it up few times. The bad effect has dimnished, so probably I will just polish it up.
Next time I will use fresh clear and will report the effects :)

ok guys, so do we have some general rules how the crates are appearing? too much thinner, too thick clear via small nozzle etc..?

ok guys, so do we have some general rules how the crates are appearing? too much thinner, too thick clear via small nozzle etc..?

General rules
Rule #1: There are no rules
Rule #2: See rule #1 above

Right you are, Steven!

Anyway, I will test fresh opened can of Dupont clear both thinned and not. Will post results hoping it will give some directions...