I'm starting a project to build my own solid body guitar.

I received the body and its made from ash. It needs to be filled (the grain is very porous).

I hear that I need wood filler for this.

The plan is to stain the guitar with a walnut stain and then finish with an oil finish (no lacquering and I want the grain to show through).

So my questions are, does it matter what wood filler I get? and all wood filler can be stained, right?

I've heard that a darker wood filler will accentuate the grain and give a greater contrast between the areas of the grain. However, I also had some advice that I should fill the wood in a similar colour and stain over the top.

I'm quite confused and don't want to get it wrong. I would like the grain to show up as much as possible, but don't want to ruin the staining by putting the wrong filler on it.

  • There are wood fillers that are specifically made for opened grain wood, as opposed to hardening fillers made for structural purposes. Check out constantines.com
    – bib
    Jul 18, 2012 at 15:27
  • Ah, you see this is what I need to know. How can you tell the difference? I'll be off to B&Q later... Is this what I need? diy.com/nav/decor/decorating-sundries/fillers-putty/… or something like this? diy.com/nav/decor/decorating-sundries/fillers-putty/… Jul 18, 2012 at 15:44
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    By "filler", do you mean a sealer? Wood filler (as I understand it) is a putty-like substance that's used for filling e.g. nail holes or other damage, whereas a sealer helps stains to stain more evenly by preventing it from soaking in as much. Also, if the acoustic properties of the finish are important, music.stackexchange.com might be a better place to ask this (at least, they have appropriate tags: guitar and construction).
    – Niall C.
    Jul 18, 2012 at 15:47
  • I'm not too worried about the "acoustic properties" as its going to be an electric guitar and the pickups and amp will be doing most of the work there. :) By filler, I'm not really sure. Basically where there is grain there are loads of pores, so I want to get it smooth before staining and finishing. But I don't want to fill it with something that a) can't be stained and b) will damage the wood. Jul 18, 2012 at 15:57

1 Answer 1


Wood fillers for filling grain are very different from those used for structural repairs. Grain fillers are diluted and rubbed into the wood grain. See the attached listing from Constantines, one of the leading woodworking suppliers in the U.S.:


They are also a source of components and books on building guitars.

I do not know of a non-U.S. source, but they may ship internationally and their info may help evaluate local resources you find.

  • Is Rustin's a reasonable alternative to constantines? Apparently you mix with white spirit to thin it. Can I stain over it? Or should I mix the stain with the grain filler? Jul 18, 2012 at 16:14
  • Not familiar with that product. Many fillers have a plasticizer in them which prevents staining. When something will accept stain, it almost always says so.
    – bib
    Jul 18, 2012 at 16:25

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