[Jordan Baker]

It really depends on the specific brand of decal sheet you have. Most laser ones will not need a clear coat.

There are a few different brands of decal softeners available. I use the Micro Sol one. It works on most decals but sometimes I doesn’t. Your best bet is to try out some tests with decal scraps and see what works. There is too many variables to say which specific product will work.

A clear coat over the final decal once applied is to both help protect it and also better seal it. When used with model kits most apply the clear coat to try and get the carrier film to disappear from view so as to make the design of the decal look painted on. The clear also protects the decal from any weathering steps that come later.

Most model kit paints are some version of acrylic based. Years ago one always had to be careful as a lot of products were still oils based and could easily damage some decals or lower levels of paint.