Flat-sanding a guitar fingerboard

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Issue 219 June 19, 2014

Dan Erlewine has a quick tip for sanding anything truly flat. He demonstrates with a guitar neck and fingerboard that he's prepping for glue-up.

In this Trade Secrets video:
  • How to prep two wooden surfaces for glue-up
  • Truly flat, square block is an easy-to-make shop essential
  • Pencil scribbles indicate sanding progress
  • Pre-cleaning with Behkol solvent

Video Transcription

[on-screen text reads: Stewart-MacDonald - Trade Secrets!]

Dan Erlewine: I'm making an electric guitar here and I haven't worked on it for months and I'm getting ready to join the fingerboard to the neck and since it sat around so long, the wood is oxidized, picks up dirt and the pores kind of close up, and I need to flatten them and clean both surfaces. And I'm going to do all that on this block of wood.

A truly flat square sanding block

It's a neck blank [on-screen text reads: Electric Guitar Necks and Neck Wood at StewMac] that I've made dead flat on all sides on my joiner, squared them up to each other, and I use this in a lot of ways. I'll use it on a drill press, or a milling machine, to hold the body or a neck for machining operations. And I use it a lot for a sanding block and that's what I'm doing now.

Pre-cleaning with Behkol solvent

I'll wipe the wood with some acetone or some Behkol alcohol solvent. I want to get rid of any little spots of glue, if they come out. If they don't, I'm not worried about it. Probably the pencil line will go. So I'm going to get them clean and I'm just putting a little bit of pencil across it. That's how I follow my sanding.

Sanding the fingerboard

I'll put 220 grit gold sandpaper on this from end-to-end and I'll true up the surfaces of the fretboard and the neck, stroking it back and forth lengthwise, until my pencil marks that I put on the back are gone. And that opens the pores of the wood and gets them ready to be glued up and they'll be dead flat. You can see where it's working on the light wood. It's happening really quickly too.

That's a final sanding. The pencil marks are gone. I used a razor blade to pick up any fur and fuzz and it's dead flat. One last wipe with Behkol to really clean it and this is ready to glue on to the neck.

Next, I'll do the same thing to the neck and these pieces are ready to be glued together.



Dan Erlewine

Guitar Repairman and Builder

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