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Thread: Yet another mess-up

  1. #1
    Join Date
    Mar 2017
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    Arlington, WA U.S.A.
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    Default Yet another mess-up

    I'm not even going to mention all the feelings I have experienced the past day or so. I'm humbling myself again to ask for help. Please tell me it gets better.

    I was excited that the uke is in the finishing stage. I had bought and applied 3 coats of Aqua Coat as a pore-filler (with little understanding of what that even means or looks like). Looked good to me. Somebody said use a foam brush to apply Tru-Oil. I watched a video where Robbie O'Brien said "wipe it on and get away from it". Then watched one, suggested here, by somebody who makes Mye Moa ukuleles. That was very helpful and it was then that I realized that the end goal drives your choices about how to apply Tru-Oil. Glossy versus not glossy. That may explain the differences.
    I did 3 coats of Aqua Coat because that's what I saw on a video, again, not realizing that Koa isn't the same as Rosewood. (I have since learned that it's one of the species with the biggest pores!) I showed the instrument to a guy locally who observed that it didn't look like it was pore-filled. He then showed me a couple of his guitars and then I could see the purpose of pore-filling. I realized that I could have put any number of coats of Aqua Coat and not stopped with 3. But, again, it looked good to me... (not having any clue what I was doing).
    I slathered on 3 coats of the Tru-Oil and thinking that I had adequate"build" so as to "level sand" which I did.
    Things were still going okay I thought. I spotted a horizontal line, somewhat of a low spot about and inch or so long and decided to take care of it at this early point. Used a scraper and then 0000 steel wool. Hit it with a coat of Tru-Oil and then 2 more, all 3 were rubbed in more like French polish, which was what I did on my other uke successfully.
    From the photos you can see the color difference compared to the surrounding area. You might also see that I've successfully removed a LOT of wood! And perhaps you can see that there are still imperfections in the wood. Different ones that weren't there earlier.
    Is the fact that I've blown through the layer that had the Aqua Coat to reason for the difference in color and the lack of any glossiness at all?
    Can I take the whole top down with a random orbital sander and start over? At the least, can I sand to blend in that low area with adjacent areas?
    When I'm done with this, I'm going to compile a list of the things I have redone. There are mistakes from my first one I didn't make this time; no need -I made plenty of new ones!

    I take up way too much time with my stuff on this forum. Apologies!
    IMG_20201028_174426__01__01.jpgIMG_20201028_192738__01.jpgIMG_20201028_192802__01.jpg
    "Why is it that you never have time to do it right the first time, but you always have time to do it right the second time??"

  2. #2
    Join Date
    Jun 2020
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    273

    Default

    That's a nice instrument! I like the purfling. I'm a sucker for abalone. If it's any consolation, I built my first instrument (an electric uke no less) in 1999 and I'm still making mistakes more than 20 years later. It's just part of the hobby. So don't be hard on yourself.

    Also realize that there are differing versions of success. Especially with finishing techniques. Some people like a totally smooth pore filled glossy finish and others like a thinner looking more natural finish where the pores show through. There's really no right or wrong, and while there are a dizzying number of variables it's really about finding what look you like and then how you can get there.

    Which brings up probably the most important tool in your finishing arsenal. Practice. Get your hands on some wood scraps - cutoffs from your build - and finish them! Do this over and over until you're comfortable with what you can accomplish. You can even "damage" one of your test pieces if you want practice repairing. When I try a new finish technique I may do half a dozen tests or more before I touch a "real" project. It seems like a lot of time to invest but it's a good way to reduce variables and end up with a known result.

    For your uke - you may be able to sand out that spot and refinish it. Tru oil blends into itself nicely. It's hard to comment on why it's darker but it may be because you sanded through the aqua coat, which was sealing the wood and preventing the tru oil from sinking right in. Tru oil has an amber tint (pretty much all oil finishes do) and if it soaks in more it'll get darker. So if I were you I would GENTLY sand just that area with fine sandpaper until you removed the discoloration and then start over with the aquacoat and top it with tru oil.

