If you’re working indoors, open a door or window to the outdoors to avoid breathing in fumes. Wear old clothing that you don’t mind getting dirty.
Anywhere you see a darker spot on your piece of wood should be covered up with a stain blocker.
If you’re going to paint over the entire piece of wood, which isn’t required to cover the knots but can help create an even paint layer, sand the entire piece of wood as well.
Look for a clear or white shellac-based stain-blocking primer. BIN by Zinsser is the most popular brand of knot stain blocker.
Avoid applying too much stain blocker to one area of the wood; otherwise, it will get too clumpy. That said, read the manufacturer’s instructions, as some blockers might need more than one layer. If your white stain shellac doesn’t completely cover the knot, don’t worry. You can apply another coat once the first one has dried and been lightly sanded.
If you touch the stain blocker and it still feels wet or slightly sticky, it hasn’t dried completely yet.
If you painted the entire piece of wood, sand the whole surface lightly as well.
Water-based paints like latex or oil-based paints like alkyd-based paint are both safe on wood. If you’re using a roller, pour a small amount of paint into a tray to make the application process easier. Use back and forth strokes of the roller or paint brush to create an even layer of paint. If you’re just painting over the knot, make sure the paint color is an exact match and use brush strokes that go in the same direction as the previously painted layer.
Read the instructions that come on your can of paint to find out how long it will take to dry, as all types of paint are different. Consider adding a sealant to the wood after you’ve applied a regular coat of paint for extra protection. Wait for the additional layers to dry completely before applying the sealant.
