Know Your Terminology

If you understand sandpaper lingo, you’ll find it much easier to choose the right material for your work. That means you’ll get the job done faster, you won’t waste as much paper, and the results will be better. First let’s talk about the grit types:

Aluminum Oxide: This is the most common material used for woodworking. Its very durable and lasts a long time because it is friable. That means as you use it, the grit breaks apart and leaves more sharp edges. So the paper sands consistently and lasts longer. You can use this stuff on more than just wood and you’ll see it used for sanding finishes, plastics, metal and paint.

Garnet: Garnet is a natural abrasive and it is generally only used to sand wood. The reason is because it is NOT friable. Instead, the grit wears down as you use it and ultimately leaves the wood with a smoother surface than aluminum oxide sandpaper. But I get such good results with my standard aluminum oxide papers, I don’t really bother much with garnet.

Ceramic: I don’t even have any of this stuff in the shop. Its very hard and durable and generally used for aggressive stock or paint removal. Common to see these in more aggressive tools like belt sanders.

Silicon Carbide: Easy to spot because of the color (Gray or black). As woodworkers, these are great for sanding and polishing finishes. They have super high grits and can be used wet or dry, so when we talk about we-sanding, this is the stuff we’re using.

Stearated: You’ll very frequently hear the term “stearated” being used in reference to sand paper. Basically, this is a chemical treatment that prevents the paper from clogging. Think of it like a coating of soap that stops wood and finish from adhering to the grit. So stearated papers are great for sanding finishes, because the finish dust tends to ball up and stick to the paper.

Closed vs Open Coat: This property refers to the amount of space between the grit particles on the paper. Open coat means the grit is further apart and is less prone to clogging. It also means the paper tends to last a little longer. Closed coat means the grit particles are closer together and the paper can become clogged more easily.

Armed with this terminology, you should be able look at any package of sandpaper and determine how you might be able to use it and whether it is appropriate for your project.

Don’t Skip Grits

Sanding is nothing more than scratching a surface with grit, right? And its pretty obvious that 80 grit scratches are much deeper than 220 grit scratches. So if you jump from 80 to 220, you’re asking a lot of that 220 grit. In fact, you’ll work harder and go through a lot more paper if you try to remove 80 grit scratches with 220 grit. So it is much more efficient to jump from 80 to 120, and then to 220. Not only will you save time, but you won’t go through quite as much paper in the process. Additionally, you’ll have a much smoother/consistent surface in the end.

Use The Right Pad

This is something we don’t talk about much because most sanders only have one pad available. But did you know that the pad itself can have an impact on your sanding results? For most large or perfectly flat surfaces, you can reach your desired surface finish pretty effectively using a soft pad.
For more delicate pieces, curves or contours, you?re going to want to use a super-soft pad.
For the most delicate of surfaces, or sensitive of curves, you can even employ a cushioned interface pad that eliminates any pressure so you lightly abrade the surface while maintaining a precise shape or profile.
For jobs where a crisp edges are essential, a hard pad would be idea. For instance, when you’re sanding a fairly narrow edge, a soft pad will round over the edges very quickly. But a hard pad keeps the the edge square and doesn’t conform to the edge.

Festool has pads for all of these situations, including a special long life pad that is resistant to high temperatures. Excessive heat can actually destroy the plastic hook and loop material so in a heavy-use or industrial setting, a long life pad can really save you some headache.

Use Dust Collection

Most of you should know that the dust created by sanding is incredibly bad for you. I try to hammer this home every year during safety week. The best way to avoid breathing the stuff is to prevent it from getting into the air in the first place. So the way we do that is by effectively collecting the dust at the source. When you buy a sander, you should absolutely keep an eye out for a dust collection port and instead of just using the collection bag, connect it to a dust extractor.

Aside from heath, there are other potential problems from dust getting in the air. Airborne dust tends to say airborne for a long time. It gets into your tools and eventually, settles into your finish. So if you sand in the morning, you can bet there is still airborne dust floating around when you apply your coats of finish. The end result is more work sanding dust nibs out of your finish.

Now here’s another factor that isn’t discussed very much. You know how when you sharpen your planes and chisels, you have to clean off your chisel after each grit, to prevent contaminating your higher grit stones? The same thing can happen when you’re sanding. Imagine sanding with 80 grit and no dust extraction. The 80 grit dust particles just sit on the surface and can set you back when you begin sanding with the next grit, say 120 grit. The sander is now pushing that 80 grit dust around on the surface and it becomes more difficult to sand efficiently. So if you remove all that 80 grit dust ahead of time, the 120 grit paper is free to do its job.

Parting Tips

• Don’t buy cheap paper. Cheap paper actually costs you more in the long run. Cheap paper and cheap bonding agent means you’ll go through it faster. You want to save $, buy bulk.
• Use a pencil to gauge your progress.
• Sand slowly 1″ per second.
• Don’t tilt the sander.

