Crystal Heart ukulele

[dekutree64 713]

This is looking really good, watching your progress has been an intriguing journey, and I look forward to seeing the rest. I have a question for you: why was shellac your finish of choice? You mentioned that you weren't a fan of the mirror-like gloss (which looks well done; good work). There are many wood finishes out there, and something else could have given you a more textured look. I know nothing about guitar (or ukulele) construction, so what is the benefit of a shellac finish?

A fine question! And the answer is that I have yet to see a guitar finish that truly speaks to me.

 

I started with shellac because I'd always hear people sing the praise of how beautiful French polish is, and that it's one of the most acoustically transparent finishes as well (because it's so thin, it adds very little mass to the soundboard). Combined with the materials being cheap and safe, and dust being far less an issue than with something slow drying like violin style oil varnish, it seemed like the perfect fit for me.

 

But on my third guitar, I decided to scrape the soundboard rather than sanding it, and the texture was so nice I couldn't bring myself to do anything more than the thin coat of shellac I put on it to keep it clean while working. That's when I realized there might be a better goal than flat and shiny.

 

I've tried one other style, which was to wipe on shellac and then buff it out with a small, firm pad and just a drop of alcohol to get a little friction with the shellac. That's probably my favorite so far, but I still feel like there's something better that I haven't tried yet. Other materials are definitely something to look into. I could also use a different finish on the back/sides than I do on the soundboard. I'll probably stick with shellac for the neck, at least, since I love the feel of it.

 

But back in the present, I carefully scraped down the nibs with a razor blade (I think my "dust pearl" theory may be correct), then scraped everything except the inlays, and then did a few more rounds of polishing. Much better, but one nib grew back, and one area had lint embedded in the shellac. So a few hours later I scraped those down, and polished some more, and I'm pretty happy with it now. Ended up with two minor divots where the evil nib was (you can see them right at the edge of the lamp reflection, by the heart), but I think I'll leave it alone.

 

Which means, I can finally glue on the fingerboard, and then the bridge, and then the back, and then trim the back overhang, level the fingerboard, install frets, and string it up I may French polish the back/sides to match the top, but that can be done any old time. Don't even have to take the strings off

[dekutree64 713]

Lots more progress!

 

Scraped the neck's fingerboard glue surface clean, because it had gotten all grubby due to handling throughout the build. Also scraped the finish off the soundboard where the fingerboard extension lays, because glue doesn't stick to shellac. I forgot to take a picture.

 

Then lightly scrape the fingerboard to freshen the surface (oily rosewoods like this don't glue well after they've sat for a while), heat everything up, and stick it down with some extra watery hide glue, because my  usual thick mix doesn't squeeze out completely. It seems I didn't put quite enough water in this batch, plus was a little slow getting it clamped, so the glue line isn't invisible. Oh well, not worth the effort of peeling it back off and regluing just for a minor cosmetic flaw.

 

Then locate the bridge, by laying the straightedge/ruler along the high and low string paths to get it centered horizontally and at the correct distance. I put it about 1/64" farther back than the exact scale length location, because the strings need some amount of extra length added for intonation, but I couldn't find anywhere exactly what is standard for ukes. But I can make an educated guess, so this should be a safe start, and the saddle on this one is wide enough that I should be able to get as far back as needed with room to spare. Then stick lots of masking tape bits around it to mark where it goes, incase I bump it out of place on the next step.

 

Then score around the bridge with a fresh and pointy x-acto knife. The goal is to go precisely through the finish, without cutting into the wood.

 

Then scrape away the finish down to the wood. This is one reason most people use boring square bridge shapes, so it's easy to scrape. I tried using a chisel, but it was too tedious, so I decided to treat it as an inlay and use the dremel router. At this rate I'm going to lose my hand tool purist gloating license Lots of tape to protect the finish from scratches:

 

Unfortunately the tape itself damaged the finish Plus there's a fingerprint that doesn't seem to wipe off.

 

I guess I should have given it a day or two to harden... or stuck the tape on my arm a couple times to reduce the stickiness. So, I had to do some careful polishing around the bridge area to flatten it back out, which went well.

 

Then glue the bridge. Made a little caul to fit it (piece of wood, with two more carefully thicknessed pieces glued to it to fit the wings, and then coated in cork to distribute pressure evenly over the whole bridge surface). I hate making cauls, because it encourages repetition of the same shapes so you can reuse it. I like doing new things every time, but it's easier to make a caul than to French polish around a bridge... at least at my current polishing skill level. Note: It's rather tricky to get two of those big clamps through such a small soundhole...

