Simulation - Paint Masks for the Stars & Bars.

Objective of this workshop.

The application process shown in the main instructional workshop is only one way of applying the paint masks.  As I have run out of models to apply paint masks to I am going to run through with a simulation which should serve the purpose of the exercise.

In this workshop I will show an application of a typical USA  Stars & Bars Paint Mask.

1.

The masks

The Stars and Bars came in many designs.  This is the most common design in 2 colours , blue & white.  They are best produced spraying the blue colour first, followed by white.

To do this you really want to be using quality branded paints with high pigment levels to give good coverage with the minimum of paint.

2.

Position the first mask.

Following the sequence order for the masks, the first to be used will be the "A" mask as shown opposite.  This mask will provide the outline for the blue solid colour.  Always take your time positioning the mask on the model to ensure it is perfectly aligned.

Draw reference lines on the mask if needed using a soft fibre tipped pen. For putting marks on the model, use masking tape and a fibre tipped pen.  I don't advise drawing directly onto the model, where it is not going to be over painted.

When you are happy with the position of the mask, it's time to install the application pins (see separate instructions).  To maintain the position of the mask while the registration pins are secured apply a temporary strip of masking tape over the full length of the mask close to the registration pins as shown opposite.

3.

Fixing the the first registration pin

Lift the temporary masking tape from ONE end of the mask.  Remove the silicone paper from the high tack masking tape.  Be sure not to let the tape curl and stick to the back of the mask.

Holding both ends of the masking tape sandwiched between your thumb and fingers, lower the mask to the surface of the model (as shown opposite) taking care to lay the mask down in line with any reference marks you may have used.

Do not allow any slack to build in the mask as this will result in poor alignment of subsequent masks.

4.

Fix the second registration pin.

Repeat the process in (3) above to secure the second registration pin to the model.  It is worth reminding you to make sure there is no slack between the pins.

Warning.  Do not over tension the mask as you lower it to the surface.  The gentlest pull from the first pin already secured will be sufficient to remove any slack.   You will notice in the picture opposite the temporary strip of masking tape next to the first registration pin installed in (3) above has been re-applied to the model surface.  This helps protect the mask on the first registration pin from stretching.  

5.

Remove the temporary masking tape.

Now that both registration pins are located and holding the mask,  you can safely remove the temporary strip of masking tape which is no longer required.

Other sections of masking tape applied to the model used for alignment purposes can also be removed if desired though not necessary.

Lift off the mask and carefully rub down the masking tape around the registration pins to ensure they are fully secured.

6.

Remove the silicone paper

On a flat clean surface lay the mask face down and peel the silicone paper off DO NOT DISPOSE OF!

Avoid touching the mask on the tacky side as much as possible.  If you have to touch the surface, make contact with the outer extremities of the mask as shown opposite.

Reminder  As you are exposing the tacky side of the mask before application, hygiene is extremely important.  Make sure the working area is clean and free from excessive airborne dust particles!

7.

Cut the silicone paper in half.

Move the exposed mask to one side, tacky side up.  Without delay take the silicone paper and with a NEW scalpel blade cut the mask in 2 halves, using the holes of the registration pins as guide lines.  Ensure your ruler is clean!

WARNING  you must use a new blade to be sure the cut will be clean.  A dull blade will create excessive dust which will transfer to the mask reducing the efficiency of the adhesive.

8.

Re-fit the silicone paper strips

With the silicone paper separated return the silicone strips to the paint mask, but position each strip a few millimetres short of the centre line between the registration marks on both sides.

If you look at the picture opposite the mask has an exposed area 5 - 10mm with the registration holes running down the middle.

9.

Re-fit the mask.

Turn the mask over and re-fit the registration marks over the pins.  Rub your finger down the centre so that the exposed mask and application paper takes grip on the surface.

10.

Removing the silicone sheet.

Lift one of the long edges of the mask and peel away the silicone paper. It is important to ensure the mask remains secured at the middle.

11.

Fix the mask down.

Return the mask over the surface and hold the edge a few centimetres above the surface.  Then with the fingers on your other hand begin wiping to and fro, starting from between the registration pins working your way to the outer edge steadily and progressively.

Note:  There is no need for excessive pressure!

12.

Remove second silicone sheet.

Lift the opposite long side up and remove the silicone paper.

13.