Looking For More “Down to Earth” Finishing Advice?

Check out my book! Finishing: it ain’t over till it’s over. We even have an ebook version available! Written in an entertaining style with a touch of humor, “Finishing – it ain’t over till it’s over” is designed to provide newcomers as well as seasoned woodworkers with the practical information necessary for a relatively trouble-free finishing experience.

I am new to this woodworking thing. My next project is going to be an entertainment center which will basically be two tall cabinets with doors. The doors will have standard mortise and tenon joints for the rails and stiles. What do you do to the ends of the stiles (where the end grain shows) to make them look good? I have built some doors as a test and the end grain just soaks up the stain and doesn’t look very pleasant. I have similar doors in my kitchen and they look really nice, but they were done professionally. Any help is appreciated.

The Problem With End Grain

End grain is one of those things that can really bite you in the butt if you don’t prep your projects properly. Many times, you finish sanding and everything looks and feels great, but then you apply the finish and all of a sudden your project looks like it was made from two different woods! The end grain soaked up so much finish/stain that it now appears to be a much darker color. Since the end grain is on a different face, where shadows can sometimes play tricks on the eye, you can usually get away with this color discrepancy and few people will ever notice. But there are some areas where this end grain issue is much more obvious, like the top of a rail and stile door frame, and you absolutely must take precautions.

Its All About The Prep

First and foremost, its all about sanding. End grain will always soak up more finish than face grain, and the result will be a darker color. But if you sand it to a higher grit, it tends to burnish the surface and limits the absorption of finish. The result is a lighter color that more closely matches the face grain. So if you plan on sanding the project to 180 grit, I would sand the end grain to about 320. That will greatly improve your results.

But here’s the catch: end grain does not sand as easily or as quickly as face grain. So you might be wondering, “How do I know when I have sanded enough??” Well, if you recall in our recent Keepsake Box project, I explained my system for sanding end grain. Here’s an excerpt for your convenience:

An Alternative to Sanding

Now in some woods, sanding to a higher grit just doesn’t do the trick. Or maybe you are just a little lazy and you don’t want to do the extra sanding. Well there is still hope. Simply pre-seal the end grain. A light coat of a 2lb cut of shellac will work great for this. You can also use a solution of glue size. Glue size is basically a solution of PVA glue and water (dilute the glue by about 90%). Regardless of which solution you use, give the end grain a good sanding after the sealer dries and you’ll be ready for your finish.

“When sanding, I usually sand down to 400 grit. I saw one of your videos where you sand to 180 grit. Am I sanding too much?”

And my response:
Hey Michael. In my opinion, yes. I believe that after 150-180 grit (on most woods), we have a case of diminishing returns. The whole idea with sanding the wood is not necessarily to get it as smmoth as glass. Rather, its to give the wood a clean, even, and scratch-free appearance. To be more accurate, there are always going to be scratches in the surface. But by sanding with the grain, or in a completely random pattern (as with a random orbit sander), your eye will never see them. And the number that I find removes all visible scratches is 180 grit. Sometimes I am even happy with 150, but I usually go to 180 just for good measure. Sanding up to 400 really isn’t going to give you a smoother finish in the end. Because after the first coat of finish is applied, you are no longer dealing with the raw wood. You are dealing with the finish. With sanding between each coat, you’ll have ample opportunity to smooth the surface to your liking. So that’s why I say make the wood look perfect, but don’t worry about it not being glass smooth. That’s what the finish is for. And just as an FYI, I usually increase my grits between each coat of finish. So I sand the bare wood to 180. After the first coat of finish dries, I sand with 320. 400 after the second coat. And 600 between every coat thereafter. On the final coat, depending on the look I am going for, I may buff the surface with 1000 or 2000 grit soft pads. This helps to smooth out any little dust nibs.

Now this is just what works for me. How far do you guys sand your projects?

And this was my response: “Well to put it bluntly, I never use a scraper for final finish preparation. My scrapers are tuned so that they take a pretty aggressive cut, which makes them useful for leveling. But I don’t really like the surface they leave behind when compared to a nice 180 grit sanding. That’s not to say you can’t get a killer finish prep with a well-tuned scraper, its just not my preferred way of doing it. Call me lazy, but I would much rather sit there and let the sander do all the work while I daze off into space and think about whats for dinner.” :) But, I know people that swear by the scrapers and as a result, save money on sandpaper. So there is definitely some merit to it. To each his own I suppose.”

Does anyone out there use scrapers before finishing?

Refinishing Pt. 1
Refinishing Pt. 2
Refinishing Pt. 3
Refinishing Pt. 4
Refinishing Pt. 5
Refinishing Pt. 6