Ups and downs of spray finishing
Applying a finish to a project stirs up lots of emotions for woodworkers.
We’ve all seen how the grain and colour come alive when we wipe on that first coat of oil on a plank of smooth wood. It’s one of the highlights of a project. A less satisfying feeling is when a finish isn’t applied properly and it detracts from the project, or maybe highlights the sanding and machining flaws in the piece. This is incredibly frustrating, as you’ve spent a lot of time and energy on the project already, only to come close to ruining it.
Recently, I’ve been spraying on water-based finishes to a few projects, as that’s either what the client wanted or that’s what the project dictated. Water-based finishes are generally quite clear, though they don’t “pop” the wood grain or bring out deep colours in the wood like an oil-based finish does. Like everything in life, there are pros and cons to water-based finishes.
I’m working on a black walnut bathroom vanity right now. The other materials and colours in the room are very subtle, clean and modern: off-white wall tile; a beige-grey floor tile; an off-white stone counter; and white walls. The two-sink vanity will provide the majority of the “punch” in this bathroom. After showing the client samples of oil-based and water-based topcoats, they opted for the water-based because it was a bit simpler and more modern than the extra-rich look the oil-based topcoat produced. I generally prefer the oil-based look, but I think this is the right choice for this bathroom.
The large, rustic coffee table I wrote about a few weeks ago was also finished with a water-based topcoat. The client wanted a very low-sheen look with virtually no buildup. I also had to spray it on, as the material the table was made with (barn board) had a lot of deep texture. Wiping it on would leave large amounts to pool in all of the recesses, which wasn’t the look we were after.
Grab the spray gun
I usually apply a water-based topcoat with my spray equipment. In the case of the textured coffee table, this was because it would be impossible to wipe the finish on. With the vanity in my workshop right now, it’s mainly because it’s a lot faster and the resulting finish will be very smooth and even.
Wiping on an oil is quite easy. Apply oil to a rag or directly to the wood’s surface, then evenly wipe it across the piece. It almost always turns out great. Spraying isn’t quite as simple. Not only do you need specialized equipment, but you need to have the skills and experience in order to apply an even coat without runs, sags, overspray, orange peel, blushing or a host of other potential problems. I hope I’m not scaring you away from spray finishing, as the upsides are huge. Having said that, you need to learn how to spray finish and then practice on scrap before tackling your latest project that you’ve already put a hundred hours into.
Pros and cons
You can spray on an oil-based finish, but the main downside is that cleanup is more involved. You don’t want to set up spray equipment to apply just a few coats of oil-based finish to a small project, as you’ll spend more time cleaning it than spraying. Water-based finishes are different, though.
Dry times are quite low with water-based finishes, which is great. And VOC content is a lot lower than oil-based or lacquer spray finishes. Aside from the speed of applying a spray finish, the final result is very smooth and uniform.
You do need to consider how to deal with the air you’re spraying in. Overspray is a part of spray finishing, and you don’t want to breathe it in. You also want to be careful around an open-flame heat source. A spray booth is a great starting point when spraying larger items or lots of items, though there are smaller, simpler measures that can help when spraying less material.
Like anything, there’s a time and a place for spray finishing. To me, spray equipment is one of the more important tools to have when it comes to applying a finish. A finish is arguably the most important single aspect of a project (You disagree, do you? Comment below!), so I like to do everything I can to ensure I can apply the correct finish in the most appropriate way.
Further resourcecs
Sure, it takes some time to learn how to spray on a finish, and there’s the obvious cost of the spray equipment, but neither of these are too much of a challenge. Spray equipment doesn’t have to break the bank, and learning spray techniques are just a click away. I wrote an article titled “Spray finishing – tips for getting started” that you can read here:
Mark Salusbury wrote an article about how he made a portable spray booth for a small shop. Karen McBride wrote about her portable fabric spray booth. And as a general introduction to the topic of HVLP spray finishing systems, read this article by Bill Perry.
Once you finish these articles, you’ll be well on your way to learning about the great world of spray finishing.
Now that I’ve talked you into this approach to finishing, I have to head to the shop and apply the final coat of finish to some walnut. It’s going to turn out great. With a bit of practice you’ll get as much satisfaction out of spray finishing as you get from wiping on a finish.
Rob is a studio furniture maker and the editor at Canadian Woodworking & Home Improvement. Instagram at @RobBrownTeaches
