Problem with Tamiya TS-13 Clear

[David G.]

I'm also posting this in the build thread to increase the odds of getting an answer.

OK, I have a bit of a problem.

In anticipation of applying a clear coat to this model I masked off all the flat black trim.

 

I did a test on a couple of the smaller parts to  check compatibility and it looked great.

 

So I thought I was good to go and decided to start with the smaller nose clip and this happened.

The coat (Tamiya TS-13) laid down unevenly with a couple of rough patches. I applied two or three more coats and things improved a little but not by much. 

I don't use clear coat often but I have used it before. I know that sometimes it will lay down looking like it has soft fisheyes but will almost always even itself out in about 10 or 20 minutes. This one didn't.

And the rough patch; there were two, one on each of the two blue areas. The one on the right smoothed out after a couple of coats but the left side one stayed rough.

Prior to painting, I cleaned the entire car in the same manner using Novus Plastic Clean and Shine. Followed of course, by a thorough buffing with a soft polishing cloth. I've never had any problem painting over Novus polish until now.

I think I can smooth and polish the nose piece after it cures but I'm understandably reluctant to shoot the body. So it's masked... and waiting. Waiting until I find a solution to whatever this problem is or I decide to unmask it and proceed to final assembly.

So, um... Help?

I would appreciate any observations or suggestions.

Thanks so much,

David G.

Edited July 17, 2021 by David G.
Information Update

[MrMiles]

the only time i have personally experienced this was when painting on incompatible types of paint. one was a acrylic and the other was enamel. however, its odd that half of the same piece had the reaction.

im interested to see what others say

[Tom Geiger]

You didn’t identify the paint under the clear.  It may be the Novis Polish.  I’ve never had an issue with Tamiya Clear.

[Claude Thibodeau]

Hi David!

Well, never had such reaction with the TS-13, even when applying MANY coats in one session. The only suspect, IMHO, would be your use ov Novus clean and shine. The "shine" part might be the culprit. If you had a bad can, your first parts would have presented the same outcome. 

Even if is a pain in the neck, washing your remaining parts with a damp cloth treated with a drop of dishwasher soap might do the trick, without soaking your masking job. 

Finally, as you may know, it is counter-indicated to make successive TS-13 application in a short span, such as the next day or the day after. They recommend waiting 30 days (!?!) before a second coating. So, it's all in one day, or a loooooong delay between clear sessions. It sounds extreme, but I paid the price for defying this common wisdom among Tamya's users. Never again. 

Good luck!

CT 

[David G.]

32 minutes ago, MrMiles said:

the only time i have personally experienced this was when painting on incompatible types of paint. one was a acrylic and the other was enamel. however, its odd that half of the same piece had the reaction.

im interested to see what others say

 

27 minutes ago, Tom Geiger said:

You didn’t identify the paint under the clear.  It may be the Novis Polish.  I’ve never had an issue with Tamiya Clear.

Miles and Tom, thanks for your response.

The only paint on the part in question is the orange, Tamiya TS-12. The blue is actually the color molded plastic. All of it, including the test pieces, were cleaned with Novus.

I even did a test on a scrap body using the exact process I planned for the Ford. I washed the scrap body with dish soap and running water, allowed it to dry, then cleaned it with Novus and buffed it, When I sprayed it with the clear coat, it first showed a little unevenness which leveled out in about 20 minutes.

 Aside from the scratches and other flaws in the plastic itself, smooth and shiny. Which is why I'm so dumbfounded.

27 minutes ago, Claude Thibodeau said:

Hi David!

Well, never had such reaction with the TS-13, even when applying MANY coats in one session. The only suspect, IMHO, would be your use ov Novus clean and shine. The "shine" part might be the culprit. If you had a bad can, your first parts would have presented the same outcome. 

Even if is a pain in the neck, washing your remaining parts with a damp cloth treated with a drop of dishwasher soap might do the trick, without soaking your masking job. 

Finally, as you may know, it is counter-indicated to make successive TS-13 application in a short span, such as the next day or the day after. They recommend waiting 30 days (!?!) before a second coating. So, it's all in one day, or a loooooong delay between clear sessions. It sounds extreme, but I paid the price for defying this common wisdom among Tamya's users. Never again. 

Good luck!

CT 

Hi Claude.

I thought about washing it again but I am a little concerned about what may happen to the decals if they get wet. Regarding the multiple coats, they were all laid down within about an hour and a half so they should have bonded well with each other.

Thanks for all the responses. I'm still not sure what path I'll take with this yet but I sure don't want to take a chance at ruining it at this late stage. 

It won't do any harm to let sit with overnight with the masking while I sleep on it and see what other suggestions I receive.

Thanks again, 

David G.

[peteski]

I have *NEVER EVER* used anything but water and good dishwashing detergent to clean the parts before painting, and I never will!  I would not trust any sort of "cleaner" or "treatment".  I'm not sure where people get the idea that some other compound is is needed *BEFORE* painting.

If decals are dry (I give them few days), it is safe to wash the decaled part with water and dishwashing detergent.  Take a 1" soft natural hair brush, wet the bristles, then squirt little detergent on the bristles. Then I work up the lather by rubbing the bristles on my palm and gently brush the decaled part to be cleaned.  Don't spend too much time doing that. Then I rinse it off using warm running water from the faucet. Then dry the part blotting (not wiping) the part with a towel. I suppose microfiber cloth might work well too.  If there is some moisture left, I just let the part air dry.  If there is any lint or fuzz left after it is dry, I blow it of gently using compressed air (the "canned air" in aerosol cans works good, or just compressed air from your compressor). After that the pert is ready for a clear coat.

