How do I prevent paint or stain from bleeding?

For Christmas gifts, I decided to make two Chinese checker boards (from issue 186, Oct. 2008). But when I spray-painted the triangles on the plywood game board, the paint leached along the wood fibers [Photo above], messing up the crisp edges I was striving for. Where did I go wrong?
—Julie Penders, Fort Collins, Colo.

I'd like to make a Chinese checker board, but instead of painting the triangles I want to stain them with wood tones. How can I do this without the stain bleeding outside the triangles?
—Gary Wilson, McComb, Miss.

The answers to both dilemmas are similar. Julie, to stop paint from leaching outside the boundaries—defined only by masking tape—seal the bare plywood surface with three coats of either lacquer [Photo above] or dewaxed shellac, also known as sanding sealer, before spraying any paint. After this has dried, mask off the triangles and spray with paint [Photo below]; because the paint can't penetrate the sealed wood, it can't spread. After the paint has dried, top the game board with a clear-coat finish. Most of these will adhere nicely to the sealer and paint; but beware that lacquer will peel non-lacquer-based paint, so test first on scrap or simply topcoat with polyurethane to be safe.

Now, for Gary's staining idea: You can't seal the plywood first, because that would prevent stain from penetrating and binding with the wood. So instead, begin by scoring the triangle boundaries with a sharp marking knife or utility knife [Photo above], just deep enough to sever the surface veneer fibers. Then apply small amounts of stain with a fine artist's brush [Photo below], gradually working your way toward the scored edges and letting the stain wick its way ahead of the brush. Penetrating, oil-based stain—not gel stain—works best here, because you won't be able to wipe off any excess without messing up the board. Once you've stained all six triangles and allowed the game board to dry, top-coat with three or four layers of polyurethane, lacquer, or shellac.