Do I actually need grain filler for a refin?

Discussion in 'Luthier's Corner' started by LordOrange, Jun 12, 2021.

  1. LordOrange


    Mar 10, 2020
    To start, I'm a total newbie to refinishing etc.

    I've had it in my head for months now to strip the cherry poly finish off of my old Epiphone EB0 and refinish it with a can of Northwest Guitars Nitro white lacquer. It'll just be a fun project and I don't really need to worry about ruining the bass, as I've since upgraded to a Gibson EB3, as well as a couple of other basses.

    I want to get started. I bought a big tub of multi-purpose wood grain filler back in February. However, I am not sure whether this is necessary. If I were to sand off the finish down to the wood, do I still need to apply the grain filler after? I've heard some people say no you don't need it, and some say that you do need it. I want a gloss finish at the end.

    Hoping some clever folks in here can give me some guidance.

  2. Bruce Johnson

    Bruce Johnson Gold Supporting Member Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    That depends on how thoroughly you "strip" the poly finish off of there. The grain is already filled under the poly finish. It's possible to get all of the old finish off of there, including the grain filler, but that's a whole lot of work. You have to actually sand away some of the wood. And why bother to do it, if you want a smooth gloss white finish? You'd have to re-fill the grain.

    The existing poly finish can be a good solid base that you can repaint over. I would just sand the existing finish up to 600 grit, dry, making sure it's smooth. Don't go any finer than that. You want to get a good bond to the Nitro.

    When it's all looking good and smooth at 600, clean it thoroughly and start spraying on the white lacquer. It may take 6-10 coats to build it up thick enough to be opaque bright white (if that's what you are going for). Hopefully, it's laying down fairly smooth; not too much roughness or orange peel. Let it cure for several weeks, then wet sand it smooth with 1000 grit, up to 2000 grit. Then buff it out to a high gloss.

    For a solid color like white, there's no need for clear coats over the white color coats. Just build up the color coats up to be thick enough that any roughness can be sanded out without going through. If you do sand through, back up and spray some more white.
    Last edited: Jun 13, 2021
    Joshua, Beej, LordOrange and 3 others like this.
  3. LordOrange


    Mar 10, 2020
    Thanks very much for your response. This is just what I was looking for!