I want to mix linseed oil and a black oil based paint then thin it out with paint thinner so that I can spray it but I wanted to know if the reflective beads will work? I'm using them on 6" to 8" post or will it not stick to linseed oil?
In my opinion the beads will stick provided you select the appropriate size beads. If the beads are too heavy they might slide down. I suggest you experiment with a small section of post.
