Choosing the right finish is only half the job. How you put it on matters just as much. In Part 4, the last part of the series, we cover the different ways to apply a finish, why spraying gives the best results, and why we spray water-based finishes in our shop.
The M2 Finishing Guide
- Film vs. Penetrating Wood Finishes
- Oil Finishes and Hard Wax Oils
- How to Sand for a Smooth Finish
- How to Apply Wood Finish (you are here)
Applying Penetrating Finishes: Wipe On, Wipe Off
Oils, hard wax oils and other penetrating finishes are the simplest to apply. You're essentially rubbing the finish into the wood and taking off the excess:
- Wipe it on with a rag (or a brush, if you like).
- Work it into the wood. A buffing pad helps spread it evenly and speeds things up.
- Wipe or buff off anything that didn't soak in.
No special equipment needed, which is a big part of their appeal.
Applying Film Finishes: Brush, Roll or Spray
Film finishes are a different story. The goal is a nice, even, consistent film across the whole surface (hence the name), built up over multiple coats. You have three main options.
Brushes and Rollers
Brushing and rolling are the cheapest ways to apply a film finish, but definitely not the easiest. On long or large surfaces like a tabletop, it's hard to lay down an even coat. Every time you set the brush down, you're overlapping an area you already coated. That's why you have to keep a wet edge, always brushing back into finish that's still wet.
- Oil-based finishes are more forgiving with a brush. They dry slower, so they lay out and flatten better, and overlap lines tend to blend in.
- Water-based finishes dry much faster. With a brush or roller, you'll almost always see little lap lines between strokes.
Spraying: The Best Finish You Can Get
I don't think anyone will argue that the highest-quality finish comes from a spray system. Whether it's an HVLP (high volume, low pressure) gun or a pressure-fed setup, a sprayer atomizes the finish into a fine mist and lays an even coat all the way across the surface, with no brush marks and no lap lines.
For the toughest professional finishes, like the 2K and conversion varnishes we cover in Part 1, spraying isn't optional. They dry too fast to brush or roll.
A sprayer isn't super difficult to use. If you've never used one, there's a learning curve at the start, but it's much easier to get a high-quality finish with a sprayer than with a brush. If you plan to finish a lot of projects, it's worth investing in a sprayer. You don't need a professional booth to start, either. A simple plastic enclosure with an exhaust fan, like the one at the top of this post, works fine in a home shop.
Worried About the Mess? Spray Water-Based
The biggest reason people avoid spraying is the mess. Yes, overspray happens. That's exactly why we lean so heavily on water-based finishes when spraying.
Why spraying oil-based finish is a pain
- It's sticky. Oil-based finish dries slowly, so overspray clings to everything around you and leaves a tacky residue that's a nightmare to clean up.
- It's flammable. Oil-based finishes are almost always flammable. A cloud of finish mist in the air near a spark or flame is a serious fire hazard.
- Cleanup takes solvents. You can't clean the gun with water. It takes mineral spirits or other solvents, and that waste can't go down the drain; it has to be disposed of properly.
Why water-based is easier and safer
- Overspray dries before it lands. Anything more than a couple of feet from what you're spraying usually gets a light powder at most, which you can sweep, brush or blow away. It doesn't stick.
- Generally not flammable. Much less of a fire hazard in the shop.
- It dries faster, so you can recoat sooner.
- It cleans up with water.
That's a big reason many professional shops have switched to water-based finishes, and it's why we use water-based finishes almost exclusively in our shop.
⚠️ Always wear respiratory protection when spraying, even with water-based finishes. Use a respirator rated for spray finishing, and follow the safety info on the product label.
Spray Gun Care Isn't as Hard as You Think
Cleaning and maintaining a spray gun is less daunting than most people think:
- Clean it every time you use it. No exceptions.
- Learn how your gun works. Once you understand how it works, you'll understand how it fails, and troubleshooting gets easy.
- Replace wear parts. Like any tool, guns have seals, tips and filters that wear out and need replacing.
With water-based finishes, cleanup is even simpler, since water is all you need to flush the gun.
The Takeaway
- Penetrating finishes go on with a rag or buffing pad: wipe on, work in, wipe off.
- Brushing and rolling are cheap but tricky on big surfaces. Keep a wet edge, and expect lap lines with water-based finishes.
- Spraying gives the best results, is required for 2K and conversion varnish, and is worth the investment if you finish often.
- Water-based finishes are the easier, safer choice for spraying: less sticky overspray, less fire risk, and water cleanup.
That wraps up the M2 Finishing Guide. New here? Start from the beginning with Part 1: Film vs. Penetrating Wood Finishes.
Ready to finish your next project? We carry the General Finishes line we use in our own shop, including water-based Enduro topcoats and Enduro Conversion Varnish.