Water-based polyurethane varnish has some advantages over traditional varnish. It dries quickly and it can be cleaned up with water. Finish wood with water-based polyurethane varnish by brushing it on, letting it dry and sanding it down. Repeat this process until you get a shiny and smooth finish on the wood.
Purchase water-based polyurethane varnish. Like paint it comes in high-gloss, semi-gloss, satin, matte or flat. Gloss is shiny and a little tougher. Matte is more subdued.
Choose a location to paint that is well-ventilated and free of dust.
Make sure the wood you are going to finish is sanded, clean and free of dust. Clean it with a tack cloth.
Stir the water-based polyurethane varnish well and pour some from the can into an alternate container. You will use the varnish in the alternate container.
Paint the water-based polyurethane varnish onto the wood using smooth, even strokes along the direction of the wood grain. Hold the brush as vertical as possible while painting.
Allow the water-based polyurethane varnish to dry completely. This can take as little as an hour, depending on the temperature and humidity. It should be dry to the touch.
Sand the varnish with 220 or finer sandpaper then remove any dust with a tack cloth. Repeat this process of painting, drying and sanding until you achieve the desired look.
Wait one week and then rub the surface with "0000" steel wool, clean it with a tack cloth and apply paste wax to get the best looking surface.
It's best to varnish wood if it's horizontal to avoid drips. Place the wood you are varnishing on a flat surface, such as a table or counter. Be sure to use a new, clean synthetic bristle paintbrush. Watch for drips and brush them out as they occur.
Do not dip your brush into the original can of water-based varnish to avoid contaminating the original varnish with dust and debris.