Fix the mask down.

Fit the rest of the mask down as in (11) above working slowly from the centre of the mask to the outer edge.

Remember:  There is no need for excessive pressure!

14.

Remove application tape

Now that the mask is down it's time to remove the application tape.  It is best to remove it in sections.  In this example I am tearing the mask from between the registration pins. 

Pull the tape with gentle pressure 180° to the surface as shown opposite.  Do not peel back too fast and continuously look for the mask separating from the tape as you go.  If you see the mask lifting with the application tape, fold it back and rub down the area that is lifting before continuing. 

As with any operation, take your time, remember the mask only has medium tack like the application tape!

15.

Remove remaining tape

Remove the remaining tape as for (14) above.

Take care not to catch the registration pins introducing excessive strain.  This can cause slack in the application pins, which will eventually result in poor alignment of subsequent masks.

16.

Rub down the paint edges.

To ensure a good seal between the mask and the model surface you should gently but firmly rub down the entire mask edge that borders the paint area to ensure the mask seats firmly in position.  You only need to do the first 5mm or so for it to be to be effective.

Use a spoon handle with a rounded face, or alternatively, I know some people use the leading edge of a new propeller.  It does not really matter what you use as long as has NO sharp right angle edges.  You will notice the mask takes on a darker colour as it is firmed down in these areas. 

If your mask has to bridge panel lines (grooves) I suggest running your finger nail down the groove to seat the paint mask.

17.

Before painting

Don't forget to use additional items to protect the rest of your model from over spray.  I use news papers, magazines and medium tack masking tape. As this is a simulation I will not be showing this in the pictures.

One tip.  Notice there is a scrap of balsa on the pin heads.  This just affords them some protection and reduced the risk of snagging the pins (and your skin)

18.

Spraying.

As this is a simulation I will not be spraying any paint.

You should follow all of the paint manufacturers instructions for best results with your paint. The most important factor is to not overload the surface with too much paint otherwise you will encourage some bleeding into the edges where the paint mask sits.  This will create large ridges when the paint dries resulting in an un-natural finish.

Allow sufficient time for the paint to flash off most of the carrier solvent before you add the next pass of paint.  Water based paints can take much longer to flash off due to the low evaporation rate of water.  Typically you will need to apply 3 or more light coats of paint. 

For this simulation I have applied a blue vinyl substitute to give the impression of colour.  Naturally you will have over spray in a real exercise.  - See my workshop!

19.

Remove the mask.

IMPORTANT: Make sure the paint is dry or almost dry before removing the mask. More critical for water based paints as they are prone to lifting if they are not fully cured.

Remove all the supplementary masking material used to protect the model during the spray process first.

Then remove the paint mask carefully.  Do not simply lift from one corner and peel off like a sticking plaster.  Start from one corner or side, cutting into the mask with a sharp knife working your way to the painted edge as you peel back the paint mask.

To avoid snagging the registration pins you can cut into the mask through the registration marks as shown opposite.  Continue to peel the mask back at 180° to the surface following the outline of the painted edge.

Run your mouse pointer over the image for a later view of this process.

20.

Prepare the second "B" mask.

The second mask should be prepared just like the first mask from section (7) onwards.  

Note:  before applying the second mask you may want to use "000" wire wool, or fine wet and dry to remove any lip that may have formed on the edge of the paint.  If you are not familiar with these techniques, please practice on sample material first before you use them on the model!

21.

Fix the mask down.

Fix the mask down and remove the application tape following the same procedure as for the first mask. 

22.

Ready for painting.

Shown opposite the mask is fully applied and the edges have been rubbed down with the rounded corner of a spoon to seal the paint edges.

Re-fix additional masking to protect the rest of the model for overspray!

As for the first colour, follow the manufacturers instructions for paint application.  A light coat of paint with adequate flash off times between coats is the key to a good finish.

23.

Removing the mask.

IMPORTANT: I know I am repeating the earlier warning but it is worthy of a reminder!  Make sure the paint is dry or almost dry before removing the mask.  In particular water based paints are prone to lifting if they are not fully cured.

Remove supplementary masking before removing the paint masks themselves.  Use the same procedure as described previously.

24.

And there you have it!

The registration pins have been removed and the insignia is complete.

You may want to rub down the lip of paint at the edges as for the white paint.  I will leave such decisions to you.