Gloss coat over decal.

I've had problems in the past because I got in a hurry to get the final gloss coat applied - in otherwords, the decal still soft from the decal setting materials.  You need to ensure the decals are completly dried - I would reccomend a minimum of 24 hrs of drying time before you put either a clear gloss or flat coat over the decals.

What are you using for a gloss coat?

 If you are using Testors Glosscote, be very careful and do not let it go on too heavy. Being a laquer, it can dissolve the paint underneath (also damaging the decals).  Always mist Testors Glosscote and Dullcote on

No problem at all, just as if you were dull coating them. Just let them sit for a day or so after application so that they are completely dry.

Thanx, my first custom paint and decal and spent a bundle on the decals. Didn't want to ruin them.

You can. I've never had any trouble gloss coating over decals.