How do I stop my model decals silvering?

Decals are printed on a clear carrier film that is stiff and perfectly flat. A matt paint film is deliberately rough at a microscopic scale, so the flat film bridges from peak to peak and traps air underneath. That air reflects light and reads as a dull silver haze around the marking. Nothing about the glue is wrong.

What you'll need

• Gloss clear coat
• A decal setting solution and a softening solution
• Cotton buds and soft tissue
• Tweezers and a fresh scalpel blade
• A dish of warm water

Step by step

1. Gloss coat the area before any decal touches it.This is the single step that prevents silvering. A gloss surface is smooth, so the carrier film sits in continuous contact with no air between. Let the gloss cure hard before wetting anything.
2. Cut the decal close to the printed marking.Excess clear film is more area to silver and more edge to see. Trimming close with a fresh blade makes the film edge much less visible once varnished.
3. Soak until it moves, then take it out.Warm water, a few seconds to half a minute. The moment the decal slides on its backing paper it is ready. Leaving it in until it floats free washes away the adhesive and you lose control of it.
4. Wet the model surface before you slide it on.A drop of water, or better a drop of setting solution, on the target area. It lets you slide the decal into position rather than having it grab where it lands.
5. Press the water out from the centre outwards.With a damp cotton bud, roll rather than drag, from the middle of the decal towards each edge. The water you push out is water that would otherwise dry as trapped bubbles.
6. Apply a setting solution and then leave it alone.Setting solution softens the carrier film so it slumps down into panel lines and around rivets rather than tenting over them. It will wrinkle alarmingly for a few minutes. Do not touch it. It flattens as it dries and touching it while soft tears it permanently.
7. Use a stronger softener only where you need it.Over compound curves and heavy raised detail. Strong solutions can craze a decal or attack the paint underneath, so build up with repeated light applications rather than flooding it once.
8. Seal with a clear coat, then a final matt or satin coat.The clear seals the decal edge. The final matt coat over the entire model brings the gloss area, the decals and the base colours back to a single sheen, which is what makes the markings look painted on.
9. Rescue a decal that has already silvered.Prick the film with the very tip of a fresh scalpel, along a panel line or inside a dark area of the printing where the hole will not show, then flood setting solution into the hole and press down with a cotton bud. The solution reaches the trapped air and the film collapses onto the surface.

Tips

• Old decals go brittle and shatter. Sealing an old sheet with a coat of decal film or clear varnish before cutting holds the pieces together and often saves an out-of-production set.
• Some kits have very thick decal film that will not conform whatever you do. Aftermarket replacements are usually printed on far thinner film and are worth the cost on a model you care about.
• Never let a decal dry out part way through positioning. If it starts to grab where you do not want it, more water or setting solution will free it again — pulling at it will not.

Common mistakes

• Applying decals over a matt finish — It guarantees silvering. Matt paint is rough on purpose, and no amount of setting solution can push a stiff film into contact with a surface made of microscopic peaks.
• Touching a wrinkled decal — Setting solution deliberately softens the film to near-tissue. It always wrinkles before it flattens. Every attempt to smooth it while soft tears it, and torn decals cannot be repaired.
• Soaking decals until they float off — The adhesive dissolves into the water and you are left with a film with nothing to hold it. Slide it off the backing onto the model instead, taking the adhesive with it.

If it doesn't work

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