Painting/priming over a Red or Yellow molded body?

[RickRollerLT1]

I have bodies that are molded in red (like the Monogram '85 Fiero GT and the Revell '93 Firebird Trans Am SnapTite) and would like to paint them a bright color like White or Light Blue. Yes, I prime my bodies (K-Mart Quick and Easy Gray Primer, almost flawless results otherwise) and yada yada, but I have experienced in the past the red molded color spectrum (like dark red, pink, etc) bleeds through turning giving a pinkish hue (bleed through).

This also occurs with Yellow and bright Greens too, also giving a yellowish bleedthrough. I have done many topic searches and tried many tricks, including one of spraying silver or flat brown as a neutral color on the body then primer and the color, bleedthrough would still occur at the silver or the even the gray primer coat. I even tried the Future trick, as not only it still bleed through the primer but it reacted with the Future coat that fully dried for 3 days, causing severe wrinkling. I even got a can of Duplicolor Automotive Primer/Sealer and while that seemed to do the trick, it caused such severe crazing on the Firebird body that sanding and additional coats made it worse (It should strip off, hopefully).

Are there any proven ways to overcome this paintbump? At worst, I could paint the other one red or black and use a spare white molded Firebird/TA body for my project. But when I do future projects molded in red and yellow and want to paint them bright colors without bleedthrough hues, then without spare white molded bodies I'd be SOL unless its gonna be black or matching the molded color.

[StevenGuthmiller]

You may be closer than you think.

I've settled on a priming technique that works pretty well for me & I've never had this "bleed through" problem that everyone talks about.

I use primarily Duplicolor sandable primer over a coat of Testors lacquer primer.

The Testors covers better than the Duplicolor, but the Duplicolor gives a superior barrier & a smoother finish.

You're correct, the Duplicolor primers will craze the plastic if laid on too heavy.

Light coats are your best friend.

I start with a coat or two of Testors gray primer to cover the body well, & then I use up to 5 coats of Duplicolor.

I start with light "mist" coats & get progressively heavier with each successive coat.

I also let them cure, or "gas out" for an hour or so between coats.

In a nutshell, more primer is your friend.

I've never had any bleed as long as there was plenty of primer involved.

 

Steve

 

 

I don't have a before pic, but this '59 Edsel started the same color as the above '59 Ford.

 

 

 

Edited May 25, 2016 by StevenGuthmiller

[Harry Joy]

I use Tamiya Fine primer and generally do not have issues with bleed through. It has happened, but only in cases where I applied primer, then realized I missed something needing sanding. When I sand the primer and the offending mark, that spot always seems to bleed through even subsequent applications of the primer.

It took a bit, but I finally figured out that silver paints do a good job of sealing color parts. If I have to sand a part when I'm into the painting process already, I'll hit it with some Tamiya Silver Leaf spray. Seems to do the trick.

[RickRollerLT1]

 

You're correct, the Duplicolor primers will craze the plastic if laid on too heavy.

Light coats are your best friend.

I do everything with light coats at first then go heavier. But in this case, because the crazing was starting after the initial light spray, I knew more coats wouldn't cover it (no pun intended). After letting it dry for 2 days, I sanded the 1st Duplicolor coat then applied another coat and the crazing still happened! I figured the crazing would go away once tie color is on, so I let it dry fully, then sanded AGAIN and tried Duplicolor Gloss white (with light coats), gave me extreme wrinkling (or what looked like major orange peel) but hardly any red bleed. Thankfully, the DP stripped off because I got to it quickly before the coats fully cured and etched into the body. So attempt 2: Being I have a can of Tamiya Fine Primer I got when it was cheaper a few years ago, I also tried the Tamiya Primer suggestion the 2nd poster brought up. The 1st coat bleed like the standard Q&E primer I was using, so I knew that wouldn't go well ether. I will also try Rustoluem Automotive primer/sealer, as that's enamel/lacquer like the K-mart stuff so I shouldn't get heavy crazing like the Duplicolor. I'm a little scared about putting Duplicoat primer over Testors Lacquers Primer. The latter I believe are actually Enamel-lacquers, and being Duplicolor is full Lacquer, I would smell a bad reaction happening. But if it works for you and it is proven, I may give it a shot (hopefully is isn't more money wasted... like I have a wad of cash burning in my pocket right now!). 

Could it be this dammed plastic they were using back then has some crazy dye in it? Lucky for you, Yellow isn't as chaotic as red molded bodies and most metallic colors cover up its bleedthrough, so those are easier for you. As I said before, this is not extremely critical as its a test for future projects, and being I have another white molded body for my White 2JZ project the red molded body will be used to rebuild my red 2JZ powered Firebird from 2009.

Edited May 25, 2016 by RickRollerLT1

[RickRollerLT1]

It took a bit, but I finally figured out that silver paints do a good job of sealing color parts. If I have to sand a part when I'm into the painting process already, I'll hit it with some Tamiya Silver Leaf spray. Seems to do the trick.

I tried that too as I mentioned in the 1st post (not Tamiya). Still had the bleed through and I tried everything!  I will be trying the Rustoluem Primer/Sealer next.

Edited May 25, 2016 by RickRollerLT1

[Harry Joy]

I tried that too as I mentioned in the 1st post, still had the bleed through and I tried everything!

Are you using only automotive paints?

