The reason one will want a good-enough gloss coat under/before the decals, is to make a smoother surface for the decals to adhere to. Problem is usually, that without a good-enough gloss coat, you get air trapped underneath the decal, which is called "silvering" and looks bad. A good-enough gloss coat under the decal prevents this. You also want a gloss coat over the decal, to avoid messing up the decals when adding any weathering effects, or say a pin wash. Adding a gloss coat over the decal, also helps hide the edges of the decals, as the gloss coat will eventually fill the cavity next to the edges of the decals. Apparently some decals are thicker than others.
In my experience, adding a gloss coat, can be tricky if you insist on getting a very smooth finish, which may require more than one layer of gloss coat. Another problem is that, you also risk a non-smooth surface, if you airbrush on the gloss coat wrong. I honestly am not 100% sure how to best do this. I only know that, I can airbrush on that stuff with ca 7 psi wet-in-wet, and in patches, to avoid blowing air, or creating overspray, over a surface that has gloss coat liquid on it. Problem then is, too much liquid, and the gloss coat will run, or pool around details. Also make sure you have used a brush to remove dust and remains of sanded plastic from panel lines so that the panel lines aren't sealed with plastic dust in them.
6. November 2019 at 12:34:38