 

Oh, and inside the box I just used an old cork lined caul I had lying around from a steel string bridge plate, which I made from a scrap I'd been using as a backer when drilling holes in things  The paper is to make up the thickness of the bridge patch on this one, since the bridge wings stick up slightly above it.

 

Next day, clean up the last bit of glue squeeze-out that I couldn't get with a toothpick while it was still wet. I thought I might not have gotten glue spread quite all the way to one corner of the bridge, and it turns out I was right, which meant the water I was cleaning with could wick under that corner, and soaked into the wood and up through the grain under the finish... leaving an ugly little stain, and a rough patch of finish due to the swelling underneath of it. So I had to let that thoroughly dry, then wick some watery hide glue under that corner to make sure it's fully glued, let that dry, then flatten the finish as best I can with the bridge in the way. Nothing I can do about the stain though Next time I'll stick with damp paper towels instead of drops of water for the glue cleanup.

 

But it's all looking pretty good. The shiny French polish is growing on me. Especially now that it's had some time to dry, the grain texture is showing a bit more. Still doesn't feel as nice to the fingers as the wipe-on finish, but it's rather hypnotic to look at

 

I also did the label painting that will be visible through the soundhole. Most people glue in a paper label, but I think it's cooler to do it in acrylic paint I paint a little picture sometimes too, but I couldn't think of anything that seemed classy enough while still being relevant.

 

So all that remains is gluing the back, trimming the overhang on that, finalizing the neck, installing the frets, and making the nut/saddle.

 

I may also shave the back braces a touch more. From what I can tell of the tap tone with the back spool clamped on, its resonant frequency is a little higher than it should be relative to the top. But I'm not sure exactly how it will change after gluing it on and removing the heavy clamps, so I haven't decided for sure whether to do anything to it.

[dekutree64 713]

Strings are on! Not totally done yet, but very close. Which means that if anyone wants to see/hear/play it in person, I'll be at Midwest Brony Fest this weekend and will bring it.

 

But on to the work of the last few days. First, glue on the back: The humidity has gotten a little high, so I tossed it in the oven and warmed it up just a bit for an hour to dry it down to 35% RH. Also tossed in the whole instrument for the last couple minutes to warm it up so the glue wouldn't gel so fast. Then spread glue all around the rim, stick the back on, and start screwing down clamps as fast as I can.

 

Then I did quite a bit more carving on the neck, blending the fingerboard into the shape, and finalizing the thickness (made it a little thinner at the nut end). Turns out the fingerboard glue line really is quite thin after all. Not 100% invisible, but more than good enough, and would have been a total waste of time to peel it off and reglue it.

 

Then sand the fingerboard flat, polish it up, file the edges of the fret slots just a bit so they have a tiny bevel rather than being a sharp edge (makes it easier to get the frets in, and less chipping if they ever need to be pulled out). Use some flush ground nippers to clip off a piece of fretwire about the right length for each slot, and then clip off some of the tang at the ends to fit over the binding.

 

Unfortunately, the nippers don't cut it flush enough, so I have to file the last bit of tang off. I wish I had a better way to hold onto the fret for this, because it's hard on the left hand finger muscles after a while.

 

Then I realized I forgot an important step, which is to grind down the barbs on the tang so they'll fit into the slots without too much force... which unfortunately the fancy tool I have for barb filing only really works when the wire is still in relatively long pieces. So I had to do it the less fancy way, holding the fret by the tang with the nippers and hitting each little barb with a dremel cutoff wheel to shorten it down some. Takes forever, and less accurate, but gets the job done.

 

The standard approach to fretting is to install them at this point, and then file the ends flush to the fingerboard edge and bevel them to 30 degrees. But there's another style that I like, which is spherical fret ends. They look cool, and with the method I've been using lately, I can make them slightly shorter than the fingerboard width so it's much harder to snag a fingernail under the end of a fret when plucking over the fingerboard. Plus no risk of scuffing the fingerboard with a file when shaping the ends.

 

First step is to grind a half circle as viewed from above:

 

Second step is to grind a quarter circle as viewed from the side:

 

Then a couple more swipes on the coarse diamond stone to get the "corners", and lots of rubbing on the fine diamond stone at all angles to complete the 3 dimensional shape and smooth out the coarse scratches. Then rub on some foam backed micro mesh abrasive pads to polish. Seems to get a nice shine with just two of them; the middle grit and finest grit.

 

Then when doing step 1 on the other end, I keep grinding and checking against the fingerboard until the length of the fret is just a little less then the fingerboard width at the slot.

