How to Get a Perfect Finish in a Dusty Shop
My troubled past
Wood finishing used to be one of the biggest mysteries and biggest sources of frustration for me. I grew up with a friend who’s family owned car painting business, and that made sense to me. I just always assumed you needed a paint booth, several thousand dollars of equipment, and years of skill to be able to properly finish something.
First of all, a lot of people refer to this process as how to stain wood. Make no mistake, there is no stain whatsoever in this process! Staining is often confused with finishing. I’ll address staining in a future article though. Like a lot of you, I read every article, I watched every YouTube video, and I was determined to be able to finish the like the pros in my dusty garage. Eventually I started to have a little success. I could turn out a decent product using Arm R Seal and buffing with soapy steel wool after curing. When I started making black resin and wood tables, that trick just wasn’t enough anymore. The black resin showed every imperfection. All those fine steel wool marks looked like I washed a black car with… well, steel wool. I was back to square one. So for about a year I opted to send my tables out to be professionally spray finished in one of those big shops. Eventually, I discovered this method i’m about to go over, and I haven’t looked back. Rarely in life do you find something that is easier, cheaper, and delivers a better finished product. But this technique is all of those things. Unlike a polyurethane or a varnish. This finish allows you to actually feel the wood grain, not put a plastic coat over it. It is similar to a linseed oil finish. With much, much better protection.
Tools and materials required
Osmo 3054 (instead of 3043)
It all starts with sanding. Which means you need a good orbital sander. You don’t HAVE to have a professional sander like I have. But you need an entry level orbital sander at the absolute minimum. We are long past the days of hand sanding with folded sheets of paper and a block of wood. If you care enough about woodworking to read this article, you can save up $49 for a good starter orbital. If you plan to do this regularly as a hobby, a profession, or if you just like having the best tool for the job. I highly recommend spending an uncomfortable amount of money on this Festool sander. Oh, and you are also going to need a Festool vacuum to keep the lungs clean too. I literally laughed out loud at the $500 price tag for a sander when I first saw how much they cost. Then $700 for a vacuum almost made me quit woodworking. Now I own three Festool sanders. Just one vacuum though. You really don’t realize how good they are till you try.
If you are still reading this, excellent! I haven’t scared you off. The rest of the tools and materials are much more reasonable, I promise. Great sandpaper is just as important as a great sander. Think of it like putting cheap tires on sports car. To prove this is isn’t Festool sponsored article, as some of you might think. I actually don’t care for the Festool sandpaper nearly as much as the Klingspor paper. Also, Klingspor paper is about half the cost of Festool paper. Klingspor even makes paper to match your Festool sander.
Depending on what you are finishing, I recommend two different finishes. Both made by Osmo. The 3043 is the only finish I’d recommend for a resin and wood table. However, I prefer the 3054 for solid wood tables. For both of those top coats, I recommend sealing with the Osmo 1101 thin first.
Lastly, you’ll need something to buff these in with. I’ll go into more detail below, but you can use your orbital sander to buff with. However, if you’re a real tool junkie, go ahead and add the 11” Gem orbital sander/buffer to the list. That’s what I use.
Step one
I add a pencil grid every grit up to 180
We are going to begin our process assuming we are starting with a nice flat piece of wood. For our examples I’ll refer to it as a table. This table could have come straight off the planer, the belt/drum sander, CNC, or shop made router sled.
I start by drawing a pencil grid on your table. Don’t push crazy hard, you don’t want to dent the wood. You just want to cover the table in a grid to track where you have sanded and where you haven’t.
Step two
Now we are finally ready to start making some dust! We are going to run through all the grits. And by all the grits, I mean, 100, 120, 150, 180, 240, 320. A lot of you might be wondering why you can’t just go 100, 150, 240, or some similar grit skipping combination. These grits are specifically designed to remove the scratches from the grit that comes before. So if you go from 100 to 150, you will be left with tiny scratches that might not become visible until you finish. By then its too late, and you’d have to start all over. Message being, don’t skip grits. Some of you won’t listen, and that’s fine. I did the same thing. But if you want a truly professional finish, try and come around sooner than later.
When you sand wood and resin, try and keep the sander moving all the time. The harder resin sands slower than the wood. So it is very easy to get a distinct lip where they meet. The same can happen with highly figured woods. Especially figured softwoods like curly Redwood. One bonus to the festool sanders is that you can get ultra soft, soft, and firm pads. A firm pad with help with this, but really try and keep that sander moving. If you are also using the Festool vac, they do suggest turning the suction all the way down. It is supposed to help with getting a cleaner sanding pattern. However, I haven’t been able to tell a difference either way.
Sand resin for 1-2 seconds before cleaning
Another great trick when sanding wood and resin, is to keep a microfiber towel handy. As you sand the resin, it likes to clog the sandpaper pretty fast. Once its clogged, it will leave little “pig tail” swirls in your resin that must be removed before moving to the next grit. Use your microfiber towel to wipe away the resin dust every two seconds or so. This will greatly cut down on the pig tails. Also, a shot of compressed air can dislodge the clogged dust from the disk.
