Turning Archive 2005

Subject:
Discussion fodder - sanding to high grits (long)

Mike Schwing from Md.
>Many of you know that I am fond of sanding my display pieces to very high grits. When I post my sanding/finishing regimen, someone invariably asks why. A very reasonable question! I thought this would be a good topic for discussion here and would like to ask for your participation, if you have an opinion or observation you feel comfortable sharing.

First, what is a high grit? For this discussion, let's make it anything higher than P600, since this is probably close to the finest paper many turners ever use. Really high? 4000 on the P scale or 12,000 Micro Mesh.

As a child, every year I watched my father sand the brightwork, usually mahogany, on his boat to 1500 before applying a finish. His brightwork was by far and wide the highest quality of any you could find, and he won many awards. Sanding so high brought out the grain like nothing else, so much so that it caused a dramatic reaction from a viewer when compared to something sanded to much less fine a grit. It also prepared the surface for applying a building finish, closing pores and creating such a fine surface that more light reflected off of it back through the finish - true "brightwork". I learned to do the same to the wood on my little Boston Whaler, and then on a pair of Cypress Gardens water skis, and so on, and so on...

So when I started really woodworking, I already knew the "finish goes on before the finish goes on" routine. I also have many years experience in an auto body shop, where sanding is at least as important. So thats it for the background.

Now for woodturning. Sanding to a high grit reveals more of what is underneath that finely sanded surface. That includes any sanding defects from previous grits. Extreme, fanatical attention to sanding detail is needed on the heavier grits, or they will show right through your nicely sanded P600 surface. Move that up to P4000 and you've got really noticeable sanding scratches. It takes a lot of time to do this, which is a definite drawback. If I can sand a piece to 320 in 30 minutes, it might take me 3 hours to bring it up to P4000 with no defects visible. I still think it is worthwhile, because I know it is the best I am capable of producing.

Try this for yourself. Take a board and sand a section to 320, then a section to 600, then 1500 or even go up higher. Put a coat of wax or watco on it. Buff it dry. See the HUGE difference? (of course you do)

Sanding like this on bare wood is no different than sanding out a lacquered finish to produce a high gloss or sheen. Do both and you'll have a workpiece that will stun viewers.

Besides making the grain stand out in ways simply not possible with rougher grits, the finish goes on easier, takes fewer coats, and shines better as well. Why? Finely sanding a surface has the effect of closing the pores or almost burnishing the wood. Don't believe me? Put a piece of thin, unsanded wood on a vac drum. Notice the gauge reading. Turn off the vacuum. Sand that board to a high grit, then blow or brush away any dust. Turn the vac on again. Note the huge improvement in vacuum draw. So with a surface thusly applied, the finish does not sink in to the wood. Yes, Watco and other drying oils harden inside the wood, perhaps making a more durable piece, but my goal is to finish a display piece with a visible finish. I don't really care about it soaking in. Also, finishes shine because they reflect light back to your eye. A finely sanded surface shines on its own, adding to the light reflection going back through the finish to your eye, making your piece look even better.

People will say that finishes won't stick to finely sanded surfaces. Every time someone says that I ask them to provide any scientific proof. I'm happy to change my opinion when provided with proof. So far - none.

I use two different types of fine grit paper - Micro Mesh and more recently Abralon pads. The Micro Mesh has smaller jumps in between grits, and therefore, I believe produces a better surface. But the soft backed Abralon pads (http://turningwood.com/) go much much faster and produce a beautiful, just gorgeous finish. The Micro Mesh seems to last longer, but the Abralon is much less expensive.

Is this method applicable to all turnings? Not in my opinion. A utility piece will quickly become scratched and ugly if finished in such fashion. Much better, IMO, to finish a utility piece up to 220, maybe 320. But display work - you bet I think it is worth it. Examine the bowl in the "Sorry Jamie" post - look at the grain and tell me if you can get that look with 220 or 320.

These are just my opinions, and obviously I have written this as a "pro" high grit opinion. I don't wish or need to convince anyone but I sure would love to hear your opinions and what you do similarly or differently. Thanks!

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