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27 October 2013

One in the eye for the Grand Poobah

I've been doing some more work on my Grand Poobah acoustic ukulele build this week. There have been highs... there have been lows. Here's the update!

[Sorry - broke the link to this photo as part of the Google Photos update. Move along...]

That feeling when you can see disaster approaching, but you can't do anything about it.


The eye of the Poobah!

I'd been wondering about the acoustics of the Grand Poobah and it started all sorts of research into what makes an acoustic instrument sound good. The following snippet from the Petros website summed up the general feeling out there on the internet...

"The harder the back wood is, the less energy it absorbs and so the less it vibrates. The less it vibrates the more it projects.  The cost of great projection is reduced tonal color as contributed by that wood.  Conversely, softer woods vibrate more and produce great tonal color, but project less well. ... The top is the heart of the instrument.  It 'makes or breaks' the sound of a guitar, regardless of what back wood is employed." ~ Petros

I'm certainly dealing with hard wood in this project. Based upon what I was learning, I figured that I would thin the front out using my router. Of course I ran the risk that it would all fall apart on me like the back did, but I was prepared to give it a go. The picture above shows the finished "eye" post-routing. It looks ugly, but this will never be seen... unless it falls apart.

If you're interested in learning a little more about wood and acoustics, then you could do far worse than check out the following video. Aaron Keim's words of wisdom start at about the 3 minute mark. Thanks to +Gunnar Green for bringing this to my attention.
 


Having routed the sound-hole I then spent a lot of time working the front and body so that they fitted nicely. I managed to level everything so that everything fitted where it needed to be. Here are all the parts to the jigsaw after I'd wiped them down with white spirit getting ready for gluing. 


Wow! Isn't this great! I've glued and clamped everything together. This reminds me a lot of some sort of RoboGeisha-type monstronsity. I love it!

Can you spot the big lesson here? Yes... I don't have enough clamps. I knew this at the time, but unfortunately, everything was glued so I couldn't do anything about it. I just had to leave it and nervously wait for glue to dry.

Check out the picture below. I reckon that this young lady would be an ideal choice for modeling the Grand Poobah when it is finished.

(Photo courtesy of my hero Hanakuma Yusaku)



Oh dear, oh dear! Look at all this crackage! The front has split and there are unsightly cracks all over the place. What on earth would I be able to do about this? Having spent hours and hours getting everything to fit just right, once glued, it didn't quite fit, Damn!

I'll admit that I did consider filling. I've been saving some sawdust for just this eventuality. I figured that I could make a sawdust paste with wood glue and that would be a clever way to deal with it.

On reflection I decided that actually this would be a big mistake. For a start, there would probably all sorts of issues with the glue not taking wood stain, but more fundamentally than this I would be compromising my vision. When I set out to make this instrument, I wanted that "half-a-surfboard-washed-up-on-the-beach" look.  Recycling and things-not-being-perfect are big themes in this build. I don't want a perfect instrument. I want an instrument that has lived... a one-off... with quirks... with history. The cracks have to stay!


After that rousing speech, I'll give you a closer look at the crack on the front. Ouch!

I had to resand the instrument to round it all off again. This time, I worked through the grades of sandpaper to get that baby's-bum smoothness. Do baby's have unusually smooth bums then? Don't answer that question. :-S


Here I am, readying myself for staining the wood. I made this little jig to hold the instrument while it dries. 


I said that I would test out the wood dye that I'm going to use prior to staining the instrument. I almost forgot! ;-)

Yep - this is looking good. I've decided to go for a dark stain to bring out the beauty of the tight grain. My original mock-up hinted at a light wood, but I'm letting the wood guide me here. I think it will go well with the ebony fretboard I'm going to make for it.



This is the wood having been stained. I'm really liking this. I went out of my way to try and get the stain into the cracks with a small paintbrush. 


I started off with a satin lacquer on the left and applied 3 coats of this before deciding that I wanted a gloss finish. I sanded smooth with 200 grit and applied one coat of gloss on the right and left it at that. 


When it all felt dry I couldn't help myself and set about fitting the tuners. These are those vintage tuners I mentioned in my last post. I'm using a ruler to help me to get them straight. I used a hand-drill to help put in the screws... bloody hell this wood is hard!



Forget building ukuleles... Ever wanted to build your own Scarab? Now you can with a little help from Team Scarab at the University of Nebraska State Museum. Check out the downloadable instructions.

Earlier this week +Darren B  mentioned that the Scarab is my "totem". I hadn't thought about it in this way before. I like it...

"A totem is a being, object, or symbol representing an animal or plant that serves as an emblem of a group of people, such as a family, clan, group, lineage, or tribe, reminding them of their ancestry (or mythic past)" ~ Wikipedia


Look at this! they're in! I am loving the look! Surely I can't bugger it up now! 


One last shot before I close this post off. It will look even better with strings! :-D 

4 comments:

  1. It does look good, but I think you should have routed out more in the top. The wood really needs to be thin where the bridge sits, that's your source of vibration. Not to say it can't sound good now, I've seen so many instruments that in theory should be completely silent and still they sound good.

    My acoustic sopranos typically have a 1.5 mm hardwood top or a 1.7 softwood top.

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  2. Oh... don't say that Sven! I purposely left the bit where the bridge will be thick to give it more support. Maybe I should have sought your advice first! Oh dear. It's too late now! If nothing else, it will make a great wall-hanger ;-)

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  3. One in the eye ?
    Crying for his art: Amazing pictures of the Argentine artist who weeps paint onto canvas.

    http://www.mirror.co.uk/news/weird-news/leandro-granato-pictures-eye-painting-artist-2361039


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  4. Squirting paint out of his eyes! Oh my....

    ReplyDelete