Begun prepping this body for finish: what next?

Discussion in 'Luthier's Corner' started by philthygeezer, Sep 29, 2004.

  1. philthygeezer


    May 22, 2002
    Got this in yesterday:


    I tried sanding at 400 grit to get some of the tool marks out. Too slow. Then went to 320 grit and went a little quicker. Ran the body under the tap and the grain instantly popped up so I sanded it off at 320 wet. There are still a couple of tool scuff marks on the maple top so maybe I wet it down and sand at 320 again? I'm concerned that the body might dry out too much and crack or something. Can this happen?

    So should I sand wet at 320 again or go straight to 400 dry and then 600 grit? I've never done this before. :help:

    I'll be hand-rubbing a Tru Oil finish into this one.
  2. FBB Custom

    FBB Custom TalkBass Pro Commercial User

    Jan 26, 2002
    Owner: FBB Bass Works
    Well, we don't exactly know the condition the body arrived in, but most people start sanding in the 100-150 range and then move to 220 and then 320 before oil. I use 120 to remove tool marks, sometimes 80 if they are deep rasp marks.

    If you want to remove tool marks, you'll want to drop down to 220 at least and skip the water. Then go back to the 320 and 400 if you want it.
  3. philthygeezer


    May 22, 2002
    Thanks much! I dropped to 220 to remove the marks in the alder on the back, and that did it. However the 220 left scratches that are about the same as the ones on the maple top. 320 grit got trid of them OK though. Seems like alder is much softer than maple...

    The scratches on the maple top are barely noticeable and disappear when the body is wet. Will they also disappear with the Tru Oil on it? Is it generally acceptable to have a few tiny scratches left over after sanding?
  4. tjclem

    tjclem Supporting Member Commercial User

    Jun 6, 2004
    Central Florida
    Owner and builder Clementbass
    "Ran the body under the tap " !! Yipe!
  5. Scott French

    Scott French Dude Supporting Member

    May 12, 2004
    Grass Valley, CA
    Yes! A damp paper towel will do!
  6. Next steps for me would be some block sanding from the existing 400 grit to 600. If the grain is really tight and I don't have to worry about snagging, I'll buff with 000 steel wool. Then I would clean the body with naptha and begin the Tru-Oil application. Again, for me, it would be something like 3 coats rubbed in with vigor using a 0000 steel wool pad working with the grain of the wood. A coat would be enough to really get a solid coverage and leave the surface somewhat dry after rubbing. Wipe off the excess oil and let it dry overnight. Repeat this step twice more. What you've done here is pushed oil down into the wood AND worked up a small amount of slurry that has filled any pores that could be there. This should leave you with a very smooth surface and the figure beginning to pop. From there, I use Bounty paper towels to rub in subsequent coats - as many as a dozen or more. After each has set-up but not dry, I buff them slightly with a dry paper towel. Periodically, I'll dry buff with steel wool in between every 2 or 3 coats to keep things smooth but only when it's quite dry so that the wool just makes dust. The oil will build on it's own and as you work in each coat with the paper towels, you will begin to see how you can make a satin or a semi-gloss finish by just altering how hard you apply the coat of oil. Rub in - Buff off, Rub in - Buff off.

    When I get it to my liking, I use a rubbing compound to further buff it and then I wax it with Minwax Paste Wax for wood. I'm very happy with the results.

    I'll post a pic tomorrow of how this techique finishes flame maple. I've recently completed a restoration and this is the finish I used.
  7. philthygeezer


    May 22, 2002
    Heh. I guess that running water over the body may have been overkill. :) I'll just run a damp paper towel over before the final 600 grit sanding.


    1. Do you thin the Tru Oil with mineral spirits, or apply full strenghth?

    2. Do you try to cover the whole side of the body or only a small patch at a time? If in patches, how do you stop it from looking blotchy?
  8. Phil, don't thin the Tru-Oil - it's used undiluted straight from the bottle.

    Great question about how much to do at a time! I break the body into fourths. Front upper horn, Front lower horn, rear upper bout, rear lower bout. As you move from one area to another you'll be able to blend the finish easily.

    I'm headed out to the shop now, I'll have a pic up in a few hours to show you whats possible.
  9. Sorry for the delay...

    When I finally found the camera, it's batteries were dead! :rolleyes:

    I'll try again tonight.
  10. OK, here's the pics I promised...

    This finish has been done with sanding, fine steel wool, a small amount of stain, Tru-Oil and paper-towels. No spraying, just rubbing oil and occasional wetsanding then more rubbing with oil. Final steps were polishing compound and paste wax.

    As good as it might look in the pics, this particular application is WAY off from where it could be taken if I had more patience. I've seen oil finishes that were indistinguishable from a fine lacquer. It will all depend on the amount of time put in on the work. But no matter what, you really can't make a mistake! This is such a slow, deliberate process that a goof can be made in a coat and then corrected within minutes even after drying and the process can proceed again. You can't get drips, runs or gunk in the finish. It won't orange-peel, blush, crack, bubble, or fish-eye. It just gives this nice warm glow.

    If more protection is desired, a fully cured Tru-Oil finish is a good basis for a poly clearcoat. The depth of the figure gets insane. In fact, the wood in these shots would only have been classed as something like AAA flame but with a bit of work popping out the figure, I think it looks a bit better than that.
  11. philthygeezer


    May 22, 2002
    That is beautiful!

