I managed to stuff up another simple paint job on my K-25 Alpha... Nothing complicated... just painting the black stripe and fin for the 1970s paint scheme. I had painted the entire rocket white, and let it dry for a week. Then I masked off the desired area with premium (green) masking tape, burnished all the edges very carfully, and shot 2 coats of the gloss black.

When I went to remove the masking tape, the paint along the edges lifted and came with the tape leaving a ratty looking ragged line. My guess is since I was painting over a gloss surface that the black didn't get a good enough hold.

I have to admit, spray can painting baffles me. When I do a plastic models, I typically shoot Tamiya flat acrylics through a double action airbrush and never have any trouble even with the most complicated paint schemes. I don't even consider that my paint might attack the primer, or that removing masking material will ruin the paint edge.

Don

That may be a factor. I usually, but not always, mask, sand, re-mask, then paint. Although sometimes I just paint over the cured, gloss finish without sanding.

It sounds like, in your case, you let the paint dry before you removed the mask. I learned, working in a paint shop, to remove the mask while the paint is wet, so that's what I always do.

Sometimes, it takes four hands, some painting jigs, cleverness and holding your tongue just right to get the tape off without marring the wet paint, but I don't get any flaking that way.

Doug

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YORF member #11

I agree here.
I seem to get a better mask line if I remove the tape before the paint has had fully dried.

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Hans "Chris" Michielssen
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"Nose cones roll, be careful with that."
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^^^I've found this to be true.

But to the original problem; shooting it two times may have contributed as well. If you do that, you are for sure going to get a "lip" on the edge of the masking—even in a best case scenario. You'd have to sand, at least the edges, of the masked paint to get a clean release and then clear coat it. Tamiya paints (I think) don't have near the viscosity of typical spray can enamel.

I'm still screwing up rattle can jobs myself. The small Testor's cans of spray paint seem be be a bit thinner and have a better spray for smaller jobs, but then, of course, the little cans cost as much or sometimes more than a standard can of Rustoleum.

That brings up good point.

Don, How long between coats of black did you wait?

FWIW, when I apply two coats of any color, they're just a few minutes apart.
...
My experiece in painting has been that the first coat functions as a "tack" coat. I just put on a thin application, with poor coverage, then wait 10-15 minutes. After that, I can put down a heavier second coat with little fear of runs. I then wait another 10-15 minutes, and apply a 3rd coat, if necessary, if there are still some thin or dry-looking spots.

Doug

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YORF member #11

Well I think the point here is that Tamiya paints are acrylic based, and so are going to be fairly inert with respect to their interaction with tape adhesive.

As mentioned, I don't think it's a viscosity issue, I'm thinking its a solvent/tape adhesive interaction issue.

Just my best guess;

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John
YORF #003
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Some brand paints are just plain easier to work with than others......

Rustoleum is fine howver i really like using Krylon and Testors paints.... Krylon is just about the most user friendly paint out there..... I first sand up the body and fins with 400 paper. then spray primer, set aside... the next day, I will sand the primer again with 400, inspect, shoot with primer if needed..... Once Im happy that the grain is filled in on the fins and the spirals are filled in I sand again the body and fins real good with 400-600 paper.

I'll use my Estes patriot M104 as an example.... I first shot down the base white gloss coat. set aside.... the next day I used regular masking tape and masked off the fins and shot them down with gloss red.....set aside... the next day I masked off the end of the body and shot that down with gloss yellow.... set aside.... the next day I trimmed out some glossy red monocoat trim sheet and slapped that on the end of the body tube by the nose cone.... added decals...set aside... finally I shot the whole thing down with Model masters top coat clear enamel and here it is....

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I did attempt to remove the mask while the paint was wet. I say attempt because I had most of the rocket masked off with blue painter's tape and it took awhile to get down to the green tape that was my actual masking line. I think the paint cured somewhat during the 5-10 min it took to get the tape off. I suppose I could reverse the order of my masking such that the mask line comes off first.



I know I said two coats but really it was one since they were only about a minute apart.


Actually it is Rustoleum. I've been using their Ultra-Coat 2X. It's been working quite well for me but this is the first time I've tried to mask anything.

What I do here is lay down the line tape (usually the vinyl kind that doesn't wick under). This is the tape that forms the paint line. Then I apply the bulk mask alongside that, but leaving a gap. Then I apply masking tape over the gap.

That way, after spraying, all I need to remove is the tape over the gap, then the tape along the paint line. I can then leave the bulk mask in place over night if necessary since it's not in contact with the wet line.

Doug

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YORF member #11

That is an awsome thing to know. This is the kind of stuff that makes this forum worth reading. And it makes perfect sense. The wet paint along the edge will just pool back where the tape line was. Thanks again. Chief nukemmcssret