Varathane is a water–based polyurethane sealer that adds shine to wood and latex–painted surfaces.
Spray urethane is commonly used for finishing painted surfaces, but it's also possible. Both oil- and water–based polyurethane products bond well to dried latex .
The water bourne acrylic that wdwerker mentioned is less likely to give the white paint a yellowish cast. Regular oil based poly has a distinct .
Hey, has anyone ever applied wb poly over latex to make it more durable and feel less tacky to the touch?
But can you put a spar varnish over latex paint?. I would use a good exterior 100% acrylic paint, probably over a good oil based primer.