Stain plywood cabinets to give them a darker, richer result than varnish or polyurethane products alone give you. The process involves preparation and drying time between coats, so it often requires attention over several days. You need sandpaper, a paintbrush and rags before beginning.
Sand the surfaces
Use sandpaper with progressively finer grit to ensure that surfaces are free of any rough spots where the stain tends to accumulate. Staining without preparation accentuates the minor imperfections that preparation eliminates.
Decide if staining is appropriate
Test the cabinet to see if you want to stain the wood. Wet a piece of the wood using paint thinner to approximate what your final product will look like without staining. Allow the thinner to dry before proceeding, regardless of your decision.
Apply the stain
Apply a gel stain using a brush. Wipe off the stain with a rag. If the gel dries before you have a chance to wipe it away, apply more stain and wipe immediately. Allow to dry thoroughly, and sand lightly before applying the finish coat.
Apply a finish
If you are inexperienced with applying finish products, choose a wiping varnish or oil-based polyurethane, as they offer an easier application. Follow the manufacturer's directions when applying.