 

Once they're all done, it's time to install. Here's the setup:

 

Fill the slot with hide glue (doesn't actually bond to the metal, but fills some of the air space in the slot, below the fret and around the tang between the barbs, and helps to mechanically lock it in), wipe off the excess with the damp paper towel, position the fret in the slot by feel and by eye, press it in a bit and get it vertical, then tap it in the rest of the way with the hammer, and then mash at it by hand with the little wood block to make sure it's in there good and flat.

 

At least, that's how it should go. And if so, the frets should be perfectly level at the end. I knew this wire's tang was an even tighter fit than most, but even with the barbs ground most of the way off, it still really didn't want to go. Harder hammering than I like to do, and a couple of them didn't seat quite 100%, so I may have to do some leveling. The vibration also popped out Shining Armor's horn So I had to glue that back in at the end... no big deal.

 

For the frets over the body, I decided to do some more dremel grinding on the barbs, pretty much entirely eliminating them and actually leaving little dips in their place for the glue to hopefully fill and lock in. Even then they took a bit of force to squeeze in. The tang itself must be a perfect match to my saw's width. Therefore, the dremel method is actually better than the fancy file tool for this particular wire, because it leaves a chewed up surface for the glue to grip, whereas the file would leave a nearly smooth surface by the time I got it narrow enough.

 

I also messed up in the positioning of two frets, getting the ends just close enough to the board edge that a fingernail could snag them... so I had to do some careful file work to shorten the ends on those, and round them back over so they didn't have a little flat spot at the tip. All in all, not the most successful fret job, but at least nothing's broken.

 

Then make the nut and saddle. I'm using bone for the saddle, and wood for the nut. Specifically, an offcut of the bridge, because it's hard enough and happened to be almost exactly the right size. Plus the color makes a nice transition between the fingerboard and headstock inlay. Here's a handy trick to get the depth of the slots right. Plane away half of a pencil, so sliding it back and forth on the frets marks a line exactly at that height. The slot depth should be as if there were one more fret there, with the string held down to it. Some builders include a "zero fret" to do that literally.

 

Mark slot positions by eye, and file them with a needle file.

 

For the saddle, I buy bone blanks from guitar supply places, which come in various sizes. Saw to length, and grind on the diamond stone to fit it to the slot. You can actually plane and scrape bone, too.

 

Then screw the tuners into the headstock (they have threads on the tapered part, just below the string post), and string 'er up!

 

I'll trim the excess later, after I'm done taking them off and putting them on repeatedly. The sound is quite nice! Not bad at all for my first uke. Certainly better than anything you can find at Guitar Center I have it strung with a low G rather than the traditional reentrant tuning, which confuses me. The low end sounds a little "boxy" to my ear, but I'm not sure how much that can be improved on at the concert size. Tenor size is made for low G tuning, so I need to build one of those sometime... although usually the reason to build an uke in the first place is to put small pieces of nice wood to good use, and most such pieces I have are only big enough for concert.

 

I still haven't trimmed the back overhang yet, just incase I need to open it back up for any reason... which is not out of the cards yet, because the soundboard deflection due to the bridge torque is a little on the high side, with around 1/64" dip between the bridge and lower cross brace. On the bright side, it's definitely not too stiff. But I wish I could take a peek at it 10 years from now and see how much farther it deforms. I think it will be ok, but I'll watch it over the next few days and see if it seems like it needs any more bracing added.

 

I'll record some sound clips later today.

EDIT: Here they are. I don't really know how to play it yet, so forgive the lack of musicality in these Just making up random stuff.

http://deku.rydia.net/guitar/crystalheart/ImprovAm_2014May19.mp3

http://deku.rydia.net/guitar/crystalheart/ImprovG_2014May19.mp3

http://deku.rydia.net/guitar/crystalheart/ImprovG-2_2014May19.mp3

 

And one more tiny one, which is Fluttershy's theme, as heard at the very beginning of Swarm of the Century, during the bunny census in Applebuck Season, and after the theme song in A Bird in the Hoof. One of my favorite little music bits from MLP

http://deku.rydia.net/guitar/crystalheart/Fluttershy.mp3

Edited May 20, 2014 by dekutree64

[dekutree64 713]

Sorry for falling off the horse on keeping this thing updated

 

After measuring the bridge rotation under string tension, it was about 3.5 degrees, whereas the recommended maximum according to at least one long-time builder is 2 degrees... so I decided I'd better add some fan braces to make sure it survives for many years to come. The alternatives are to make the soundboard thicker (impossible at this point), or to lower the bridge height (lot of work at this point). Next time I'll try the lower bridge height, but for now, braces are the way to go.

