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Thread: Build log for #003 - A Pineapple

  1. #1
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    Default Build log for #003 - A Pineapple

    #002 has to sit for a while to let the Tru-Oil harden so it's on to #003. This is going to be my take on a travel uke. We're off to the tropics in seven weeks and it would be nice to take an instrument along.

    One thought from the outset is to using a barrier coat on the inside to retard moisture changes since it will be going from very dry to very humid overnight. Another thought is to choose woods that will forestall any grief from officialdom. Much has been written here and on guitar forums about the possibility of losing an instrument to an overzealous customs person when crossing borders. This may or may not be much of a threat depending on who is doing the opining but why take a chance? So, there will be no tropical hardwoods in #003. A respected builder told me that he prefers to use well-tested woods because, among other reasons, his instruments are made to be playable for many decades. I certainly respect that opinion and practice but it seems far-fetched that anyone will want to play my little uke even ten years from now.

    For the neck, I chose a piece of 2x8 red alder that has been in the woodpile for 24 years since I bought a bunch to make some furniture. I weighed it along with Honduras mahogany and Spanish cedar neck billets and the weight per cubic foot was about the same for all three. So, OK there. I recall reading once that red alder doesn't have a great reputation for stability. Again, that might depend on who is saying so but I have to believe that this board has been around long enough that it won't get all twisted up. Just to make sure, the neck blank was laminated and slotted for two carbon rods. Two rods might seem like overkill but they are a bit smaller than some at .22" diameter and it's no more work to cut two slots than one once the tools are set up. These are arrow shafts, which are readily available and inexpensive.





    The body will be made out of some nice fiddleback myrtle from Island Tonewoods on eBay. Those folks put up some nice wood at reasonable prices and are a pleasure to deal with. This is a soprano set but I've sized the body as big as possible without running out of wood, so it's about halfway between a soprano and a concert. The scale length will be 14.75" (concert) with 14 frets to the body so that the bridge isn't too far south.

    If the goal is to stick to North American wood, the fretboard presents a problem. Most domestic hardwoods are light in color. The most widely available exception is walnut but most walnut isn't as hard as the usual fretboard species. Some online research led to mesquite, which is quite hard and is occasionally mentioned as a fretboard material. The local hardwood supplier had a few boards, out of which was a single piece of slant-to-quartersawn. It has pretty large pores so the plan is to fill with epoxy before cutting the fret slots. Before cut, the surface of the board was a nice warm brown with a tinge of red and not much color variation in the grain. Much to my surprise, the inside was lighter, with a distinct grain pattern that includes a lot of gray. The bridge blank shown in the photo has the oxidized surface up so the difference in color can be seen. It will be interesting to see what the fretboard does over time.



    Continued....
    Last edited by saltytri; 01-23-2012 at 03:24 AM.

  2. #2
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    ....here.

    The pineapple shape was chosen just because I like it. Some alder strips were lying around so one was sanded very thin to make a bendable batten. This was used to lay out the shape along with some other precision drafting tools. Don't need no stinkin' CAD!



    The two halves of the mold were temporarily screwed back-to-back and the shape was cut out on the band saw.



    LMI has some neat little clamps that make it easy to split the mold. The halves are keyed at both ends by clamping the sides together firmly, drilling a 1/2" hole centered at the joint line and then gluing a piece of 1/2" aluminum rod to one side.

    Last edited by saltytri; 01-31-2012 at 07:06 PM.

  3. #3
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    Hey man...you are on fire.
    Very nice myrtle.
    So you draw this pineapple shape yourself hun...I really like the shape you draw..

    Is the neck side of the body completely flat (non-radius)?
    Last edited by UkeforJC; 01-22-2012 at 12:49 PM.

  4. #4
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    Yes, I drew it to taste. A pineapple should be tasty, right?

    The top of the body is flat just where the neck mounts. That makes it a lot easier to to get a good fit.

    Now, back out to the shop to fan the flames.

  5. #5
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    In keeping with the domestic wood theme, poplar will be used for the solid linings. Some sticks were split from a board using a small hand maul that we keep around for kindling. The sticks were parallelogram in section because the board wasn't quite quartersawn. They are then cut on the band saw following the split face so the sticks end up with vertical grain.



    After sanding to dimension, four strips were bent on the hot pipe and fitted to the mold to set in place. Poplar bends very easily so this wasn't much of a job. Still, it makes some sense to bend the linings before the sides to get some familiarity with the shape. I think this will make the side bending go easier.



    Next, some left over alder was sanded down to about .070" to use for the two blocks. I've used Baltic birch ply before but that would violate the rules because there is no way of knowing the country of origin. So, the plan is to cut the alder into squares and laminate the blocks in place using alternating grain directions. This has the advantage of yielding a perfect match to the curves of the sides.


  6. #6
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    The laminated alder blocks idea went the way of most bad ideas. Some birch ply stamped "Made in USA" turned up and that satisfied me.

    Each side was bent and left in the mold overnight. This eliminated spring back. Don't use clamps like these without some pads, though. They left a few little gouges in the myrtle. Even though that was a slight error, this part of the project turned out well. The end result was that the linings fit the sides very closely and this made it easy to glue them together.



    The clamps on the mold are very useful to get good, tight joints at the ends of the sides. Just make sure that the sides are a tight fit in the mold and use a little pressure from the clamps to bring the joints into good contact.



    Three quarters of a box! The bridge plate is .030" carbon fiber sheet. The braces and tone bars are from a really nice piece of Western red cedar. As best I could count, there are over 100 lines to the inch, perfectly quartersawn. The board isn't wide enough for tops, unfortunately, but it certainly cuts nicely with chisel and finger plane.



    Like the last one, the top was done in a 25' dish but is flat where the fretboard will sit.
    Last edited by saltytri; 01-27-2012 at 07:07 PM.

  7. #7
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    The rosette was made out of black ABS plumbing pipe, alder and white wood purfling strips. The ID of a pipe coupler was bored to leave a thin, black wall. The wood strips were glued around it and a black ring was machined to fit over the wood.





    After the whole assembly was glued together with CA, a thin section was cut off and glued into a channel on the top.


  8. #8
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    This is finally looking like what it is supposed to look like. The body is ready for final sanding and the neck is roughed out with the fretboard glued in place. I've got to round up some small plastic rod to make side dots and then the neck can be finished.



    The pore fill on the fretboard came out as hoped. After the epoxy fill coat was fully hard, it was sanded very carefully just until the sandpaper was picking up a bit of wood dust mixed in with the epoxy dust. A few small pores can be seen but no more than on a rosewood surface.



    The alder neck has been a pleasure to shape. It can be carved and sanded easily and without much drama, except whatever gets caused by operator error.



    Tapping the body is very pleasant. It has a complex tone that seems to have two primary notes plus some other sounds pitching in. I'm not sure what that will mean in the end but it's probably better than if the thing just went "thud."
    Last edited by saltytri; 01-31-2012 at 07:13 PM.

  9. #9
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    wow...you build fast..
    are you a professional luthier?

  10. #10
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    I'm not even an amateur luthier. I'm a home hobbyist beginning instrument maker trying to sort out what works and what doesn't. In a few years, I might have a glimmer of an idea.
    Last edited by saltytri; 01-31-2012 at 07:18 PM.

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