When I first got into woodworking, someone asked me what finish I was using. I stared blankly and said “…finish?” Turns out slapping paint on something and calling it done is not quite how it works. Since then I have learned way more about finishes than I ever expected.
Let me break down three of the most useful ones: varnish, polyurethane, and Danish oil.
Varnish: The Classic Workhorse
Varnish has been around longer than any of us. It is a combination of oil, resin, and solvent that dries to form a hard protective film. The stuff on antique furniture that still looks good after a hundred years? Probably varnish.
I use varnish mainly on outdoor projects because it flexes slightly with wood movement and handles weather better than most alternatives. The rocking chairs on my front porch have marine varnish and they have survived five winters so far.
Application is straightforward but slow. Brush on a thin coat, wait for it to dry completely (usually overnight), sand lightly with fine paper, wipe off dust, repeat. Three or four coats minimum for real protection.
The downsides? Varnish can yellow over time, especially in direct sunlight. And cleanup requires solvents which is messy and smelly. But for durability and that traditional warm look, it is hard to beat.
Polyurethane: Modern Protection
Polyurethane is basically the evolved version of varnish. It forms a tougher, more scratch-resistant surface which is why it ended up on most of the furniture made in the last fifty years.
You have two main options: oil-based and water-based. I have strong opinions about both.
Oil-based poly adds warmth to the wood – a subtle amber glow that looks great on darker woods and gives lighter woods some depth. Drying time is slow, usually 24 hours between coats. The smell is strong and lingers for days. But the finish is tough as nails.
Water-based poly dries clearer and faster. I can get three coats done in a day if I start early. Way less smell which matters when I am working in the garage attached to the house. The trade-off is slightly less durability and it can raise the wood grain which means more sanding between coats.
For tabletops, floors, anything that sees heavy use – polyurethane is my first choice. My kitchen table has oil-based poly and has survived years of daily abuse from my family.
Danish Oil: The Easy Option
Danish oil is what I recommend to beginners because it is nearly impossible to mess up. It is a blend of oil and varnish that you wipe on, let soak in, and wipe off. That is it. If you can rub oil on a cutting board, you can apply Danish oil.
The finish you get is more natural looking than varnish or poly. It penetrates into the wood rather than sitting on top, so you still feel the wood grain rather than a plastic-like film. On figured woods like tiger maple, Danish oil makes the grain pop in a way that film finishes just do not match.
Protection is moderate – better than bare wood but not as tough as multiple coats of poly. I use Danish oil on items that will be handled but not abused. Jewelry boxes, picture frames, small decorative pieces. For my workbench I use it because I like how it looks and I do not mind reapplying once a year.
The nice thing about Danish oil is that refreshing the finish is just wiping on more oil. No sanding or stripping needed. With varnish or poly, once the finish is damaged you often have to take it down to bare wood and start over.
Which One Should You Use?
Honestly it depends on what you are making and how much abuse it will take.
Need maximum durability and do not mind the application time? Polyurethane.
Building something for outdoors or want that traditional furniture look? Varnish.
Want easy application and a natural feel? Danish oil.
There are plenty of other finishes out there – lacquer, shellac, pure oils, wax, the list goes on. But these three cover most situations and all of them will give you good results if applied properly.
My only real advice: try different finishes on scrap wood before committing to your actual project. Every finish looks different on different woods and what looks great on oak might look weird on walnut. A test board takes ten minutes and saves a lot of regret.
