Can wood be sanded too much?

[Chuck Darney]

I'm doing a project with tiger maple. I used a test piece of wood with some Zinsser's shellac and it looked very good. When I applied it to the project, though, the grain doesn't stand out as well. The only difference I could imagine is that I didn't sand the test piece as well. On the project I sanded down to 220...lots. If this is the case, could I "rough up" the project with some 150 or 100 grit then apply more shellac? I would then sand with 220 between coats.

Thanks...Chuck

[Joe Leigh]

The best way I found to make the figure pop is to use an anyline dye. Jeff Jewitt has a great article on this technique on FWW. I used a water soluable dye which raises the grain. Just sand again till the tone is right and BLO or straight shellac and you'll see a big difference.

[Darrell Bade]

IMO - yes it can be sanded to much. I used to sand to 220 with a ROS until I made a nightstand out of White Oak and it would not hardly take a stain. Now with Red or White Oak I stop at 180 with a ROS and it seems to take a stain better and still has a nice finish.

[Jason Beam]

yes - but not usually with 220 ... as you use a piece of sandpaper, it's effective grit gets smaller and smaller. You may start with 220, but if you go at it for 40 minutes, it may be effectively 400 grit by then - which CAN be too much for some finishes to penetrate well.

But ... i'm more inclined to bet you just have two different pieces of wood that have differen't characteristics. Some boards will pop more than others.

[Chuck Darney]

The test piece I used was a cutoff from the project so it's the same wood. I can believe that the 220 was much finer as I worked with it. I think I'll just run over it with some lower grit (new paper on the ROS) then reapply the shellac.


yes - but not usually with 220 ... as you use a piece of sandpaper, it's effective grit gets smaller and smaller. You may start with 220, but if you go at it for 40 minutes, it may be effectively 400 grit by then - which CAN be too much for some finishes to penetrate well.

But ... i'm more inclined to bet you just have two different pieces of wood that have differen't characteristics. Some boards will pop more than others.

[Faust M. Ruggiero]

If you want to pop the grain using an oil finish, don't sand past 150 grit. The whole idea is to get as much oil as possible to soak into the wood. The finer you sand the less fibers are left on the surface to act as wicks. Back off to 150 grit hand sanded with the grain and let the oil soak in a while before beginning ro rub it off. You will like the results.
Remember, as long as you let most oils dry completely, you can still top coat with lacquer.
butch

[Chuck Darney]

Thanks for the help and suggestions. I ended up sanding down to 100 grit then lightly with 150 and 220. It helped quite a bit. I never did get quite the look I wanted but I'll know better next time. Since I'm pretty new at this, here are my lessons learned:

1. Don't oversand!
2. It's not as easy to finish work when the humidity is running at 98%.
3. Keep the finish out of the holes drilled for the shelf support - especially if you can't get a drill in the area to clean them out.
4. Mirrors DON'T like screws.
5. Make the rabbets wider if there's room.

Here's the result (sans large glass shelves). The case is ply wrapped and edged in tiger maple. The door is solid tiger maple with mirror on both sides. The splines are walnut. The entire case is 30 1/2" wide by 35 1/2" tall. The side shelves are 6" with a mirror back.

Thanks again...Chuck

[Howard Acheson]

Here is something that may be helpful:

Sanding wood--hard or soft--beyond 220 does little more than burnish the wood making staining difficult. This is particularly true if you are using a pigment stain which sits on the surface and relies on "nooks and crannies" to impart color. Softer more porous woods can be sanded to to 220 but harder less absorbent woods may stain best if only sanded to 150. The best compromise is to aim for 180 grit.

A number of years ago a large cabinet/custom furniture shop I was involved with did series of adhesion tests with various finishes and sealers. As part of this test we explored adhesion based on sanding grit. We found about the same adhesion up to 180 - 220. Beyond 220 adhesion dropped off due to burnishing of the underlying wood particularly when non-linear machine sanders were used. This was tested on birch panels. We also found that the resulting smoothness of the first coat of finish was not materially affected by the smoothnes of the underlying wood for sandpaper grits between 150 - 220.. The smoothest surface substrate for final finishes was obtained by sanding lightly after the first coat of finish was applied and dry. Which makes the case for a thinned first coat of finish.

So our conclusion was that sanding beyond 180-220 was not necessary and could be actually detrimental.

But, most important was that there was a big appearance affect if the surface was not HAND sanded in the direction of the grain using the highest grit used on the sanding machine. A flat pad sander produced a much flatter surface than a ROS. However, both required final hand sanding with the grain for optimum appearence. If not hand sanded, swirl scratches could show. Final hand sanding using a sanding pad in the direction of the grain is a must.

To carry it one step further, sanding at 320-400 grit after the first coat and subsequent coats was the optimum. No improved appearence was noticed by between coat sanding beyond 400 for varnish. 400 was the sweet spot for thinner finishes. Between coat sanding was always done by hand whether for flattening or for adhesion.

I think you will find similar thoughts in the popular finishing books but YMMV.

Finally, the first coat of ANY finish will soak little shards of wood and cause them to raise whether the surface was sanded, planed or scraped. When the first coat of finish dries these hardened shards are what causes the surface to feel rough. Sanding with 320 paper will remove these hardened shards and subsequent coats will go on smoother. So, smoothness counts after the first coat of finish, but not much before that.

The machine finish determines the starting grit. Jointers, planers, belt sanders etc, should leave a finish that allows starting with 100 grit. From there, go to 120 grit and sand until the marks from the prior grit are gone, then move to 150 and finish at 180 grit.

Plywood is factory sanded to 180 grit. Therefore, it's best to not sand plywood except with 180 grit and sand by hand. Get the first coat of finish on and then sand with 320. That way you are sanding the finish, not the wood. This avoids sanding through today's very thin surface veneer.

[Prashun Patel]

Howard,

That's a fantastic account and clears up a lot of questions/misconceptions I've had. Thanks for posting.

What about for in-the-wood finishes? When I apply O/V blends I've noticed the wood feel seems to improve when I wetsand latter coats in with 600, 800, and 1000gt. The wood seems to get silky.

I assume this is burnishing, and that it does not adversely affect the O/V's penetration which happens largely during the 1st couple coats at lower grits. Right?

[Joe Jensen]

I have very strong opinions about finishing woods like tiger maple. Many say to use Boiled Linseed oil or dye or stain to make the figure "POP". POP means different things to different people. If you are using just shellac, I assume you don't want to color the wood. Here is a pic of jewelry boxes of curly maple with just shellac.

http://i174.photobucket.com/albums/w99/AZEngineer/JewelryBox5small.jpg

Finished this way, the grain exhibits a lot of chatoyance, where the light and dark areas move with the angle light hits the wood. This is what I like. If you want to have this property maximized, never use stain, and pentrating oils will reduce the effect. Surface finishes work best, and if you must color the wood, use dye only.

POP for others means having maximum contrast in the figure. They use finishing that absorbs more into parts of the grain. This approach highlights the figure, but in the end there is little Chatoyance.