Sealing decals after application?

Alclad is the only product which when sealed by its own product its "shine" just disappears .

Yes.  By that I mean there are a number of overcoats, including clear acrylics, clear enamels and clear lacquers that work well.  The only time I do not overcoat after decaling is over Alclad- I don't like the effect, but decals seem to adhere very well to Alclad, so I leave them be.

Well I assume you put down a gloss coat to put down the decals ? If you are going to have a flat finish then you would need to apply a flat clear to get rid of the gloss.If you want it shiny then overcoat with gloss just to protect the decals from the weathering process.

Acrylic or enamel and or synthetic laquer clear gloss coat used , it's best to use Testore Dullcoat airbrushed at 20 psi .If you can find flat non- spar clear varnish ,it will work better.Thin w/ mineral spirits.