Paint reaction

[Neo]

HI guys, quick question, 

 

i painted the green part of my chippy ho, the plane is painted in these steps

 

1 Mr surfacer black surface primer

2 AK Real color laquer 252

3 mr color laquer 66 green. 

 

on my first pass i had some paint flaws so i wet sanded with 4000 and 6000 paper, this section was sanded back down to the primer, it had a similar flaw show up in the same spot, now the fresh coat had the same reaction. 

 

I really want to understand what can be causing this

 

Any ideas ? 

 

[James Rademaker]

Any oil from your fingers? 
Jim

[Neo]

i thought about that but the same spot twice even after wet sanding. i did omit cleaning with alcohol before painting 

[Scale32]

Probably a reaction with the fresh paint edge and a little heavy handed. The fresh solvent will lift it.

 

Hth cheers Bevan 

[quang]

If you see the same flaw on the primer when the paint coats have been sanded off, the problem comes from UNDERNEATH the primer coat, notably the plastic surface. It could be something on the plastic which prevents the primer to adhere properly like a greasy spot.

[LSP_Kevin]

It's contamination of some sort, no doubt.

 

Kev

[Neo]

Thanks guys for the comments guys 

 

 

8 hours ago, Scale32 said:

Probably a reaction with the fresh paint edge and a little heavy handed. The fresh solvent will lift it.

 

Hth cheers Bevan 

this is what i was thinking, if it was more of a technical issue while airbrushing, since its in the corner, will try with lower psi net time 

 

so i sanded down all the imperfection , ill wash to remove any greases then try again i guess. 

[Woody V]

That’s strange. Crazing like that is commonly found when painting lacquer over enamel but you used all lacquer. 

What thinner are you using? Generic lacquer thinner is a lot “hotter” than thinner designed for models. 

Other than that I got nothing. 

[dmthamade]

7 hours ago, Archer Fine Transfers said:

That’s strange. Crazing like that is commonly found when painting lacquer over enamel but you used all lacquer. 

What thinner are you using? Generic lacquer thinner is a lot “hotter” than thinner designed for models. 

Other than that I got nothing. 

 

Have to agree with the hot lacquer thinner as cause. Have had this happen a long time ago using a bulk lacquer thinner. Switched to the manufacturers thinner or Mr. Color Leveling thinner and all problems went away.

 

Don

[Neo]

10 hours ago, Archer Fine Transfers said:

That’s strange. Crazing like that is commonly found when painting lacquer over enamel but you used all lacquer. 

What thinner are you using? Generic lacquer thinner is a lot “hotter” than thinner designed for models. 

Other than that I got nothing. 

Using mr color leveling thinner

[quang]

I don’t think thinner is the issue. 
I’m using mostly hardware store generic lacquer thinner and never have problem with the paints I use : Mr Surfacer 1200, Gunze Mr Color, Tamiya LP, AK Real Color, Hataka Orange line.

I also have Gunze Mr Color Levelling thinner I bought years ago that I use from time to time just out of curiosity. I don’t see any difference with the generic variety.

Of course like always YMMV. 
 

Looking back at your original post, I’d wonder why the crazing always happens at the very same spot. 
One other thing is that it appears from the first photo that the paints (and primer) were applied in rather thick coats.
Maybe you should try with thinner, more diluted coats and leaving more time (15 minutes?) between coats.

Hope this helps.

Cheers,

Quang

Edited May 25, 2022 by quang

[Neo]

5 hours ago, quang said:

I don’t think thinner is the issue. 
I’m using mostly hardware store generic lacquer thinner and never have problem with the paints I use : Mr Surfacer 1200, Gunze Mr Color, Tamiya LP, AK Real Color, Hataka Orange line.

I also have Gunze Mr Color Levelling thinner I bought years ago that I use from time to time just out of curiosity. I don’t see any difference with the generic variety.

Of course like always YMMV. 
 

Looking back at your original post, I’d wonder why the crazing always happens at the very same spot. 
One other thing is that it appears from the first photo that the paints (and primer) were applied in rather thick coats.
Maybe you should try with thinner, more diluted coats and leaving more time (15 minutes?) between coats.

Hope this helps.

Cheers,

Quang

Thanks for the feedback, 

 

the primer was applied days before, then the grey, using the black basing technique. there was probably a day between the gray and the green. 

 

this pic was after i had done 4000 & 6000 sanding to remove small flaws in the paint, this pass was done with more then usual thinner, since i just wanted to lightly cover the sand marks.

 

From all the  comments i think 3 things are in my mind,

1 there was finger grease, and since there is a similar mark on the other side it kinda fits my pinch hold, 

2 i think i went with too thinned paint that cause excess of thinner on the underlying coats.

3 i think my PSI is to high when im hitting the bottom joint (tape to green) that's causing subpar finish on the edge (hence sanding all the way back to the rear cockpit) 

 

Ive prep the surfaces and going to reapply prime, grey green and see it i succeed this time.

 

thank you all for the help and comments its really appreciated. 

 

Ill post my results soon!