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Finishing Cocobolo

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  • Finishing Cocobolo

    I just finished making a small box out of a cocobolo wood turning blank. I actually started with a 3"x6"x6" turning block, cut a top off, bored out the inside, and then dadoed the bottom to give it legs. The result is that the grain matches all the way around including the top.

    I have never used decorative grain wood before and could use some suggestions for finishing it (this was a test/first try on decorative wood). I borrowed a book on finishing from a friend which was informative but basic. I want a rich looking finish. From the book I and was thinking about tung oil.

    One concern is that when I wiped it off with mineral spirits after final sanding, the two end-grain sides temporarily turned black from soaking up the little bit of moisture. I would think that tung oil would do the same thing but more permenantly. Help is greatly appreciated! My only finishing experience is stain, poly, and polyacrylic.

    Thanks in advance for any pointers.

  • #2
    I recommend skipping anything oil-based on Cocobolo. The oil that is in the wood contains a chemical that prevents oil finishes from curing. Two, three months dry times aren't any fun at all.

    I recommend either shellac, or lacquer. Shellac can be applied by spray, brush or wiping. Lacquer, in my opinion, is best sprayed (there are a couple brush on formulated lacquers, but I find them problematic). Spray cans of lacquer and shellac are available, and shellac is available in pre-mixed cans as well.

    If you're interested in any of these paths, I can lend help in application. These are fast dry finishes that act a little different than what you're used to.



    • #3
      I have no clue how to help, but sure would like to see a picture when your done, it sounds awesome.
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      • #4

        Thanks so much for your input. The book I borrowed doesn't say much about shellac or lacquer so I probably need to go get another book [img]smile.gif[/img] . I have a few quick questions if you don't mind.

        1. Can I get the needed supplies at Home Depot/Lowes. Woodcraft is about an hour from my house (joys of living in a big city) but I will go there if I need specialty products.

        2. Am I likely to have end-grain darkening with either option (since the matched end-grain on the sides and top is the prettiest feature).

        3. You mentioned that you could help with application. In the past I have used a spray can of lacquer from HD (on cheap wood) and got a very rough finish even though it was well sanded. After many applications with sanding between, I finally poly'd it with a brush. I now have the porter-cable HVLP spray gun as an option but that seems like a lot of cleapup for such a small project. Any pointers with laquer or shellac?

        Thanks so much for the help!



        • #5
          1. Probably. I don't go to the Big Boxes too often, so I'm not entirely up on what they carry. They surely should have Zinsser Bulls-Eye clear shellac, which should do you fine in the shellac arena. Shellac suffers from a limited shelf life, the cans have a date stamped on the bottom, buy the newest one. Don't know on lacquers. If your HD or Lowe's doesn't have what you need, a paint only store like a Sherwin Williams should have it, or they can be mail-ordered from people like Jeff Jewitt. Shipping can be a bit much, though.

          2. I'm almost sure you'll be OK on end-grain darkening, but I'll make a test at home before committing.

          3. What you experienced isn't uncommon with spray cans, since they aren't adjustable they require good skill. Chances are good you were too far back and you were dry spraying. Takes some practice. If you're comfortable with a brush, I think that would be easier for a small piece.

          I'm a little light on lacquer experience, because I'm allergic. If you want to spray lacquer it, I'd recommend getting a couple extra cans and practicing on scrap, even cardboard. Unless dirt gets into the finish, neither lacquer nor shellac needs sanding between coats, each coat redissolves the previous. Sanding just increases the number of coats required to apply.

          Let me know which direction it looks like you'll be going and if you have other questions. I'll test a bit of shellac either tonight or tomorrow for end-grain darkening.



          • #6
            Thanks Dave! I stopped by Lowe's today and good call! they do have Zinsser Bulls-Eye clear shellac. I'll try it with a brush and see how it goes.

            As far as the end-grain darkening, I can try a little on the inside of the box lid. I rabbited the bottom of the box lid around so it fits the inside of the box. This gives plenty of end-grain for testing. Anyway, this was a test project for learning purposes (and maybe the possibility of an end product [img]smile.gif[/img] ). If it doesn’t turn out perfectly that’s ok.

            If you happen to look at this post again, when I got home today I noticed that the box top is cupping so it isn’t fitting perfectly anymore. I clamped it down and plan to leave it like that for a while. I had this problem when I cut the top off the turning block for the box top. I don’t have a band saw so I took 2 passes on my tablesaw. On the second pass, I had to drive shims in the previous cut so it wouldn’t bind. Since I don’t have a jointer or planer, it took a lot of sanding to get the top uncupped. Looking back, I’m not surprised in the cupping. Any words of wisdom?


            • #7
              Any words of wisdom?

              Wisdom? Maybe. Encouragement, well....

              Welcome to the world of Dalbergia retusa, also known as Cocobolo. My wife is Costa Rican, where Cocobolo is from, it is kind of their unofficial national wood. We have a lot of Cocobolo knick-nacks, and a lot of them are warped. Stuff isn't the most stable wood in the world.

              What I would have done different. I would have cut the top free, and let it "relax" for a couple days to see what it wanted to do. Sometimes you'll cut off a piece like that, and it will cup, but in a few days it will move back more toward straight. Sounds like that is what may have happened to you.

              This is a general concept that I apply with all woods. Right now I have the parts for a cabinet face frame and door in Pine "adjusting" out in the shop, cut Sunday. Starting tomorrow or the day after, I'll start final milling. Fewer surprises this way.

              Let me know if there's any way I can help out. If you have picture capability, I bet I'm not the only one here who would like to see it. [img]smile.gif[/img]



              • #8
                Dave, once again thanks for your help. I don't have picture capability but since RixWorx is interested as well, I'll see if I can borrow it from a friend when the project is finished. Thanks again for all of your help! -Robert