If it sounds like this process takes a long time. You are paying attention. Sanding is the worst part of woodworking. Its loud, dusty (not as bad with a vac), tedious, and you really don’t see a lot for your work. Unfortunately, if you skimp out here, all your fine craftsmanship will be for nothing. To be clear, I am NOT the old timey woodworker that will tell you have to do something that isn’t absolutely necessary. I use jigs, power tools, CNC machines, and anything that can get my product done better, faster. Not to say I don’t enjoy the process of old timey craftsmanship. This just isn’t that type of article. This is how you can get a perfect finish with the best tools you can afford, in your garage or shop.
I sand all the way to 320 grit. Which is the highest that Osmo recommends. The lower the grit, the more finish is allowed to be absorbed. Therefore, the more protection your table will have. For a solid wood table, you could stop as low as 150 grit in my opinion. At this grit the sheen will be much more matte, and any figure will not really pop. As you move up, the sheen will move up slightly with each grit. The grain, color, and figure will also increase with every step up. 220/240 is a totally acceptable stopping place, however I find some of the tiny sanding scratches are still barely visible with resin tables. That is why I go all the way to 320.
Step three
Brushing in the 1101
I actually love applying the finish as much as I hate sanding. This is the exact opposite of sanding. In just a few seconds, you get to see all your hard work come to life. There are a couple of ways your can apply the first coat. This step is not nearly as critical to follow to the letter as the sanding. The important thing is to get the entire piece covered, let it soak in, then wipe it all off.
The main purpose of using the 1101, is that is provides an increased level of protection from stains and water marks vs using only the 3043 or 3054. Since the 1101 is so thin, it really soaks into the wood. That is why I have started brushing it on. I used to buff in with a white pad, but I feel I can get a little more finish absorbed with the brush. After you paint the top, go ahead and flip the piece over (yes still wet). Repeat the process on the back and sides. Let the finish soak in for 10 minutes or so, then wipe thoroughly with clean shop rags or blue shop paper towels. The reason you finish both sides at once, is because of wood movement. If you finish one side and plan on finishing the other the next day, the one unsealed side can absorb moisture from the air and cause the piece to cup. It has actually happened to me in the past, don’t let it happen to you. Since walnut is an opened grained wood I apply two coats of the 1101, waiting a day between coats. One coat may be sufficient for your project though. No sanding is necessary between coats of 1101.
Step four
3054:
Now you are ready for the topcoat. I’ll discuss the 3054 first. Which is my go to finish for any wood piece without a large amount of resin. There is no sanding necessary when applying 3054 or 3043 over the 1101.
My preferred application tool is a bondo spreader. I just pour some osmo on and spread it out with my spreader.
Once it is on there, you need to work it in with a red pad. Pretty thoroughly. You can do it with your hand, but it will tire you out. You need to really aggressively work it in. You want to build up some heat if you can. A better option is to cut a square out, set your orbital on the pad, and turn it on. Press down hard, letting the sander do the work. If you have one of the Gem buffers, they are definitely the way to go.
After you feel you have the entire piece very well buffed in, wipe the piece very well with blue shop rags. You want to remove every last bit of the finish at this point. You should note that it is ok to finish one side at time with the 3054. Opposed to the 1101. Since both sides are already sealed, no need to worry about about the wood cupping.
Wait overnight, sand lightly with 400 grit on your orbital sander, and repeat the process. I generally add two coats of 3054. Sometimes three if I want a little extra sheen.
3043:
The process is actually a bit different between these two finishes. It starts the same, by spreading the 3043 on the table, just like the 3054. The next step is to buff the finish in with a white pad (instead of red pad). I use my Gem buffer and buff and buff and buff until it doesn’t look like any more finish can be absorbed. This usually takes 10 minutes or so. Note: you can also use an orbital sander for this step. After you have it good and buffed, go ahead and flip your pad over to the clean side, and start buffing again. You want to buff until you don’t see a single streak. The sheen might look a little uneven at this point, and that is ok. You just want to get all the Osmo streaks removed with the white pad.
After you let the finish cure overnight, come back and sand lightly with 600-1000 grit. The higher the grit you sand with, the higher your sheen will end up. I generally sand with 600 grit for a nice satin sheen. Once it is sanded, go ahead and repeat the finish process as before. Using your buffer or orbital sander.
Each coat you add will add more sheen. Two coats is sufficient for protection, however you can feel free to add more coats if you’d like more sheen.
Additional tips/notes
As easy as Osmo is to use, I’ve run into problems with fingerprints in the finish. Turns out, you really need to not handle your piece (with bare hands) for about a week after finishing. Furthermore, you want to wait at least three weeks before really testing out its durability with food and water stains. Their liquid wax cleaner works well to clean up and it even rejuvenates the finish at the same time.
People often ask about the underside of my tables. There is no need to get the bottom quite as nice as the top. I sand the underside to 150. Apply one coat of 1101, one coat of 3043 or 3054 and call it done. If you have a clear resin table, you may opt to sand higher to step up the clarity though.
Unlike a film forming finish (poly/varnish/lacquer), Osmo can be spot repaired. So if you get a scratch from a dropped tray for example, you can just add a little more finish, wipe it off and it will be all but invisible. Touch ups do take a little practice. Just start small and work up. Try no sanding, just finish at first, then get more aggressive as needed from there.
That’s it! you are all ready to step your finish game up to professional level. If you have more questions, don’t hesitate to check out my Youtube videos. I’m pretty good about answering questions left in the comments there if I left anything out.