Laquer over paint

Depends entirely on the first layer of paint and how long it has cured.

It will if the paint is lacquer-based, like Krylon or other fast dry spray paint (look for acetone, ketone, MEK, or toluene in the solvents listing). Do a test first. If a lacquer topcoat is incompatible with the base paint, it'll tell you in no uncertain terms.

Ok, thanks. Good to know.

You forgot to ask Paul if he was actually _after_ krinkle paint.

-- The ultimate result of shielding men from the effects of folly is to fill the world with fools. --Herbert Spencer

Wipe on a couple of coats of water based polyurethane varnish.

It happens far too often. Different solvents interreact, or paint isn't completely cured before application of a topcoat, etc. It's best to avoid that.

Use a high-quality exterior enamel instead, Paul. No extra protection or gloss needed. Someone recently mentioned Benjamin Moore Impervex and got a rise out of me. My mind centered on the middle of the word. :) It comes in acrylic (waterborne) and alkyd (solvent) bases.

-- The ultimate result of shielding men from the effects of folly is to fill the world with fools. --Herbert Spencer

Spray lacquer over Rustoleum oil-based will give him exactly what he wants.