problems getting paint to stick when using mask

Ok.. its me again..Amatuer airbrusher..

I am having trouble getting paint to not peel up when using masking tape or liquid mask. I have been painting using Tamiya Acrylics thinned with Windex. Applied with a Paasche single action airbrush. I washed the plastic with warm soapy water first and rinsed it well. I sprayed multiple thin coats of Olive Drab on one occasion and used Buff (light tan) on another. I also tried a first coat of Model Master Grey Primer and then a base coat of Buff and had the same result. After waiting a day for it to dry and masking with either liquid mask or that thin plastic masking tape they sell at the hobby store. It would peel up paint when I removed the mask.

Do you spray it with something after the base coat to prevent this from happening?

Is there a difference in "Primer" then regular light grey paint?

If so what primers do you use?

What do you use to mask that will not remove paint?

THANKS for any help..

Jeff

Reply to
Jeff
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I've had the same trouble with MM acrylics, and I wash and prime also (used MM grey primer, light grey, neutral grey, etc.). Use Tamiya masking tape too. I switched to PollyScale a few months ago and the problem mostly disappeared. I'm currently using Tamiya acrylics (very nice) but have yet to mask so I can't comment.

Cheers,

David.

Reply to
David E. Young

Is your base coat an enamel or laquer primer, or an acrylic? Acrylics aren't good primers, you need a primer that will bite into the surface, and acrylics aren't "Hot" enough to do it.

(Note: this applies to acrylics such as Tamiya, Pollyscale, etc., not acrylic laquers such as automotive paints)

You can use light gray paint, but some specific primers have a "hotter" solvent. Your preparation routine looks ok, what I'd do would be to use an enamel base coat, either a flat light gray or flat white, let it cure a day, then spray the acrylics over it.

I use regular hardware store masking tape, but I use enamels thinned with laquer thinner almost exclusively. The trick is to get the tape up as soon as possible, once the paint has dried, remove the tape, with flat enamels, I pull the tape up in 5 minutes or so.

Ken

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Reply to
Ken

The difference, probably, is that I use acrylics exclusively, priming included. Enamels are simply not an option for me.

I've read PollyScale adheres very well, so that's probably why I've had little trouble masking over them. I'll soon see how Tamiya acrylics behave.

David.

Reply to
David E. Young

What % of windex to paint do you use? I been using water or this formula of retarder, thinner and water that works but never tried windex.

I had this problem once. What I do is when I need to mask something I take the tape and put it on an clean surface. I have used it on my jeans but sometimes it pulls up blue link from them but basically I try to get the tape to lose some of it stickiness. Then put it on the model and it doesn't pull up the paint below.

I have been told Testers sells an masking tape that is less sticky than regular masking tape. It runs 4 to $5 a roll though. I haven't tried it. I'll stay with my cheap tape and a clean surface.

Rikk

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Reply to
Rikk30

Well, you have a number of leads to explore: a) Windex wasn't designed to thin acrylics and its components may interact in an undesirable way with the pigment carriers. Try using Tamiya's thinner. b) the soap you use might contain skin-softening oils or some other cosmetic stuff that resists washing and prevents the paint from sticking correctly. Try using dish-washing detergents or rinse the parts in ethanol. c) the adhesive on the masking tape is too strong. I've found that Tamiya's masking tape is just about right, but it's quite expensive. You might try sticking your masking tape on a surface such as a piece of cardboard first, to make it lose some of its tackiness. Some people use post-it notes, but these aren't well suited to masking curves. d) you don't wait long enough for the coats of paint to dry. Acrylics are paints that dry (evaporation of the solvent) and cure (polymerization of the acrylic resin). The drying is almost instantaneous, but the curing process can take anywhere between 3 and 12 hours, depending on the paint and the ambient temperature. An inadequate thinner can seriously affect the curing times.

Reply to
[SM04]Serge D. Grun

I use acrylics most of the time. The advice so far has been good. A few additional comments:

Spraying acrylics over NMF (specifically SNJ in my case): The most obvious situation are anti-glare panels. The adhesion of the acrylic to the very smooth SNJ is poor, and there is a tendency for bits of the paint to stick to the mask laterally and come off with it, roughing the paint edge on the anti-glare panel. In this case, I very gently run the tip of a brand-new X Acto #17 blade along the edge of the mask before removing. Problem solved. Presumably the same thing can be done as a fail-safe with any masking situation, though it is very easy to apply too much pressure and actually cut into the finish.

I rarely prime with a true primer. When I do prime, it is only to eliminate underlying color disparties (red plastic, plastic and resin of different colors, etc.), or to prep for application of large areas of red or yellow.) In such cases, I use Tamiya white. I also prep models for painting with isopropanol rather than dishwashing soap, because I am assured of complete evaporation without residue, and I also don't risk water getting inside the model and lingering.

Mark Schynert

Reply to
Mark Schynert

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