I just stumbled across this process on Youtube.
He laminated the board with a solid yellow resin mix.
Followed by a solid black mix for the filler coat.
The sanding stage then removed a lot of the black and created the distressed look.
Then finished off with a clear finish coat.
Good luck
Shrednaught rocks, it would be great to see some new videos but the one’s he’s done are awesome! I knew I’d watched a video on how to create this effect but couldn’t find it!