I am making something for outdoor use and I've painted it with a matte exterior latex paint. I'm satisfied with the protection that the paint will offer but I'm experimenting with ways to make it look nicer.
Right now I am considering glossy finishes. I have found that I much prefer the appearance and texture of shellac (de-waxed) to a high gloss spar urethane.
I don't really need good scratch resistance for this particular piece, and the paint should protect the wood enough from moisture and sunlight.
I'm also not too concerned about color changes over time as long as it is uniform. The paint is just brown, and maintaining the precise brown isn't super important.
My question is, how should I expect a fairly thick shellac finish (over paint) to behave outdoors over time? It will be exposed to sunlight, a wide range of temperatures, and plenty of rain, snow, and ice. Should I expect flaking? Spotting? Blemishes (I've heard it gets cloudy with moisture)? Other weird stuff? Or will it maintain its nice appearance? If it does get grimy, will it be prone to staining (with polyurethane a good wipe down with an all purpose cleaner takes care of it)?
I already own the paint and don't really want to buy another gallon of glossy paint; I'm trying to do this with the stuff I already have sitting around collecting dust on my shelves.