Build Log for #002

saltytri

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Build Log for #002 - Finished!

There was recently a very interesting discussion started by Pete Howlett on the subject of peer review and this sub-forum. As a beginning builder, I’m not going to offer anything to the peer review discussion because I’m not a “peer.” With respect to the use and usefulness of the sub-forum, it has certainly been of immense value to me and, I’m sure, to other inexperienced builders. For aspiring builders, there is a practically endless vein of useful information already in place and, also, an opportunity to get constructive criticism from the experts to improve our projects. As someone else observed, there may be the occasional “attaboy,” and no one doesn’t like praise, but most of us would rather get useful advice about our materials, tools, and techniques even if some criticism is involved. So, I’m going to toss up a log as my second build goes along. I hope that it creates a vehicle for input from others and, perhaps, an inspiration for other beginners to take the plunge.

Since my first build was a concert, I thought that it would be a good idea to do another concert for the sake of continuity. In reality, the first few builds are less about the final instruments than about 1) making tools and jigs, 2) learning about tonewoods and other materials, and 3) learning how to do things in ways that are consistent with good lutherie practice and still compatible with your own skills and the available tools.

Collecting wood has been a lot of fun. One of the pros recently mentioned that amateurs have a freedom that the pros don’t. We can use woods that don’t turn up much in commercially mainstream ukuleles because we don’t have to conform to what customers will accept. This opens up a wide range of potential materials that work fine but aren’t koa or Honduras mahogany or the other classic choices. There are only two hardwood outlets within an hour-and-a-half drive so pickins’ ain’t easy but it’s still amazing what turns up from time to time. Last week, the hardwood place in town got in a new load of walnut and right on top of the stack was a seven foot 1x5 board with nearly vertical grain through most of it. Someone had thoughtfully put it on the top of the stack for me to find so it got taken home. After resawing a couple of slats and thicknessing them on the drum sander, the hot pipe was fired up and all went well until the second side snapped. This was a real surprise because I thought that I was taking it slow, but that’s how you learn the feel. Luckily, the good piece was back-to-back with the next surface on the board so a matched replacement was sawn off and the sides were completed.

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Although this is only my second instrument, I’ve tried bending a number of woods and have found that walnut takes to bending well enough to be near the top of the list of beginners’ woods.

There is a shop down the road that uses Port Orford cedar to make planter boxes. The guys there kindly gave me some 2x6 drops to experiment with. Each piece is enough to make a laminated neck. An eighth inch of walnut was laminated down the middle with epoxy.

All other gluing on this instrument has been done with hot hide glue but it seems like epoxy is a better choice for neck laminations to avoid water absorption and possible warping. The dowels were used to hold the three pieces in position so they wouldn’t slide during clamping. Of course, they are removed when the neck blank is sawed to the correct profile.

The Wagner Safe-T-Planer has detractors and supporters and it won’t add much if we debate its virtues here. I will say, though, that it works wonderfully when the work piece is moved beneath it on a sliding table. I’m lucky enough to have a metalworking mill to do this job but the same could be accomplished with a cross-slide table under a drill press.



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I've tried a couple methods for truing up edges to glue tops and backs. Sanding with a vertical guide over sandpaper stuck to a piece of glass works but planing with a shooting board is quicker, truer and cleaner.

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After making some mistakes when gluing plates, I've settled on a one-two approach. The tape method allows the hot hide glue to be applied and the joint closed quickly. The wedge method then comes into play to insure continued, firm contact and flatness. The oak 1x2 down the middle was chosen because it has a substantial bow that helps to apply pressure at the center of the plate.

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The resulting joint is pretty well tight.

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Here in Oregon, we can buy perfectly quarter sawn western hemlock all day long at Home Depot. Brad has commented on this and has successfully used hemlock in his super-economy build for kids. The grain is usually very fine but I stumbled on a QS 1x12 plank with grain that looks more like cherry (cherry on the left and hemlock on the right, with the contrast boosted to better show the grain).

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The hemlock is stiff and has a nice tap tone, so we'll see how it sounds as a top.

Now for a question. A 15' dish was used to contour the sides for the radiused back.

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I’ve read that a good way to avoid problems with the neck and fret board angle is to radius the top only below the sound hole. How is this done? How do you get a gradual transition between the flat area and the radiused area?

