Then I brushed on my first coat of water-based acrylic finish and took almost all the colour off. (Damn!) This didn't happen on my test panel, but still I probably should have expected that a dye that dissolves in water would also dissolve in water based finish. I managed to get it so there aren't streaks, so the piece looks OK (the friend I'm making it for doesn't know the colour I was aiming at, so the colour I got will do just as well).
However, in hopes of never experiencing this pain again, I thought I would ask for your advice on how to avoid it. I can think of some ways:
1 - Spray the finish. I think it was the act of wiping the wet brush over the surface that took off the dye and that a spray coat of stain might not have caused it. However, this would require a spray booth and a bigger compressor, both of which are problems. Anyway, I'm not sure it would work. If I sprayed finish onto a vertical surface, it seems like it might dissolve the stain and cause it to run downwards.
2 - Sack up and use oil-based polyurethane. I hate and fear oil based finishes, not least because my shop is right next door to my furnace room, but it might be time to learn.
3 - I have read that a thin coat of dewaxed shellac can be used to seal the stain in the wood, and then water-based finish can be applied over it. Has anybody tried it? Are there problems with the finish curing improperly, or peeling, or otherwise failing?
4 - Somebody will suggest just not staining the wood, and instead buying wood that is naturally the colour I wanted. I am seriously considering it for next time. :)