However, after seeing the problem you experienced it might not just be Novus - maybe the clear coat is attacking/crazing the plastic?

[David G.]

10 hours ago, peteski said:

I have *NEVER EVER* used anything but water and good dishwashing detergent to clean the parts before painting, and I never will!  I would not trust any sort of "cleaner" or "treatment".  I'm not sure where people get the idea that some other compound is is needed *BEFORE* painting.

If decals are dry (I give them few days), it is safe to wash the decaled part with water and dishwashing detergent.  Take a 1" soft natural hair brush, wet the bristles, then squirt little detergent on the bristles. Then I work up the lather by rubbing the bristles on my palm and gently brush the decaled part to be cleaned.  Don't spend too much time doing that. Then I rinse it off using warm running water from the faucet. Then dry the part blotting (not wiping) the part with a towel. I suppose microfiber cloth might work well too.  If there is some moisture left, I just let the part air dry.  If there is any lint or fuzz left after it is dry, I blow it of gently using compressed air (the "canned air" in aerosol cans works good, or just compressed air from your compressor). After that the pert is ready for a clear coat.

However, after seeing the problem you experienced it might not just be Novus - maybe the clear coat is attacking/crazing the plastic?

Thanks for the input Peter. Given my prior experiences and what you're telling me here, I tend to agree that the clear coat may be crazing the plastic. If that's the case then I think it's best that I don't make any further attempts with the Tamiya TS-13. The model looks pretty good now and I'd rather not take a chance at ruining it this close to completion.

But in the future, I'll certainly adhere to your recommendation for relying on the more traditional cleaning method. You just can't go wrong with good ol' soap and water. 

I do have a bottle of Pledge acrylic that I could try, I've had good luck with that in the past. But at this point I'm just inclined to remove the masking, clean up the nose clip in a few days after it cures and push toward the finish line.

Thanks again,

David G.

[Zippi]

I use the Tamiya paint and TS-13 and never had an issue that looked like that. My process is to wash the body in dish detergent and dry, paint the body with light coats allowing it to flash 20 between coats.  When I spray the TS-13 I do the same as when I sprayed the paint except I give it one final wet coat at the end.  Have to be careful as there is a fine line between wet and running.  

[Plowboy]

I'm thinking you may have sprayed too much at once. Whether I'm spraying paint or clear, I never spray more than two coats per day. With clear, I spray two coats one day. Next day, sand with 2000 and spray one or two more coats. Allow it to cure, sand and polish. 

Most times, the way my paint jobs work out is I spray two coats of paint, dry a day, sand with 2000, spray a coat of paint and a coat of clear, dry a day, sand with 2000 and spray two coats of clear. Not always. But, most times. 

[Tom Geiger]

15 hours ago, David G. said:

The only paint on the part in question is the orange, Tamiya TS-12. The blue is actually the color molded plastic. All of it, including the test pieces, were cleaned with Novus.

This could be your problem.. clear on bare plastic. The Tamiya clear is designed to be sprayed over their paints.  The absence of primer / paint coats may be the issue.

 

[David G.]

Thank you all for your input, I gained quite a bit of knowledge from the responses I received.

It seems to me that this issue was most likely a combination of some crazing of the plastic and me applying too thick of a coat with some possible interaction with the Novus polish.

I've decided that rather than risk any more issues, I'm just going to repair the finish on the nose clip as best I can and proceed with final assembly.

Thanks again,

David G.

[David G.]

Just a quick follow-up.

I sprayed a couple more coats of TS-13 noticing that the finish smoothed out a little more after each coat. After curing, I used  Micromesh polishing and finishing pads to smooth and polish. Everything worked as well as I hoped it would.

 

Thanks again to everyone who offered advice and information... and encouragement, which is often the most important part.

David G.

 

[peteski]

Thanks for following up. The repair came out really well.

[Rick L]

What is your reasoning to buff before clearcoat and not after?

[TransAmMike]

23 minutes ago, Rick L said:

What is your reasoning to buff before clearcoat and not after?

Similar question here.  Did you spray clear directly over the polish?

[David G.]

15 hours ago, Rick L said:

What is your reasoning to buff before clearcoat and not after?

 

15 hours ago, TransAmMike said:

Similar question here.  Did you spray clear directly over the polish?

Hi Rick and Mike.

I don't use clear coat often but the last few times I did, I did use Novus #1 Plastic Clean & Shine solution prior to doing so and the results were great. I have also used it many times between coats of paint when sanding out or repairing imperfections. 

The main reason I tried it in the first place was due to static electricity and water scale. Where I live our tap water has a high mineral content such that letting plastic parts air dry after washing them frequently leaves rather stubborn water spots and washing with distilled water just isn't practical.  I found that Novus Clean & Shine was great at removing the water spots and really cut down on dust attraction.

It looks like I may have to review and revise.

My reason for buffing before the clear coat is to smooth the surface as much as possible before the final coat, whether it's a clear or color coat. Once the paint cures, I buff it for a final time.

Regards,

David G.

[Rick L]

That is very interesting. Perhaps you could dab a dust free cloth with a final swipe of distilled water after washing with the mineral water. A 12oz. bottle  would last quite a while. 

[David G.]

21 hours ago, Rick L said:

That is very interesting. Perhaps you could dab a dust free cloth with a final swipe of distilled water after washing with the mineral water. A 12oz. bottle  would last quite a while. 

Thanks Rick, I'll give that a shot.

David G.

[PatW]

To me any polish used goes on after all the paint and clear coats not before or during the spray up. The waxes if any in the different types of polish react to any type of paint whether it be acrylic or enamel.