    I am nearly done the final 600 grit sanding and am almost ready to start the Tru Oil on a fresh bottle. Instead of 0000 steel wool I'll be rubbing it in with a white 3m rubbing pad. :)

    The little bit of stain you mentioned: does it bring out the grain a bit? If I give the top one wipe with a diluted 1:4 Birchwood Casey Walnut stain:water solution and then resand at 400 and 600, will it pop the grain/flame any better? Would it be easy to screw up a perfectly good maple top by attempting to stain it and then sand back evenly? Remember this is my first try at finishing.

    Thanks for all your help! It's making things go a lot smoother.
  12. Yeah, you got it! I actually used a color called "antique maple" on my maple just to make the character come out. The wood had a little pinkishness but I had one of those damned Sadowskys in my mind's eye and that's what I was shooting for. Sure, try using some stain in the oil too and, of course, try it the conventional way too. But do it on scrap! darker stains seem to take a bit to penetrate so it will take some patience. And no matter what the stained wood looks like before the oil, it will look better after. That's another fine aspect of this "idiot proof" finish. Also, I think it was Tim Barber that suggested using a single directional light source for sanding. It's a good idea for staining and oiling too. A point light source REALLY makes figured wood sparkle.
  13. philthygeezer


    May 22, 2002
    I finished dry - sanding the body to 600 grit early last week and set the thing to dry for a week, warming it with a hair dryer on two occasions. Today I started finishing the back first so I could learn a bit before getting to the front.

    This morning I diluted the Tru-Oil 50/50 with mineral spirits (BC recommends mineral spirits for dilution) in order to make the Tru Oil penetrate as deep as possible. Then I applied it to the top back 1/4 first. The top back 1/4 became the back 1/3rd and I worked my way around the back and sides over the course of the day.

    When the finish started to get tacky, I applied more diluted Tru Oil and scrubbed it into the wood with a white 3M rubbing pad until there was no oil left on the surface of the wood. Once the back was completed on the first coat, I let it sit for awhile. A few minor flaws showed themselves as it dried. So I made a diluted 1:3 Tru Oil:Mineral Spirits, applied a liberal amount and scrubbed across the flaws with the 3M pad until they were mostly gone. So far as I can tell, the finish is all IN the wood instead of ON it, so far. This amounts to about the third coat. At least three more will follow.

    The Tru Oil is great! The Alder back is sparkling! Where the grain crosses the contour of the body, it looks like Tiger's eye. This stuff is wonderful.

    Thanks for all this good advice Hambone. Is there anything I should worry about when I do the top next? I plan to to the whole body in about 7 coats or so, alternating back to front.

    Should I let the thing dry between coats, or should I just keep forcing the congealed oil in with the rubbing pad?
  14. Well, there are actually 2 steps here and you are well into the first and that's sealing the wood and pore filling. I would let it dry between coats - as long as it takes to get hard and not block up your abrasive when you sand. I would smooth things out every couple of coats. You can wet sand here and that works well, - just beware that oil is delicate and it won't take much. The sanding between This levels the surface and allows the oil to fill in the lower areas. The smoothest, most reflective finishes don't have surface flaws and that's what you're fixing here. After a few cycles, everything should be level and you can begin to build the glossy top coats. Don't limit yourself to a preset number. Get to that number and re-assess the progress. Remember, my pics show 12-15 deliberate coats (doesn't count small touchups and such) and it's not where it could be as far as a glassy finish.

    It sounds like things are going well though and you're having some fun. See what I meant by easy? Because the process is so slow and deliberate, rushing mistakes are eliminated. And since the process is easily reversible and restorable, you can fix any flaw that haunts you.
  15. Groove Theory

    Groove Theory Grizzly Adams DID have a beard.

    Oct 3, 2004
    The Psychiatric Ward
    Hambone, So what do you use to polish the Tru-oil finish to a gloss shine after all your coats are on there? is any one specific product better than another?
  16. The Tru-Oil has a nice gloss on it's own but can be improved by polishing. As I mentioned in my earlier posts, I use Turtle Wax Buffing/Polishing compound as my next to last step. A little on a damp rage and buff away. You'll see the results immediately but it won't stop there. The final step is a waxing. I use Minwax paste wax. It build up a couple of coats, letting it dry then buff to a high gloss.
  17. Hambone,

    The pictures are gone. Can you post them again? I'm going to do some necks with true oil and I'd like to see te results over maple. I'm using birdseye for the neck and fretboard.
  18. Juneau


    Jul 15, 2004
    Dallas, TX.
    Just a small suggestion to count_funkula, you might consider something that may sound strange at first. But Kiwi Natural Shoe Polish actually works quite well as a neck finish and to me, isnt as sticky as a tru-oil finish can sometimes get after a short time of playing on it. Its also real cheap and easy to find at your local grocerry store. Sheldon Dingwall actually recomended it to me when my neck started to get a little dirty. Its been awesome as an alternative to the oil. You can also buff it to a nice satiny shine as well.
  19. munkyboy


    Feb 1, 2004
    Are they using Kiwi as a finish by itself, or as a final step over oil?
  20. Sheldon D.

    Sheldon D.

    Oct 3, 2001
    We use the Kiwi wax over an oil/polyurethane finish. Although some woodworkers will use wax only as a finish for furniture, guitars need the protection of the oil as well.