Painting Slates that have been previously used on a roof.
I am having trouble with my acrylic paint peeling off of slates that I have painted.
When kept indoors, there is no problem.
But these slates have been painted with the intent that they could be placed in an outside garden. I do top coat the side of the slate that has been painted with two coats of polyurethane that is specially made to withstand the outdoors.
Min-Wax Helmsman. W/Spf protection.
Unfortunately, I am finding that the painting isn't holding up.
Do you have any suggestions? This particular surface is not listed on your website.