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Just came across this posting by "the maestro" Frank Ford on the AG Luthiers Forum:

"By the way, you DO sand spruce across the grain, yes?

Block sanding with fine grits across the grain reduces the tendency to scar and dig out the soft grain between the hard lines, and results in a finer, flatter surface. Scratches from fine cross grain sanding don't show in spruce. If you haven't - give it a try. . . "

This is definitely in the learn something completely new category for me. Any of you OLF'ers already do this?

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

This is propably true with 320-400 and higher but would not try this with 220 or lower. The depth of the scratches would cause an issue I would think. I have and will continue to sand raw wood with the grain. It is just what I was tought from my grandfather.

Oh, yeah, Dave, I started doing it this way about two minutes ago!

Makes sense for something as soft as spruce with that hard grain part. I'll surely give it a try.

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now known around here as Pat Foster
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http://www.patfosterguitars.com

I have found that using a wooden sanding block with, say, 220 grit paper and sanding against the grain is really the only way to get rid of the ridges that tend to accumulate because of the grain lines. I don't do this on the whole top, though, just the spots where the ridges appear, which are usually on the edges of the top, and often the result of scraping/sanding down binding and purfling.

Best,

Michael

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Live to Play, Play to Live

I've read that any scratches that do show from this cross-grain technique look like "silking" under finish. Again, that's only what I've read, not from personal experience; but apparently some people do this just for that effect.

Cool! This has had me befuddled for some time! I'm gonna try this as soon as I get home!

-Mark

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Pullman, WA

The more I know, the more I know I don't know.

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Good timing Dave,
I have just closed the box on my latest and will be pondering just such things as this.
Good one.
Thanks,

Wade

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Wade
Nashua, NH
http://www.wadefx.com

I've found that sanding across or at least at an angle to the spruce grain works much better also in the recurve areas of an archtop. I do this when a little material removal is needed but usually end up going with the grain when final sanding (220 grit) prior to applying finish. Seems like some of the same factors may apply here as when feeding a workpiece thru a drum or belt sander at an angle?
Scraping soft wood such as spruce sometimes works better if done at an angle also to avoid tearout.
Nelson

I just tried this on a dread I'm getting ready to finish, and lo and behold, it works! Another obstacle overcome!

-Mark

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Pullman, WA

The more I know, the more I know I don't know.

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You know, John Watkins turned me on to this idea. His theory, and it makes total sense, is that if you are going up in grits, it won't matter if you have cross grained scratches because you'll work them out with the next grit.
It's worked out pretty well for me.