Neil,

We sell the "tar stain" over here, and we call it Asphalum.

It makes a great stain, you can get many shades of color depending on the amount of tar and solvent that you mix. It can also be mixed to a transparent color, it works great on many woods.

We use to get pieces of tar, and thin it out with gasoline (petrol) as it worked faster then using turps, once it was a liquid then we would add the gum turpentine to make up the stain.