It's important when applying decals that you use Micro Sol and Micro Set or Vallejo Decal Set. Both of these can be purchased through Amazon. Although, we are considering carrying it in the future. Make sure you have both of these solutions to give your models the perfect decal application :)
Basically, Micro Set prepares the surface with wetting agents that cut the oils in new paint and it converts the adhesive on the back of the decal to make it a stronger and longer-lasting one. Micro Set also slightly softens the decal film to make it more flexible so that it will conform better to the model's surface. (It also can act as a decal remover.)
Micro Sol setting solution is needed for applying decals to the difficult or irregular surfaces found on models. It completely softens the decal, allowing it to drape onto the surface of the model, conforming perfectly to the surface.
If it's not adhering properly to the model, then using a setting solution can resolve the problem. Here are the steps for decal application:
1. First, apply gloss varnish to the area where the decal will be positioned. This step is important, and if you encounter problems such as a visible border or air bubbles, it’s most likely that the surface was not smooth enough. So make sure you get a glossy finish. Allow some drying time in between, grab a coffee ;)
2. Cut the decal out from the sheet with a hobby knife and, gripping with a pair of tweezers, dip it into the water for a few seconds and set it aside. The exact length of time the decal needs to be submerged in water depends on various factors, including the age of the sheet. Ten seconds is usually enough, but if it doesn’t slide off easily just stick it back in for a few more seconds.
3. While the decal is soaking and lifting from its backing, brush some Microset onto the area where the decal will be applied.
Slide the decal off it’s backing onto the model and position using a paintbrush. Brush more Microset over the top, and then leave for a few moments to soften.
4. Using a moistened, but not wet Q-Tip, very gently press the decal down on to the surface, removing the excess fluid and flattening/smoothing the decal as you go. Tamiya cotton buds are good for this because they are tightly wound, so cotton fibers won't stick to the decal.