Looking for tips on using Scalecoat 2 paint
#1
So, I've been working on some F&C milk cars as mentioned in another thread under this "Tips and Tricks" part of the forum. I've gotten one done to the point where I've applied a few coats of Scalecoat 2 Pullman Green (twice Curse ) The issue I am having is the paint is going on grainy (in some places). So, I'm looking for some advice on what might be causing the paint to do that and some tips to correct it. Let me set up how I was applying the paint. I mixed the paint 60/40, 60 Scalecoat thinner/40 paint, in that range, more to the 60% side. Reefer was primed with Tamiya Fine Scale primer. Air brush set about 20-25 psi. My paint booth is now in the garage, my first attempt to paint the reefer was during the week and it was not as humid as it was over the weekend here in NJ. When I painted it during the week, I did multiple coats over a 4 day period. Toward the end of laying on the coats I noticed the graininess. I stripped the paint on Saturday, washed in mild soap and air dried, primed again, tested application on a styrene sheet and found it to be smooth, then applied a few coats to the reefer every 3 to 4 hours. Found more graininess, but not as bad as it was the first time. The bottom of the reefer was the way I would expect to see Scalecoat to look, the sides not so much. Top of the reefer seems OK, too, this time. This is the first time I am using Scalecoat 2 paint, I've used Scalecoat 1 on other projects and not had this problem.

Some thoughts or observations I think happened are: 1. the paint was drying as it was being applied, because I was holding the airbrush to far away from the reefer in some spots? And if this is the case, how far away should the air brush be from project being painted. 2. Bad mix with thinner to paint ratio? 3. Humidity? 4. PSI is off. 5. Should I try and paint the reefer in one setting instead of multiple coats?

And I was wondering if, after decals are applied, would a coat of flat sealer remove the graininess and even everything out?

Here are some pictures of what is going on:

[Image: IMG_0501_zps1xgt0vi5.jpg]

[Image: IMG_0499_zps2avh4can.jpg]

[Image: IMG_0504_zpsiexvjj0s.jpg]

[Image: IMG_0500_zpsfnoyojau.jpg]

Thx,

Mark (Ugh)
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#2
I use Scalecoat I on plastic without any issues, and thin it about 40% with lacquer thinner. Scalecoat II is comprised of pretty-much the same chemicals, but in different proportions. My guess is that you've used too much thinner. The first time I used Scalecoat, many years ago, I was concerned by the paint's apparently thick consistency in the bottle, and was tempted to thin it more generously than I would have done with, f'rinstance, Floquil. I didn't though, and it sprayed very nicely, yielding a very nice and extremely durable finish on plastic.

Scalecoat also notes that no primer is required, so the paint may be reacting with the primer. As for multiple coats, I prefer to apply successive light coats with Scalecoat I: paint the whole car, then, before the applied paint can dry, paint it with another light coat in the same sequence as before. Depending on the colour you're using and the density of the application, I'd guess that one to three coats applied in this manner would be sufficient for complete and even coverage. I don't know about Scalecoat II, but I let Scalecoat I dry for several days before handling it - it may be dry to the touch much more quickly, but that's certainly not cured. There's a very good chance that your subsequent delayed applications are reacting with the not-wet-but-not-yet-cured paint.

Wayne
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#3
I want to add something I was taught many years ago at a paint clinic run by PPG. It pertains to automotive paints From the 60's and 70's but I think it will also apply to most model paints. You want to start with a light coat and let the solvents flash out. after that happens you can apply a second heavier coat because the first coat will absorb some of the solvents and help keep the paint from running. if a third coat is needed it can be even heavier, just be sure the paint is allowed to flash well between coats. each coat will bond together and it will just be one coat when finished, and as Wayne said it takes several days for the paint to cure.
I saw the second coat lift the first coat on a car I was painting when it was very hot and I waited too long for the second coat so timing has a lot of bearing on the job.
Charlie
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#4
Doc, I'm sure you've answered this before, but what led you to use SC1 and lacquer thinner on plastic instead of SC2 and SC2 thinner? And is that the same combination you use when painting wood and metal? Just curious?

Mark
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#5
Mark, the first time I used Scalecoat, (pre-I and -II) I was a regular user of Floquil, and I had always used lacquer thinner with that. It just seemed natural to carry on as usual. I also use lacquer thinner with SMP's Accupaint and some Humbrol stuff, along with Testors Dullcote and Glosscote.
In those days, there was only one hobbyshop, within reasonable driving distance, that carried Scalecoat, and I don't ever recall seeing Scalecoat-specific thinner there. I'm not sure, but perhaps someone there suggested lacquer thinner, which, to one using it for other paints, sounded totally reasonable. I certainly does work well.
And no matter what type of paint I'm using, whether with brush or airbrush, clean-up is with lacquer thinner. Until a couple of years ago, when the formula for lacquer thinner was changed, it was also my solvent-type cement-of-choice,. The revised version still works for paint thinning and clean-up, but is useless as a solvent-type cement for styrene.

Wayne
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#6
Well, I'm happier with the results I have finally gotten to, the third time around. I watched some "How to" videos on air-brushing on Youtube and found one 6 part series that was very good Thumbsup . I think part of my problem was I was holding the air brush to far away. I was more in the range for a spray can away from the reefer. So, I got the air brush closer and turned the air pressure up a tad.

Here are my results:
[Image: IMG_0525_zpsikhnfmwv.jpg]
[Image: IMG_0526_zpsnql3nd3m.jpg]

[Image: IMG_0528_zpsf5cgaxhb.jpg]
[Image: IMG_0529_zpsa0ujnxle.jpg]

Thanks for sharing your suggestions.
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#7
That's definitely an improvement...looks great! Thumbsup Thumbsup

Wayne
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