This article gives general information about waterslide decals and a step-by-step guide showing how they should be applied.
Waterslide decals are by far the most popular way of applying unit markings and other graphics to scale models. This is partly because most model kits are supplied with appropriate waterslide decals, but also because they generally work very well in most situations and it is relatively easy to get a good result.
Waterslide decals can vary considerably in quality. Sometimes they are too thick and will stick out on the surface of the model and will not lie flat over surface details. At other times, they may be too thin and might disintegrate during the application process. If the printing is not sufficiently opaque the underlying colour of the model will show through. Occasionally, they may be printed out of register where the different colours are not printed over each other in the right place. However, standards have been continually increased over the years and the vast majority of decals are now very good quality.
Decals that are applied well will greatly enhance a model, but when they are applied badly they will ruin a model that otherwise would have been excellent. Providing a few basic rules are followed, it is quite easy to get good results.
Description of Water Slide Decals
Water slide decals or transfers consist of several layers. There is always a sheet of backing paper to which everything else is attached. On top of the paper is a layer of water soluable glue. The actual markings are printed on the glue film and on top of that is a carrier film.
When placed in water for a few seconds the glue will become slippery and allow the decal to literally slide off the backing paper and on to the model. A single spot of dishwashing liquid dissolved in the water will help the decals to slide of the backing paper and on to the model. Hopefully there will still be sufficient adhesive on the back of the decal to stick to the model.
It is vitally important to have a gloss or semi-gloss surface to apply the decals. If the model is painted with matt/flat paints, then the surface needs to have a couple of thin coats of gloss varnish, or Klear/Future to give it some shine.
Matt/flat paints leave a surface that is microscopically rough. If a decal is applied to such a surface then it will only make contact with the high points on the surface of the paint. When dry there will be thousands of microscopic air pockets under the decal which will appear as ‘silvering’ and will look terrible.
Some modellers will only varnish those parts of the model where decals are to be placed, but there is a danger of producing a ridge at the edge of the varnish. Most modellers will varnish the entire model because this is not only needed for decal application, but also makes it easier to apply filters and washes to the model.
The model can always be returned to a matt or semi-gloss finish after decal application with another coat of appropriate varnish.
Although waterslide decals are intended to stick well to the model, in practice they only do this in ideal circumstances, such as when there is a perfectly flat surface. If the surface undulates or has texture, of if the decals need to fit over or around surface projections, then they need a little help.
Many companies produce two part decal solutions to help with the application of waterslide decals. The first part is painted on to the surface of the model. This makes it easier to slide the decal into the correct position and improves the adhesion of the decal. The second part is painted on top of the decal. This softens the decal and helps to make it conform to any irregularities in the surface. This second solution can be reapplied if the decal has not fitted well around any surface projections.
Once the second solution has been applied, the decal may appear to wrinkle and may look dreadful. However, do not touch it at this stage because it will be extremely elastic and fragile. As it dries the wrinkles should disappear and the decal will shrink back on to the surface and cling fast to any surface details.
These decal solutions vary in strength between different manufacturers. It is advisable to experiment a little when you use these solutions for the first time, or change brands.
When To Apply Decals
This will vary from model to model and it may be advisable to apply some decals at a different time to others. Normally, the best time to apply them is just before weathering, so that they look like they have been weathered with the rest of the vehicle.
Step By Step Guide
The following shows the application of a decal to Tamiya’s 1/35th M113 armoured personnel carrier. The first stage is to prepare your work area and make sure you have everything to hand:
- Decal sheet
- Saucer of water + a drop of dishwashing liquid
- Decal solutions
- Small brushes (one for each decal solution)
- Small scissors
- Paper towel
- If the decal is thin and the paint underneath shows through (often the case with white decals) then try painting over the decals with thinned paint using them as a template.
- If the decals have to fit around surface projections, then cut them into small pieces and apply them separately.
- If there are air bubble under a decal when it has dried then prick it with a pin a few times, paint decal solution on it and press down on it with a damp paper towel.