Model Railroading > Airbrushing help with masking for a hard edge

I want to add a second color to a plastic model with my airbrush but I don't want the soft edge that an airbrush is limited to. I'm trying to figure out what a good 'mask' might be to get a hard edge.

Could it be as simple as a piece of Scotch tape or is there something better out there that i should try? 

What I've read is to use tamalya tape as it has the best ability to get into the grooves and then hit it with either a clear gloss or base color to seal the edge before applying the second color.

Everyone has their favorite tape but I use 3M Blue painters tape.
On a clean piece of glass, stick the tape down and use a steel straight edge and a fresh razor blade and cut a fresh edge on the tape and use that edge to mask your hard line.
When you are painting the line, don't shoot into the line, shoot at a 90 degree and and work out from the edge.
And, as usual, use light coats and not 1 heavy coat 

BNModeler Wrote:
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> Everyone has their favorite tape but I use 3M Blue
> painters tape.
> On a clean piece of glass, stick the tape down and
> use a steel straight edge and a fresh razor blade
> and cut a fresh edge on the tape and use that edge
> to mask your hard line.
> When you are painting the line, don't shoot into
> the line, shoot at a 90 degree and and work out
> from the edge.
> And, as usual, use light coats and not 1 heavy
> coat 

That makes total sense to me.  Thumbs up.

TomG Wrote:
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> What I've read is to use tamalya tape as it has
> the best ability to get into the grooves and then
> hit it with either a clear gloss or base color to
> seal the edge before applying the second color.

I concur Tom
In the old days I used automotive pin striping tape. It's a heavier version of the Tamalya. Once I tried Tamalya, I won't use anything else. Nice sharp edge and pulls off clean and easily on painted areas. I just shoot the next color over the masked area. Scalecoat paint is all I use currently. 

Tamiya tapes, and burnish the edges of the tape down with a wood tooth pick. You can also burnish the tape over hinges and into panel lines.

Tamiya tape. It's made by a model company for modelers. No voodoo required. I long ago tossed my blue tape, green tape, white tape, beige tape, 3m tape, gorilla tape, frog tape, drafting tape. Well, not really tossed. They are fine for house painting, drafting, and so on.

I've been using Washi tape recently and find it works just as well. But, Tamiya for a newbie. One trick is to use Tamiya on the line and blue, green, white, beige tape to fill in.

Lighter Wrote:
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> Tamiya tape. It's made by a model company for
> modelers. No voodoo required. I long ago tossed my
> blue tape, green tape, white tape, beige tape, 3m
> tape, gorilla tape, frog tape, drafting tape.
> Well, not really tossed. They are fine for house
> painting, drafting, and so on.
>
> I've been using Washi tape recently and find it
> works just as well. But, Tamiya for a newbie. One
> trick is to use Tamiya on the line and blue,
> green, white, beige tape to fill in.

Yes, use the Tamiya tape to mask the line and the much cheaper blue tape to fill in.
That Tamiya tape, as nice as it is, is not cheap.

I'm using Frog Tape - the yellow kind ... not quite as sticky as 3M blue tape, and stickier than drafting tape. Burnishes well. Use a steel straight edge to cut your tape to ensure straight lines.
Tamiya is thicker and I find harder to work with.

One trick - to help prevent the new color from getting under the tape (in crevices, etc) paint a quick, light coat of the color being masked over first, and then the new color. 

I use the Frog green multi surface tape.  Better than blue, not quite as good as Tamiya but cheaper.

Again, like others say, the key is to cut a straight edge on glass with a NEW blade.  Then burnish the tape down.  I've also had great luck by airbrushing a light first coat about 12 to 15'" from the model and let dry for about 5 minutes.  This kind of seals the edge of the tape and future heavier/closer/wetter coats won't leach under the edge of the tape.

Mike Stewart
Oakley, CA

No matter what tape you use, after applying the masking tape, respray the base color along the edge of the masking tape and it will seal any little cracks or holes among the details. So the next color can't get into them and will result in a ultra sharp line.

Ted Curphey
Ontario, OR