Title
Tips For Masking Multi-Colored Interiors

Author
JoeB

Published
Friday, January 18, 2008

If you have ever wanted to paint an interior for your model more than one color, you may have run into some problems. Due to the complexity of some interior designs, masking certain parts can be difficult. This tutorial aims to alleviate many of those problems so you can have a realistic looking interior without paint runs, uneven lines, or overspray.

First, you will need to get all of your materials ready. In addition to the tools you'll be using to actually paint the interior, such as an airbrush, compressor, etc. you will need:

1. X-Acto knife and a new No. 11 blade. It is important that the blade is sharp. A dull edge will rip masking tape and create an uneven line.

2. Tamiya masking tape. I have had the best luck with Tamiya tape because it is flexible, thin, slightly transparent, and relatively low-tack. I highly recommend you use Tamiya tape over any other type.

3. A cotton swab and a toothpick. These are used for burnishing the tape so it completely covers and seals the part you're masking.

4. Primer, clear gloss paint, and semi-gloss or flat clear paint. Primer is necessary because without primer, the paint will have nothing to stick to except bare, shiny plastic. When removing masking tape after you are finished painting, tape may lift the paint off of the plastic if the paint is unprimed. Use white primer for colors like tan, yellow, red, orange, blue, green, and white because these paints have relatively transparent pigments in them and can be significantly darkened if using a gray primer. If you are using gray, black, or metallic colors you only need to use gray primer. In addition to primer and the colors you chose for the interior, you will need clear gloss and either clear flat if you're replicating a cloth interior, or semi-gloss clear if you're depicting a leather or vinyl interior.



This is the interior I will be using to demonstrate some of the methods I use when masking. This particular interior is from Tamiya's Toyota Celica kit.



The first step is to wash the parts in a mild detergent solution to remove any oil or contaminants from the plastic. Any oil or mold release compound will prevent primer from sticking to the plastic. Let the parts dry, and then prime. Again, use white primer for light colors, and gray primer for darker colors. I prefer Tamiya primer because it dries smooth and covers well.



After the primer has dried, you can begin spraying color. You'll want to paint the easiest to mask parts first so you don't have to mask the really difficult parts. In this case, I sprayed tan first, and will spray gray later. If your first color is darker than the second color, there will be an extra step coming up later.



After the first color has dried , we can begin masking. Deep recessed areas, like the rear seat, can be difficult to mask. With an area like this, two strips of tape instead of one should be used. One piece of tape will have to be stretched in a way it doesn't want to be stretched, and will not mask well. First, lay the first strip of tape down, then burnish with a cotton swab. When burnishing with the cotton swab, start with the area being masked, moving outward. The red arrows indicate the direction in which you should be burnishing.





After burnishing with the cotton swab, this is how it should look.



The crease between the seat and the rest of the bench still needs to be burnished further, so we know where to cut the tape and so it will seal well. A toothpick works well for this. Just run the toothpick in the groove several times until it is defined enough for you to see it clearly.



Here's what it should look like after burnishing with the toothpick.



Then do the same to the other side.



Next is the backrest. Since this piece isn't as heavily recessed as the other part of the seat, a single piece of tape can be used. Use the same burnishing methods as described before.



Next we'll need to cut the excess off from the tape. Follow the lines you marked when you burnished with the toothpick. Take your time here. Patience really pays off when doing this step. Don't press too hard with the knife; doing so may damage the model. When you have completely cut the excess tape away, carefully remove the unneeded portion.





Oops! I made a mistake on the seat. I accidentally cut inside of the lines. If this happens, just put on more masking tape, burnish, and trim again. Deepening the groove in the plastic with an X-acto knife or a scriber can make it easier to see under the tape if you're having trouble finding it when burnishing.

After all problems have been fixed, it's time to burnish the outside edge of the tape. This is done so paint won't run under the tape when spraying the second color.



Follow the previous steps for the other seat.



Next up are the front seats. Use the same method as we used on the rear seats for all of the seat but the headrests. When we get to the headrests, use a piece of tape long enough so that it will wrap around the back, since the back will be tan as well.



Wrap the tape around the back, and make two slits where the tape would stick to itself if the tape was stuck together.



Peel the tape back off of the back of the headrest, and tuck the tape on the front of the headrest around to the back.



Then fold the tape back over to the back, and fold the "wings" onto the front.





Using the same techniques outlined for the back seat, cut the excess tape off.



On rounded parts like the center console, one piece of tape can be used, but make sure to heavily burnish all creases that appear in the tape. Make sure you don't tear the tape.





The details on the door panels and dash are similar to masking the previous parts. Again, follow the previous application and burnishing techniques.



Here are all of the parts masked. This took me an hour or so to do, don't be discouraged if it takes you longer.



Before moving on, check that all of the tape has been burnished well, and fix any problems that you may have missed. After fixing any problems, it's time to spray a coat or two of clear gloss. The reason for spraying clear gloss is to seal the tape so the second color won't bleed under the tape. Gloss is used because it is slightly thicker than flat or semi-gloss and seals the tape more easily. If you are spraying a lighter color over the first color, you may want to spray a small amount of primer to make sure the darker color doesn't bleed through the lighter one. This is especially important if spraying a light paint over dark colors or red. I will spray dark gray over the tan, so I'm skipping this step.



After the clear has dried, it's time to spray the second color. It is important to spray 2-3 light coats instead of one heavy coat. Even though the clear sealed the tape, spraying paint on too thick can still cause bleeding.



When the second color has dried for an hour or two, you can remove the mask. If you wait too long to remove the tape, the tape can actually begin to chemically bond with the paint, pulling paint and leaving a nasty residue after you've removed the tape. This usually only happens if you leave the tape on for weeks or months, but I remove the tape as soon as possible just to make sure I don't have any problems.



If you still managed to get paint under the tape, it's now time to do some touch-up with a brush. After any touch-ups, spray the entire interior with flat clear or semi-gloss clear to assure an even sheen.

Final assembly and detail painting of the interior can begin.



If you wish, this tutorial can be modified to do any amount of colors you would like. Each interior will require some amount of planning depending on what should be painted first, what part should be masked, etc. but nearly anything should be possible with a little thought. If you totally destroy a paint job, don't be afraid to strip it and try again.

I hope this tutorial has been helpful and insightful. If anything is vague or needs further explaining, feel free to send me site mail.