A tricky masking job

[Guest]

The following two pics show the need for a tricky masking job:

[ATTACH]89023.IPB[/ATTACH]


[ATTACH]89027.IPB[/ATTACH]


It is a wheel cover, scale 1/16. (In my case, the red will be green.)

For a good smooth gloss paint job (as for the rest of the model) I plan to airbrush with Tamiya Synthetic Lacquer TS14 and TS43 (a spray-can product that I have used for the rest of the model). The problem is, how to mask between the two colours?

Ideas:

A:

1. Mask off all the green except for a 2 mm band touching the interface. This would be done simply with separate strips of Tamiya tape with little effort to make the 2 mm band smoothly round;

2. Airbrush the black up to and over the interface, inevitably on to the 2 mm band;

3. Mask off the black part (but not the 2 mm band). To get a smooth round edge great care would be needed if using Tamiya tape. Or I could use one of those rubbery masking fluids (if they don't pull up paint, but lacquer is pretty hard);

4. Airbrush all the green part

The problem here would be making the round edge in step 4 smooth either with the tape or the fluid.

B: Replace "black" for "green" and Vice versa. Would this be better in some way?

C: If I can't get a sharp non-wavy edge between the two colours (pretty important), airbrush the whole thing black.

D: I've just thought. Perhaps, to get a sharp non-wavy edge, I could use a sausage of White Tack on the black, touching the interface, and fill in with tape over the rest of the black.

E: Or, again to get a sharp non-wavy edge, I have some 1 mm diameter polystyrene rod which I could fix in a circle following hard up to the interface, following the change of surface there, and fill in the rest of the black with tape. But would the rod stay put?

It is a pity that Revell did not make the cover in two parts-easy enough to do.

Any ideas please?

[yak face]

Have you got a compass cutter Steve? You could just measure the diameter then cut a circle out of some suitably wide masking tape (you can get 2" masking tape ) then spray the green , mask with the circle and do the black. John sells them in the Scale models shop if you havent got one , hope this helps cheers Tony

[stona]

I'm with Tony.

Cheers

Steve

[john i am]

Throw away the masking tape or use it for something else Steve. Spray you tyre cover black trying not to get to much over spray on the wheel but as you are using dark green it shouldn't be a problem anyways.then using a circle stencil from whs find the correct circle to match your wheel and spray away(mist coats only don't flood the area) I have been using this method for a while and it works very well for me hope this is helpful cheers John [ATTACH]89048.IPB[/ATTACH]

[Ian M]

I would go for the masking tape and a circle cutter. Use the disk to mask the rim then the hole from where the disk came to mask the cover.

The circle stencil John tells of is another great idea.

Ian M

[Guest]

Success! I bought the compass cutter from John’s shop and it worked a treat. I had to practice. I find that with all compasses, moving the pencil (blade in this case) around the pivot point and round the back and round to the starting point nearly always causes the pivot point to come out of its hole and the cutter wanders away and spoils the smoothness of the curve.

To avoid that I stuck the Tamiya tape on to a base consisting of a small piece of plastic (the side of a Benecol box). The compass was kept still (except when actually cutting clockwise) and after each time a cut was made the plastic and therefore the tape was moved round in the opposite direction (that is, anticlockwise). Each cut covered about 45 degrees before the plastic was rotated again, the blade and the point being easily kept in position on the tape. This made it very easy to keep control of the compasses. (First photo):

[ATTACH]89385.IPB[/ATTACH]


I masked the hub with a disk of tape cut with the compasses plus a narrow (straight) strip of tape to cover the internal vertical edge, ready for the black lacquer:

[ATTACH]89386.IPB[/ATTACH]


The part was then sprayed in black and the masking tape removed. Next came the tricky part. Using the compasses, I cut some tape to mask the black up to but not including the raised ring on the wheel. At first, I planned to use a big piece of tape with a circular hole, applied in one piece and carried down the outside rounded edge of the part, creasing as necessary. However, I found it impossible to cut the hole to the sub-millimetre accuracy required. The compasses don’t have a screw adjustment to give so small an adjustment. Also, such a large piece of tape became unwieldy and inevitably did not fit all the way round without being stretched, (and tape is not very stretchable) or creasing it, to get a good fit. Another approach was needed.

I cut a narrow ring of tape with the compasses as accurately as possible and manually fitted it around the black part of the wheel right up to the external vertical edge of the raised ring of hub. This worked very well, was quick and was highly accurate because of the manual tweaking every three millimetres or so as I went along. This photo shows the result with a small area unmasked to show the ring of tape:

[ATTACH]89387.IPB[/ATTACH]


A thin line of Pledge Klear was then run twice along the edge of the tape where it met the external vertical edge of the raised ring of hub ( temporarily black) to minimise bleeding. Here is the final result after the green was sprayed:

[ATTACH]89388.IPB[/ATTACH]


It looks as good as I hoped. In fact, the external vertical edge of the raised ring of hub (next to the black) has successfully been coated in green.

Thanks for mentioning the compass cutter.

[john i am]

Nice one Steve great result