 

First gotta peel the back off... which was quite difficult and time consuming getting the glue saturated with water and working around with a hot spatula to peel it open. But I finally got it:

 

Rather messy looking, plus a lot of the linings came unglued, brace ends popped up, and I cracked the back:

 

Fortunately, splits usually glue back on invisibly. So after getting all those problems fixed, I made some fan braces from some of the remaining offcuts of the soundboard wood, and chiseled notches into them to fit over the bridge patch:

 

Then glue them in. I couldn't think of any way to safely clamp them with the bridge in the way and without damaging the very soft soundboard, so I just did them one by one, held with my fingers for 15-20 minutes until fairly dry. Good time to watch a movie Then carve to whatever seems like a good shape:

 

Of course, adding stiffness to the top raises its resonant frequency, which means that the back is now out of balance... so I added some braces to it as well:

 

...and it didn't change. The mass of those braces is enough to cancel out the frequency effect of the added stiffness. Chisel 'em off, try another approach. I planed the peak off of the middle cross brace, and glued on another piece of spruce to make it taller than it was. Carved that back to triangular profile, and the frequency is up in the range I was after

 

No more construction pictures after this, because none of them were particularly interesting. The remaining steps are: Glue the back on (same as before), trim the overhang (using a chisel, finger plane, and scraper), round over the edge (scraper and needle files), and finishing.

 

Most back/side woods, including this ziricote, have pores that are kind of ugly amid an otherwise shiny and smooth surface, and thus are typically filled. The method I use is traditional for French polishing, using the same cheesecloth and muslin pad, but with pumice and alcohol on it instead of shellac. I've already given the wood a coat of shellac, so the alcohol dissolves that, rubbing the pumice grinds up some very fine wood dust like sandpaper, and since I'm pressing pretty hard, the mix of pumice, wood dust, and dissolved shellac gets squished into the pores, filling them up.

 

After that's done, it's polished just like the top using a fresh pad.

 

And here is the finished product Hopefully this many large pictures won't kill the forum...

 

I could go on and on about little flaws, but overall it turned out quite well. The sound with the added bracing is not quite as good as it was, but certainly not bad. Here are some new recordings of my random playing:

http://deku.rydia.net/guitar/crystalheart/ImprovE_2014Jun24.mp3

http://deku.rydia.net/guitar/crystalheart/ImprovAm_2014Jun24.mp3

http://deku.rydia.net/guitar/crystalheart/ImprovD_2014Jun24.mp3

 

So that's that! Thanks to everyone who's followed this build log Hope you had fun and learned something about how guitar family instruments are constructed.

 

Here's the DeviantArt page for this: http://dekutree64.deviantart.com/art/Crystal-Heart-ukulele-463217511?ga_submit_new=10%253A1403643020 Go check out my plushies and stuff on there too

Edited June 25, 2014 by dekutree64

[Frith is Magick 1,471]

Following this build has been quite interesting, and the product turned out quite well (even if my opinion in the matter counts for very little). Your other instruments on DA are also pretty cool (that harp ukulele has quite the sound). I'd definitely be interested in following another build log if you're willing to do one for your next project. Just out of curiosity, how long have you been building ukuleles?

[dekutree64 713]

Following this build has been quite interesting, and the product turned out quite well (even if my opinion in the matter counts for very little). Your other instruments on DA are also pretty cool (that harp ukulele has quite the sound). I'd definitely be interested in following another build log if you're willing to do one for your next project. Just out of curiosity, how long have you been building ukuleles?

This is my first regular nylon string ukulele, but my first guitar was a steel string in 2010, and that's really not much different

 

I have a couple other open build threads that I may or may not be getting back to updating as I work on the projects:

http://www.luthiersforum.com/forum/viewtopic.php?f=10130&t=41908

http://www.luthiersforum.com/forum/viewtopic.php?f=10130&t=37136

 

I'm also back to working on the sequoia topped guitar that this ukulele's top is made from the offcuts of. I started it 3 years ago, before I started doing build threads, but I may make one for it as well, especially if it ends up being the one that I work on the most of the current bunch. I'm trying to finish all the builds that have fallen by the wayside in favor of new ideas over the past few years

 

And I do love that harp uke Unfortunately, it is a bit under-braced, and developing problems now at 2 years old... I'm going to try switching it to lower tension nylon strings and see how it sounds. Here's the old build thread for it: http://www.luthiersforum.com/forum/viewtopic.php?f=10132&t=35031