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Hi,

Is using 400 grit sandpaper too fine a grit for finishing the guitar wood? I guess what I am getting at does it close off the wood so the stain doesn't penetrate as well or does make any difference at all ?

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Dean

Yes that is too fine. It can close off the wood fibers so the stain doesn't penetrate and lays more on the surface causing adhesion problems with the finish. Even without stain that is too fine, the finish needs a surface texture to grab hold of or it can delaminate or peel. I never sand past 220 prior to applying any finish materials and in most cases only to 180. I go to 220 on spruce and other woods that do not need a pore fill and 180 on the rest.

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Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

For sitka spruce I go up to 400 grit hand sanded. It brings out the silk figure found in most Sitka. I sunburst many of my builds and so far 400 grit hasn't caused any problem with water based dyes. As always test results on a piece of scrap wood first!

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http://www.cushmanguitars.com/.

A man who carries a cat by the tail learns something he can learn in no other way.
Mark Twain

The exception to what Brian says above is TruOil and similar hand applied oil varnishes. I've sanded spruce, curly maple, and bloodwood to 800 grit with no adhension issues. Going that smooth really brings out any silk or figure.

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A man hears what he wants to hear, and disreguards the rest. Paul Simon

Thanks Brian!

What about Mahogany, it seems fairly tight grained to me? Would I use something in the range of 120-180 grit?

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Dean

I go to 180 on Mahogany. This is based on hand sanding and not by machine. Sanders seem to burnish the wood a bit more and I would stop at 150 if using one on mahogany.

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Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

I usually sand to 400 by hand if I am staining a mahogany neck. If i stain over agressive scratches, they can become even more obvious. Everything else goes to 320. I see sand scratches in the wood after finish if sanded less than 320. I agree with what others say about the silking in spruce, 320 to 400 allows it to have an "iridescent" appearance that the lower, more agressively grits seem break up and disguise. No adhesion issues for me.

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jw ( o)===:::

I am hand sanding. I guess I will head to home depot and pick up some 180 LOL...

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Dean

I used a scraper to get the corner rounding that I wanted and of course the klutz that I am I slipped a couple times. I had one really bad gouge on the top and I had to level sand it with 120 to get it out. I could kick myself in the arse. Eh, live and learn...

I had put a black stain on to highlight the grain and discovered that I had screwed up the sides and there were not perpendicular to the top and back. So I had to throw it back on the spindle sander to fix that. Then I went to work with the scrapers working on the edges.

Oh forgot to mention, I am talking electric guitar body. Here it is just before I gouged it... Its a strat (obviously) that I modified a bit to be narrower...

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Dean

One exception to the 180g recommendation is on the end grain of most hardwoods and Pine. You can use the burnishing effects of 400g to slow the absorption of dye and stain which will help it from turning much darker than the face grain surface.