Quality generic and custom paint masks, vinyl decals, and dry rub decal kits for modellers.

Simulation - Paint Masks for a Roundel.

As a minimum you must have looked at the following pages before reading these instructions:

Objective of this workshop.

There are a number of ways paint masks can be used. In this instruction sheet I will show you how to apply the roundel in a simulation using the recommended application process.

Round insignia is different as it only needs one registration point to secure alignment of the mask.

Important factors to repeat. You must prepare paint masks in a clean environment free from dirt and airborne dust. Paint masks are best applied at room temperature as this increases the ability of the vinyl to conform to compound curves.

The masks to be used

The RAF "C" roundel is built up of 3 colours, blue, white, and red. Insignia produced from a sequence of ever decreasing circles is usually painted in order from the largest circle to the smallest circle at the centre.

To paint multi layered insignia you really do want to be using quality branded paints with high pigment levels that will cover well with low film thickness.

1.	Position the registration pin. Following the sequence order for the masks, the first to be used will be the "A" mask. This mask will provide the outline for the blue circle. Always take your time positioning the mask on the model to ensure it is exactly where it should be. 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 pin (see separate instructions). As there is only one pin to install it should be relatively easy to fix. Use 2 short lengths of high tack masking tape to hold the registration pin in position as shown opposite.

2.	Important to check . . . It is very important to ensure the masking tape securing the registration pin does not have a radius greater than that of the smaller circle in the sequence. As there are 3 masks in this roundel, the smallest is the one labelled "C". Measure the radius of the circle and ensure there is a good margin. You will see later why this is important!

3.	Test fit the roundel. Fix the roundel to the pin to be sure it is located correctly.

4.	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!

5.	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 registration hole as guide for the centre (see opposite). 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.

6.	Re-fit the silicone paper strips Return the silicone strips to the paint mask, but position each strip a few millimetres short of the centre line of the registration mark 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.

7.	Re-fit the mask. Turn the mask over and re-fit the registration mark over the pin. The exposed strip of mask should run parallel to the wing spar. Rub your finger down the centre so that the exposed mask and application paper takes grip on the surface.

8.	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 along the centre.

9.	Fix the mask down. Return the mask over the surface and hold the edge a few centimetres above the surface as shown opposite. Then with the fingers on your other hand begin wiping to and fro, starting from the centre section working your way to the outer edge steadily and progressively. Note: There is no need for excessive pressure!


10.	Remove second silicone sheet. Lift the opposite long side up and remove the silicone paper.

11.	Fix the mask down. Fit the rest of the mask down as in (9) above working slowly from the centre of the mask to the outer edge. Remember: There is no need for excessive pressure!

12.	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 down the middle and as close to the registration hole as possible. Pull the tape with gentle pressure at 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!

13.	Remove remaining tape As (12) above remove the remaining tape. Take care not to catch the registration pin and introducing excessive strain. This can cause slack in the application pins, which will eventually result in poor alignment of subsequent masks. If the application tape needs trimming to clear the registration pin use the scalpel blade!

14.	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 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 it 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. Remove the disk of paint mask from the registration pin used to hold the registration hole. Now mask the rest of the model to protect it from over spray.

15.	Spraying. As this is a simulation I will not be spraying any paint. You should follow all of the 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 and I also recommend you only spray the areas that need spraying. Avoid spraying onto the masking tape at the centre as this can create small ridges of paint which will be visible through the last colour.

16.	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. 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.

17.	For this simulation. The roundel is a difficult marking to simulate colour with vinyl. In the image opposite it shows a clean white disk of "paint" with a clean line at the centre. In reality this would go from a solid blue paint, fading away towards the centre masking. It is very important that you minimise the build up of paint in the centre!

18.	Prepare the second "B" mask. The second mask should be prepared just like the first mask from section (4) 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!

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

20.	Remove the application paper. Remove the application paper as before making sure the paint mask does not lift.

21.	Rub down the paint edges. Rub down the paint edges as previously to seal the mask. Remove the disk of paint mask from the registration pin used to hold the registration hole. Now mask the rest of the model to protect it from over spray.

22.	Second colour applied. Again this is a simulation so the white is represented by a disc of white vinyl.

23.	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. Continue to peel the mask back at 180° to the surface following the outline of the painted edge.

24.	Prepare the third "C" mask. The final colour is the red circle in at the middle of the roundel. Prepare the decal as previous.

25.	Apply the mask. Apply the mask to the surface as normal.

26.	Remove the registration pin. As the registration pin sits in the middle of the area to be painted red it needs to be removed. Take care not to damage your model as you do this. I use a sharp scalpel blade upside down to cut the masking tape.

27.	Remove masking tape. With the masking tape cut away the registration pin can be removed. Lift the masking tape carefully from the surface.

28.	Cleaning the surface. It is advisable to check for ridges of paint that could now be visible with the masking tape removed. Sand, or wire wool to remove and unwanted blemishes. If you are going to do this be careful not to catch the edge of the paint mask! Also look for deposits of adhesive from the masking tape and remove them with the minimum of suitable solvent.

29.	Spray the final colour. And finally the last colour can be applied. As previous, this is a simulation so the red is simply a disk of red vinyl.

27.	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. Continue to peel the mask back at 180° to the surface following the outline of the painted edge.

27.	The finished item. After the mask is removed give the insignia one final light rub over with "000" wire wool (optional) and the job is finished. Perfect insignia every time!