Need Help With 2K Clear

[CNB25]

I recently sprayed Nason 496-00 2K clear over Testors Extreme Lacquer that I decanted and shot out of an airbrush. The color coat looked great but when I shot the clear it caused some darker spots in the paint. I will try to upload some pictures later but any help in the meantime is appreciated!

 

The pictures of the bronco body are after the clear I hope you can see the spots I’m talking about. The 1990 mustang is what the bronco looked like before the clear.

Edited January 12, 2023 by CNB25

[stitchdup]

The darker spots may have been in the colour coat but not as visable until the clear went on. Clear can magnify the paint its used on in the same way black is more likely to show these things. I find taking paint that needs clear out in the sun or under a flouresant light for a check before the clear goes on helpful to see these things as other indoor lighting doesn't really show some things that well

[70mach1]

Looks like bad or no primer is the cause. did you prime?

[CNB25]

No sir I did not prime it did not even think of that I will strip it down and spray primer tonight 

[Ace-Garageguy]

No mystery here.

The solvents in the 2K re-wetted the metallic lacquer underneath, allowing the metallic particles to fall over into the pigmented clear carrier, thus losing their reflectivity and causing local dark blotches.

Either (1) the Nason 2K is just too "hot" to be used over the Testors lacquer, or 2) the 2K was applied way too wet, attempting to get it to flow out glossy, or 3) the application of the clear OR the green was uneven and too heavy in only the areas where the dark streaks appeared (which is what I suspect), or 4) the green just wasn't sufficiently dry prior to shooting the clear.

If you've used this particular combination of products before with no problems, it's an application issue with this particular job.

If you have NOT used this combination of materials before, this is why we continually preach "test any new combination of materials, or any change in technique, on something you don't care about BEFORE you paint a good model".

This is also the reason we preach the wisdom of using products that are designed to work together.

Big-car metallic basecoats are specifically designed to NOT re-wet and go mottly when urethane clears are applied over them, but without testing the Nason clear sufficiently over the Testors metallic lacquer basecoat, things like this can happen.

A good primer under everything, over properly prepared plastic, MAY OR MAY NOT have an effect on the stability of the green metallic, but without testing, you're playing Russian roulette with any paint job.

 

Edited January 13, 2023 by Ace-Garageguy
CLARITY

[Dpate]

Well i was assuming you didn't prime because of the paint you used is a 3 in 1 type.  Paint, primer, & sealer.  

[Ace-Garageguy]

  On 1/13/2023 at 12:54 AM, Dpate said:

Well i was assuming you didn't prime because of the paint you used is a 3 in 1 type.  Paint, primer, & sealer.  

Expand  

What the eff?

Testors "Extreme" lacquer is simply the old "One Coat" lacquer, relabeled with a moronic "extreme" thrown into the name, and a marketing claim that it eliminates the need for primer and sealer because it's not particularly "hot" as lacquers go.

For optimum performance, it's always needed primer.

This is the stuff, with Testors lacquer clear...all over Duplicolor primer

 

Edited January 13, 2023 by Ace-Garageguy

[Dpate]

  On 1/13/2023 at 1:03 AM, Ace-Garageguy said:

What the eff?

Testors "Extreme" lacquer is simply the old "One Coat" lacquer, relabeled with a moronic "extreme" thrown into the name, and a marketing claim that it eliminates the need for primer and sealer because it's not particularly "hot" as lacquers go.

For optimum performance, it's always needed primer.

This is the stuff, with Testors lacquer clear...all over Duplicolor primer

 

Expand  

I know. I'm saying i assumed HE didn't prime because of what the can said.  Probably thought you could get away without using primer.  

[Ace-Garageguy]

  On 1/13/2023 at 1:18 AM, Dpate said:

I know. I'm saying i assumed HE didn't prime because of what the can said.  Probably thought you could get away without using primer.  

Expand  

If you've been around for a while, you will have seen a lot of models painted with that stuff, over bare plastic with no prep.

The giveaway is usually odd looking panel edges and door lines where the paint has pulled away from the edges and almost puddled, leaving dark areas.

HOWEVER...that is not a sufficient reason to assume that a lack of primer in this case is the cause of the problem.

Assumptions based on insufficient data aren't usually very helpful.

Still, learning to prep prior to paint helps in getting good paint jobs, but TESTING with unfamiliar combinations of products not designed to work together is of primary importance.

And don't always believe everything that it says on a can...or what some internet expert says.  

Edited January 13, 2023 by Ace-Garageguy

[peteski]

To me it looks like the metallic paint was not applied evenly over the entire body. Visually the coverage looked solid and even, but some areas have a heavier coat of paint.  Then the clear partially dissolved the base layer of metallic green and some of the metallic particles and green dye got into the clear.  That is why there are color variations.  Or maybe the clear was applied unevenly and where it was applied heavier it partially dissolved the metallic green.

If you look at the darker areas around the door line edges, you can see different color (as if the green paint was pulled from those areas).  I'm also not sure if primer would have prevented this.  The bottom line is that stripping and repainting seems to be the only option.

Edited January 13, 2023 by peteski

[Michael jones]

  On 1/12/2023 at 11:14 PM, Ace-Garageguy said:

No mystery here.

The solvents in the 2K re-wetted the metallic lacquer underneath, allowing the metallic particles to fall over into the pigmented clear carrier, thus losing their reflectivity and causing local dark blotches.

Either (1) the Nason 2K is just too "hot" to be used over the Testors lacquer, or 2) the 2K was applied way too wet, attempting to get it to flow out glossy, or 3) the application of the clear OR the green was uneven and too heavy in only the areas where the dark streaks appeared (which is what I suspect), or 4) the green just wasn't sufficiently dry prior to shooting the clear.

If you've used this particular combination of products before with no problems, it's an application issue with this particular job.

If you have NOT used this combination of materials before, this is why we continually preach "test any new combination of materials, or any change in technique, on something you don't care about BEFORE you paint a good model".

This is also the reason we preach the wisdom of using products that are designed to work together.

Big-car metallic basecoats are specifically designed to NOT re-wet and go mottly when urethane clears are applied over them, but without testing the Nason clear sufficiently over the Testors metallic lacquer basecoat, things like this can happen.

A good primer under everything, over properly prepared plastic, MAY OR MAY NOT have an effect on the stability of the green metallic, but without testing, you're playing Russian roulette with any paint job.

 

Expand  

You are correct. I had this happen myself once trying to get a shiny finish. Simply too much 2k clear too fast. Reactivated the base coat....  especially likely if the base coat was sprayed a short time before the clear.