Could be a sticky situation
For protecting wood furniture from the elements, synthetic varnish becomes a strong ally. Just wander down to any yacht harbor and check boats with shiny wooden rails and trim: nobody knows better than a boat owner how to avoid the trials of sun, storm, and salt. But a sailor also knows patience. Applying the thick, slow-drying varnish will help hone those skills as well.
Get ready :
Bring your furniture item into a temperate, dust-free room if possible: varnish is very sticky and you'll want to avoid creating a bug and leaf college. If working outside, choose a moderate, windless day.
Get your surfaces ready for varnish: remove any excess paint, sand the surface to the desired smoothness, and dust out any residue from the corners.
Select the proper varnish
Most varnishes are alkyd, and those containing tung oil are more water-retardant than those with linseed oil. Alkyd is not as unyielding as polyurethane and often more attractive. It is the best choice for fine wood pieces.
Polyurethane is best used on "everyday" pieces that take a real beating. Drying time is fast (4 hours. instead of the usual 24) and you don't need to go back and level your brush strokes. But by providing such a truly solid layer, polyurethane more resembles plastic than wood: avoid using it on fine wood. Polyurethane varnish is so tough it often requires an electric sender to remove.
Use phenolic resin or spar varnish for outside work or for boats. These varnishes are too thick and will yellow too much over time for fine wood or interior work.
Prepare your area
Lay down enough newspaper to exceed your project's width by two feet in each direction. This will help protect your floor from drips. Take a tack cloth and wipe up any trace of dust or sanded paint on the surface of your furniture.
Learn the stroke
Chart out your areas of attack in a way so you don't have to stop in the middle of a panel. Shake any dust off your brush and fill it with varnish. Brush across (not with) the grain with long strokes. Repeat the process, making a one-inch overlap from where your last stroke ended to avoid patches.
Even out and level the varnish surface
Once you've covered the panel you will go back over and work with the grain. Remove any excess varnish from your brush on the rim of the can, then brush lightly over the wood surface. If too much varnish builds up on your brush as you continue, swipe it along the rim of the can to dry it off. Brush over the wood surface only once, making the coat as smooth and even as possible.
Perform the art of tipping off
Now for the last smoothing step.
Tipping off is a dry brush method of using just the tip of your brush to do away with the last brush stroke (or finger) marks. Moving in rows with the grain, hold the brush perpendicular to the surface and barely stroke the surface of the wood.
Prepare properly for the second coat
It is a good idea to wait one full day before embarking on your second coat. First you must use the sandpaper to softly "take back" (usually in one pass) the first coat. Do this by sanding gently with the grain into the first layer of varnish. You want to rough up the surface enough so the second layer can set without going through to the bare wood. Clean the surfaces with the tack cloth. Now you can repeat the varnishing process again!