Why I Got Off The Rag And Started Spray Finishing:

About five years ago I did some remodeling work on a friend's house. I installed several rooms of complex new baseboards, window and door casings, and new doors, all of which were bare oak that need to be stained a dark color.

One of the first finished items to be installed was a pair of French doors with 15 panes of glass each. I applied the stain the usual way... with a brush and rags. It was terribly tedious, especially around the glass, and I had a difficult time getting the color to appear uniform. I wasn't looking forward to brushing 2 or 3 coats of urethane on all that intricate millwork. I knew there had to be a better way.

When the stain was dry, I decided to try applying urethane using several spray cans of Minwax polyurethane. It worked great. It was quick and the finish was nearly flawless. I think I used 6 or 8 spray cans, at about 5 bucks each, to apply 2 coats. At that point I realized that I could apply ordinary polyurethane, bought in a gallon can, with some type of High Volume Low Pressure spray gun.

I looked at HVLP sprayers that use a series of turbine fans to pressurize the air. While highly rated, I couldn't afford to spend upwards of $1,000 for something I knew I wouldn't use often.

For less than $100 I bought a Porter-Cable HVLP spray gun that connects to an ordinary air compressor, of which I already had two. My smallest compressor, which develops 1.5 HP, is plenty powerful for this spray gun. A couple of years later, while repainting my truck, I bought another spray gun at a local automotive paint store for $150.

While I occasionally apply stain or urethane with a brush, especially on very small projects, I regularly use my spray guns to apply stain and urethane on wood trim, window sashes, doors and furniture.

Airless Sprayers? Just after I bought my first HVLP spray gun I also bought an inexpensive Wagner airless power sprayer. It develops 2600 PSI and cost about $100. While the tool works okay for certain types of finishes (heavier stuff, like deck stain) it doesn't have the fine control needed for stain or urethane. Higher priced airless sprayers may work for finishing wood trim, but I have no experience with them.

About The Stain:

I used a 2-part stain system from M.L. Campbell, which I bought at a local paint store. This professional-grade product is meant for cabinet manufacturers, but may be available to do-it-yourselfers. The first part is a tinter called "Microton" (pronounced micro-tone) and is meant to soak into the wood. The tinter is like a dye and doesn't have grain-concealing solid particles of pigment. It can be recoated in 5 minutes, which is unbelievably fast compared to consumer-grade stains.

The second part of the stain system is more similar to conventional stains because it has pigment. If it's not applied too thick, this part can be covered with urethane or lacquer in as little as 30 minutes. This stain is NOT meant to be wiped off like consumer-grade stains. I have wiped off the excess stain on other projects, and I like the appearance... but it requires working fast.

Both parts of the M.L. Campbell stain system are acetone-based, so they can be cleaned up with acetone, which is also known as nail polish remover.

Conventional slow-drying consumer-grade stains can be sprayed, and are the best products to start learning with. I'll discuss this more at the end of the article.

Spray-Staining With Conventional Stains:

When I bought my first HVLP spray gun in 2004, I was in the middle of an old house remodeling project that involved several rooms with stained oak trim. I had been using Old Masters brand of stain in a Red Mahogany color. This conventional mineral spirits-based stain has a reddish-brown color and is meant to be applied like most consumer-grade stains: Apply with a brush, wait a few minutes, then wipe off the excess with a rag.

When I bought my first spray gun, I tried spraying some Old Masters stain on some scraps of red oak. After making many adjustments to the spray gun, I was very pleased by how quickly and uniformly I could apply a coat of stain. I discovered that the beauty of spraying is that I could apply just a little bit more stain to the wood if I needed a darker color. There's no way you can apply a half-coat of stain using the brush-and-wipe technique, but with a sprayer I could apply a "one-tenth" coat to slightly darken the wood finish.

Sometimes the spray would leave speckles or spots on the wood, so I would simply use a small soft brush to spread the stain around, though sometimes this left streaks or brush marks.

The first few times I sprayed this conventional stain, I wiped off the excess with a soft cotton cloth after waiting 15 to 20 minutes. If I wiped off too much, I was able to spray another very light coat of stain and brush it smooth.

Eventually, I was able to perfect my technique and apply just the right amount of stain, brush it smooth, and not wipe it.

The main drawback of consumer-grade stains like Old Masters or Minwax is that they are based on mineral spirits or similar low-volatility solvents, so they dry very slowly. These stains typically take 12 hours or more to dry before they can be coated with urethane.

I have brushed on urethane to stained boards that were not completely dry, and the stain gets "picked up" by the combination of the solvent dissolving the stain and the brush agitating the stain. The end result is a stain job made ugly with accidental light and dark patches, and no ability to fix the problem without completely stripping off the finish.

However, I often spray urethane over stain that is not completely dry, and I can't see any problem. I just notice that when I scuff-sand the first coat of urethane, the dust  has the color of the stain. For the later coats, the dust appears white as it normally would.

The bottom line is: Applying stain and urethane with an HVLP spray gun is fast and gives a high-quality finish. It requires a modest investment in equipment, some sensible precautions, and some time to develop the skill.