I was experimenting with a few weathering possibilities for the deck. I took four planks and painted the edges with Judea bitumen. the paint seeped onto the surface of the plank by mistake but i continued to put a satin finish on then and once dye wiped on and off Judea bitumen again. Where the edge paint seeped onto the front of the planks made a realistic look to the weathering of the wood. Has other builders try this? Is this a common technic?