[RickRollerLT1]

Normally I mix and match various paint brands and get very good results. I would first prime with the cheap Quick and Easy primer, then to cover the gray for good measure I lay down Wal-mart Colorplace flat white for bright glossy colors or flat black for glossy blacks or metallics. For the bright colors, the final coats over the flat white will ether be Colorplace gloss white, red, blue, or sometimes the Tamiya/Rustoluem/Valspar/Krylon gloss variety for different colors like yellows, etc. On top of the flat black coat, its gloss black or a Rustoluem silver base coat to put Tamiya or Krylon X metals over. No reactions or ill effects at all with this method.

But in this instance I kept paint brands the same for safety measures because I was told "you can't go wrong sticking with the same brands". Well, everything's going wrong here!  I tried the silver trick again, this time with Duplicolors on a spare red piece and the same thing happened! I will try the Tamiya trick too but I doubt that would work ether, since the same thing happened with my standard paint methods.

Edited May 25, 2016 by RickRollerLT1

[StevenGuthmiller]

I'm a little scared about putting Duplicoat primer over Testors Lacquers Primer. The latter I believe are actually Enamel-lacquers, and being Duplicolor is full Lacquer, I would smell a bad reaction happening. But if it works for you and it is proven, I may give it a shot (hopefully is isn't more money wasted... like I have a wad of cash burning in my pocket right now!).

If it's something you're not comfortable with, I wouldn't do it.

All I can tell you is that I have probably 30 built kits sitting on my shelf all done the same way, & they all worked fine.

I did have some issues in the past with spraying automotive lacquers over Testors primers directly, but since I started using the Duplicolor over it, I've had good luck.

Mind you, I only use the Testors primer to get good coverage to start.

The Duplicolor sandable primers are quite thin & do not cover very well, but they do provide a good smooth barrier for the lacquer paints that I use.

If you have another primer that covers well, (especially with colored plastic) & acts as a good sealer to any hot paint that you may use, by all means, I would use it.

But if you're having crazing issues, obviously, something needs to be done differently.

I build a lot of vintage kits & rarely have any major problems with crazing, but I am of the understanding that the newer kit plastic is much more prone to that particular issue than the old kits.

You'll most likely have to just keep experimenting until you find a system that works for you.

Every guy on this forum probably has their own method & I'll guarantee you, they're all born of experimentation.

 

Steve

[Harry Joy]

All I can suggest is trying a non-automotive paint as your primer coat. Tamiya, Testors, what have you, just something not so hot. The auto paints go well with those.

[High octane]

I've had great success with colored plastic bodies by painting them with Tamiya's Silver Leaf, then Tamiya's White Primer, and then my color coats and clears.

[dshue76]

I use water based acrylics and just use a light grey for the primer coat on dark molded colors. Right now I'm working on an AMT Chevy Rescue Van that was molded in red and my method covered excellent. The final color is a medium blue. 

I could have gone with any color and there is no way the red would show through. 

[Mike_G]

I used PlastiKote white sandable primer on my '53 Victoria that was molded in red and didn't get any bleed-through. In fact, the top is just primer that I wetsanded and clearcoated.

[RickRollerLT1]

Thanks guys! Like I said, I looked up every single search about bleedthrough and just tried about everything in the book. 

For the newer plastics bit, yeah I noticed that when I used to use Krylon Fusion during my early days. It took a while to find a good cheap primer to handle that plastic type, but then I found the K-mart primer I use doesn't craze it, so that became my standard primer as its equal to Tamiya Fine Primer and more efficient at cost.  Its not just this generation of kits with this phenomenon, as there's a lot of older kits (80s Revell Ciji and some retail sold MPC kits like the KITT) with plastic so "thin" in some spots, you could put finger underneath and it would show through! My Firebird's plastic is kinda thin being a SnapTite meant for retail (there was a story about how model manufactures used better plastic for the kits sold at hobby shops but lesser grade for the big boxes) , so that may be why the Duplicolor crazed it. 

I will be trying Rustoluem automotive primer/sealer as its enamel/lacquer (same type as the K-mart stuff I use), so crazing may not be as much of an issue unlike the Duplicolor.

[martinfan5]

I am going to second what Nick said, silver works good.

the only time I really worry about any bleed through is if I want to do a white paint job on a molded in color body, thats when I will start with a silver base coat.   But for darker colors, I never worry about it, just start with primer and make sure the coverage is good.

Edited May 28, 2016 by martinfan5

[Roncla]

 When I have run in to bleeding problems and plastics sensitive to solvents or where I have done bodywork I always use Barcoat Isolator or BIN Sealer.

I use auto paints which have hot solvents so I need a reliable effective barrier.

http://www.u-pol.co.uk/documents/datasheets/tds/BAR-TDS-EN.pdf

http://www.zinsseruk.com/product/b-i-n/

I have found both to be equally effective with the BIN being white and the Barcoat beige in colour.

Both of these  are shellac based and I use  methylated spirits to wash up my airbrush.

 

[Snake45]

Could it be this dammed plastic they were using back then has some crazy dye in it? Lucky for you, Yellow isn't as chaotic as red molded bodies and most metallic colors cover up its bleedthrough, so those are easier for you. As I said before, this is not extremely critical as its a test for future projects, and being I have another white molded body for my White 2JZ project the red molded body will be used to rebuild my red 2JZ powered Firebird from 2009.

No. As I've explained on here many times, no color or pigment actually "bleeds" or "leaches" out of the plastic. It doesn't happen. If you have a color "bleeding" through, it's because your paint isn't opaque enough. It's just that simple.