Julie,
What Max told me about sealing them is that there are different ways - and it's what you prefer.
The way I want - because I like painting on a very white surface, is to use (no acrylic!) Titanium white thinned with turps. You can use any color I imagine. From what I see, if you thin it too much though you'll still have the sinking in - so not too thin. Im going to practice with it with the small samples he sent me.
Another way he suggested was to put linseed oil on it and rub it in with your hand. The heat gets it in there good - then wipe off the excess. I will try that on a sample also, but knowing that the extra oil means you'd want your paint to to be oily on top of that - in other words - after doing that you couldnt have any turps (even just a bit from washing out a brush) on top of that.
He told me a couple other choices I believe -
but my memory is no good. Bill W did it a different way to seal it as well on a thread here.
Max reads these threads and can answer these better than I. Im hoping he will join here to answer some of these, but if not - you can email him at
[email protected]. He also has a forum on his site that answers some of this.
After I experiment - I'll let you all know my results though.