Advanced sanding?

The Achilles' Heel of Luthiery
deadedith

Advanced sanding?

Post by deadedith »

Ok, I maybe need some instruction, going back to basics.
John, you mentioned that you never go beyond 220 grit.
At 220, no matter how diligent I am, using the best paper I can get my hands on, if I wet down the wood I will see many tiny scratches.
I usually have to go to 600 or 800 for any satisfaction.
What am I doing wrong?
DaveB
tippie53
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Re: Advanced sanding?

Post by tippie53 »

that won't show up . You are giving the material to bite into. If you make the surface too fine the finish won't hold . The tiny scratches you see will hide under the filling and finish.
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
deadedith

Re: Advanced sanding?

Post by deadedith »

That's good to hear. Thank you John!
DaveB
Haggis

Re: Advanced sanding?

Post by Haggis »

Do you sand the body with 120 grit => 180 grit => 220?
Would that be good enough?
/Häggis
nehsgolfer
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Joined: Tue Mar 11, 2008 9:09 am

Re: Advanced sanding?

Post by nehsgolfer »

I have a (dumb) question to ask. I don't know a lot about wood, but rosewood, mahagony, etc. are very porous, I know. How deep do the pores go into the wood?? Could you sand enough to get below the bottom of the pores to where the wood is smooth and not have to pore fill???
deadedith

Re: Advanced sanding?

Post by deadedith »

Haggis - a good 120-150-180-220 sanding will do the job. You can go higher with some finishes - with the Tru-Oil I go up to 1200 or higher - but 220 will give a dazzling finish with nitro and other finishes.
Always do a test run on a piece of scrap. You don't want to be guessing and saying "I hope this works" - you want to KNOW that it will work, when you start on your instrument.

Golfer - look on the inside of your back and sides. Pores. The dang things do not go away.
tippie53
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Re: Advanced sanding?

Post by tippie53 »

pores in the wood are continuous and you can't sand them smooth. They do need to be filled
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
JRHall
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Location: Columbia, South Carolina

Re: Advanced sanding?

Post by JRHall »

The pores disappear when you come out the other side.
If you can't do something well, learn to enjoy doing it poorly.
naccoachbob
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Location: Nacogdoches, Tx

Re: Advanced sanding?

Post by naccoachbob »

nehsgolfer wrote:I have a (dumb) question to ask. I don't know a lot about wood, but rosewood, mahagony, etc. are very porous, I know. How deep do the pores go into the wood?? Could you sand enough to get below the bottom of the pores to where the wood is smooth and not have to pore fill???
The pores run in and out and up and down in the wood. They are not on one static surface, so you can't get "below" them.
Woody OKeefe

Re: Advanced sanding?

Post by Woody OKeefe »

I disagree,

Pores do not need to be filled. It is a personal choice which does not affect the tone of the guitar. The pores are a natural part of wood and filling them with various substances is not necessary. I get a smooth and (according to John Hall) shiny finish and I am happy with that. Bob Taylor said something like. .. If I could fine the guy who came up with pore fill and a gloss (or glass) finish I would shoot him.

Just my .02
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