Maroon plastic bleed through?

[jaymcminn]

Starting the old Monogram Mercedes 540k coupe kit molded in lovely high-gloss maroon plastic. I'm planning on building it in a two-tone dark blue and light grey color scheme. Has anyone built a kit molded in maroon and experienced the bleed through issue you sometimes see with red and orange plastic? I'm not worried about the dark blue, but the light grey has me a little concerned. I usually prime with Tamiya Fine White or Gunze Mr. Surfacer grey and my top coats will be Tamiya TS paints decanted and airbrushed with TS13 clear. 

[gman]

Do you have sprue from the kit you could do some primer/colour tests on? I suspect if the primer doesn't react with the molded colour of the plastic, then the colour coats won't either (provided you aren't using a really "hot" thinner with your airbrushed colour coats, or are spraying really wet coats).

Generally. silver base coats offer some protection from bleed through, so a coat of silver under the light grey may be a good insurance policy if you do get a reaction.

[moparfarmer]

I had a 70 Challenger and maroon bled threw.on white primer..Sprayed with Perfect Match silver the the while and NO bleed threw..Heard that silver stops bleed threw..

 

[Plowboy]

I would do a test on the underside of the hood. You never know when bleed through will strike! I used to not believe in bleed through until I had it happen. I was painting blue over yellow styrene. It didn’t happen with the primer (3 coats), paint (3 coats) or the first coat of clear. It happened on the second coat of clear! The yellow bled right through. Luckily, I was painting a 34 Ford pickup and had only sprayed the grille and bed. I salvaged the paint job by spraying another coat of blue and only one coat of clear.

Primer, paint and clear were all Tamiya. The kit was the Lindberg molded in a high gloss yellow. First kit I ever saw with such shiney styrene. I almost think that was caused the bleed through. No way to know for sure. But, it didn’t happen with the additional coat of paint and clear.  

Edited June 26, 2022 by Plowboy

[gotnitro?]

spray a coat of silver paint over the molded color plastic 1st, then your normal routine it seals the bleed thru

[jaymcminn]

2 hours ago, Plowboy said:

I would do a test on the underside of the hood. You never know when bleed through will strike! I used to not believe in bleed through until I had it happen. I was painting blue over yellow styrene. It didn’t happen with the primer (3 coats), paint (3 coats) or the first coat of clear. It happened on the second coat of clear! The yellow bled right through. Luckily, I was painting a 34 Ford pickup and had only sprayed the grille and bed. I salvaged the paint job by spraying another coat of blue and only one coat of clear.

Primer, paint and clear were all Tamiya. The kit was the Lindberg molded in a high gloss yellow. First kit I ever saw with such shiney styrene. I almost think that was caused the bleed through. No way to know for sure. But, it didn’t happen with the additional coat of paint and clear.  

I think it's the gloss as much as anything else... I actually had bleed through on that same Lindberg '34 molded in yellow. Good idea to test the underside of the hood! I might try the silver paint trick too.

 

[DRIPTROIT 71]

Silver doesn’t stop the bleed through every time if you are using hot paint like Duplicolor lacquer. Like has been said; test first with all the products that you are finishing with. Even if it looks good with your base color or primer, test with all coats. I had red plastic once that couldn’t stop the bleed through at all.

[slusher]

Monogram has that kit molded in silver also. I have only paint red or maroon plastic red due to bleed thru.

I had it red bleed thru six months after the model was finished!

[robdebie]

In previous threads about the plastic color bleeding through, I reported that I read in a paint technology book that the red plastic dyes are notorious for dissolving in paint solvents, and moving into the paint. My conclusion is: use water-based paints or primers. Or at least try it on a sample to see whether it works.

Rob

[Chariots of Fire]

I had bleed through on some Monogram 1/32 Mack kits in both yellow and red versions.  For some reason it did not happen in every case.  So I'm thinking that it has something to do with the composition of the plastic.  I mated two yellow cabs together to form an extended one and half of it bled and the other did not.  Go figger.  Finally tested the underside of a couple of different kit cabs until I had two that did not bleed.

[Dpate]

Mr. Hobby makes a primer called base white that's made basically like there primer, but it's for covering dark plastic.