    Any time you're sanding, buffing, polishing on a finish you need to train yourself that less is more. You can always sand more but you can't sand less! Train yourself to use finer sandpaper than you think and to stop prior to when you think you are done. Pause, look over your work, hold it up to the light and check for scratches or imperfections. Make sure you're aware and informed of what you're doing and slow down if you're not.
    Last edited by dwizum; 10-29-2020 at 07:32 AM.

  3. #3
    Join Date
    Oct 2014
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    Little River, California
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    Default

    What it looks like to me is that you have created a concavity there over the tail block. Sanding and then trying to match up that part of the finish with the other parts is gonna be tough. The nice thing about finishing (if there is a nice part) is that you can take it all off and start over. The overall finish does not look good to me anyway and if it was me I would take it off on the entire top with an orbital sander going back to near bare wood and start the process over again. Hey, it happens.

    As for pore filling it does take experience. When you are sanding back look for little shiny spots. These are the pockets which have not been filled yet. Pore fill, sand until you get an overall dull look. This means you have reached a "level sand" and your pores are filled. As you get experience you will be able to spot those little shiny things.

    Good luck!

    Old saying: "Finishing is the Achilles heal of lutherie"

  4. #4
    Join Date
    May 2011
    Location
    So. Oregon
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    I'm going to throw this out here even though it may not be directly pertinent to your problem. Someone might do search for AquaCoat and koa, find this, and be saved from disaster.

    NEVER use AquaCoat over raw koa. Sometimes, but not always, AquaCoat causes koa (and its near cousin, Tasmanian blackwood) to discolor with a greenish cast. That can be a big problem. Apparently, this is a potential issue with any water-based product and has been reported on various lutherie forums. To pore fill koa, use epoxy or CA or something else that doesn't have water in it. Also, don't use a water-based sealer or finish over raw koa. At a minimum, seal first with two or three wash coats of wax-free shellac.
    Last edited by saltytri; 10-29-2020 at 09:49 AM.

  5. #5
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    Mar 2017
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    I appreciate the graciousness of you folks toward me! Very much!

    I did try to level that up best I could and I think it's not bad. I'm a little concerned because I'm not sure if I'm into that Walnut end block or not but I stopped quickly as I realized something was not quite right. At this point I'm happy just a button it up and move on in life. You learn from your mistakes and some of them stand as reminders every time you look at something, no?

    Now to do the pore-fill again. But because of the concern about Aqua Coat and Koa, although I saw none of that my first go-around with this uke, I'm prepared to do yet something else. I know that a number of you do the CA glue trick for pore-fill. I watched Beau Hanam's short video on pore-filling Koa and best I can see he used medium CA glue and simply rubbed it on in swirls and then straight strokes to end. He did a small section at a time. I don't know how you avoid the rag sticking to the wood but I'm sure I will pull up if that starts happening. Any tips?

    And, yes, I will be practicing on something!
    "Why is it that you never have time to do it right the first time, but you always have time to do it right the second time??"

  6. #6
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    Mar 2017
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    Here is what that top is looking like.IMG_20201029_170741__01.jpg
    "Why is it that you never have time to do it right the first time, but you always have time to do it right the second time??"

  7. #7
    Join Date
    May 2010
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    Cairns, Australia
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    If you are going with CA then I can't stress enough you need good ventilation. A fan blowing the fumes away from you and your eyes is the very least you should do.

  8. #8
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    Thanks, Allen! Good idea!
    "Why is it that you never have time to do it right the first time, but you always have time to do it right the second time??"

  9. #9
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    How many coats of CA glue does one use for Koa? Do you sand between coats? Waiting time between coats?

    Thanks
    "Why is it that you never have time to do it right the first time, but you always have time to do it right the second time??"

  10. #10

    Default

    I have found aqua coat to be a terrible pore filler. The only way I have used it successfully is to pore fill about half way through a lacquer finish when you have enough coats on so you don't sand back through and the lacquer has reduced the size of the pores. I find CA and epoxy both superior. I'm also wondering if you sanded back to bare wood after you pore filled or left a thin coat of aqua coat on the entire surface. That's something I would not do. I would rather have a coat of shellac on bare wood or epoxy.

    To answer your question. If you don't have top too thin issues of course you can sand back with random orbit or by hand.
    Michael Smith
    Goat Rock Ukulele
    www.goatrockukulele.com

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