Thanks and best regards to all,
David
 
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Here's how I answered my own question. The top rim of the sides was first sanded flat. The upper half was taped off and the lower half was sanded in the dish with a piece of heavy paper under the upper half. Pencil witness marks were put on the rim near the waist and the lower half was sanded until the marks were gone almost to the waist. The tape was removed and the sanding continued right to the end of the witness marks and a bit past with a little rocking motion to create a smooth transition between the upper and lower halves. This may not be the best or most efficient way of radiusing only half of the top but it works.

In retrospect, the tape step wasn't necessary but caution was a good idea at the time.

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Solid linings were bent out of Honduras mahogany. This worked out fine except that they are a bit more trouble to glue in place. They have to go in in one piece per side and there is a lot of clamping to be done quick.
 
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Thanks, tonewood!

Cutting a sound hole on a mill is way overkill for accuracy but that's not a disadvantage. It certainly is a convenient way to do this job. There is a Proxxon tool lashed to the mill head because the mill only goes to 3000 rpm, which isn't enough for little router bits in wood. The rotary table insures a perfectly cut hole.

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This afternoon was spent developing deep respect for people who do detailed rosettes. This was the second effort. The first was thoroughly botched mess of wood and CA and had to be completely routed out. The primary wood is walnut, to match the body. The black and white are wood purfling strips from LMI.

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Thanks, John.

The name goes back to my seafaring days. I'm not quite as salty now.
 
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Number 2 is coming along. Next, I'll shape the back braces, trim the top and then get to work on fitting the neck.

For the life of me, I can't see how it's possible to work at the speed necessary to glue a top on with HHG without getting glue in places where it shouldn't be. Lots of experience, I guess.

Another lesson learned: The sides were raised in the mold to provide some clearance while gluing the top. The turnbuckle cauls in the bouts weren't tight enough and as the go-bars were put in place, the sides slipped down in the mold. This released the pressure provided by the go-bars, so I quickly removed them and the top. When I used water to help clean the rapidly gelling glue off the top, it went "potato chip" on me because of the moisture. It was pretty alarming but I put the top onto the radius dish and weighted it well. The next day, it was fine, thank goodness.

Of course, some things do work out as planned. With the neck squared up to the body and the fretboard in place, the basic relationships for a good setup are right on target: a straight edge from the 1st fret to a 1/8" rod at the 14th fret ends up yielding a saddle height of .40" - sweet! And the lower end of the fretboard sits flat on the top.

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Time to whip the neck into shape. First, a 1/4" diameter carbon fiber tube was epoxied into the neck for insurance. The neck will bolt on with a barrel nut and a #10 screw. Hardware store barrel bolts take 1/4" screws and are made of steel. To "add lightness," every little bit counts, so I made up a few out of aluminum and tapped them for 10-24.

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A fret caul was made to mount in the drill press. I got my first taste of ebony and it really took some careful work to get the frets pressed in straight. It helps to run a little triangle file along the slots to open up the tops a bit so that the frets can get started straight down. In the end, the frets seem to be pretty even and it looks like there won't be a huge amount of leveling required once the fretboard is glued flat.

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After the first concert, I altered the mold to make a flat just wide enough to seat the neck. This makes a lot of sense to me, as perfectly fitting a neck to a curved surface isn't easy. A hole was drilled perpendicular through the heel block to match the approximate location of the barrel bolt in the neck.

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Since I know machine work better than lutherie, I tend to fall back onto machinists' tricks to solve problems. This nifty hardened steel tool is commonly used to locate a hole to match an existing hole. They come in sets in 64th inch increments but it is easy to make one to suit a particular purpose like this by turning a piece of brass rod in a drill press.

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The neck is aligned in the correct position against the body and the pointed rod is pushed in a bit to mark the place to drill the corresponding hole in the neck.

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I couldn't decide whether to do 12 or 14 frets to the neck so I settled on 13 like a Koaloha. The fretboard was kept short, no longer than the heel block that is under it. I'm not a good enough player to do dazzling things way up the fretboard and leaving it short may allow the upper bout to contribute more to the sound.

Shaping the neck will come next.
 
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Its coming along very nicely, and should turn out a treat.

Don't know if you're aware of issues with CA and softwood tops, but it bears mentioning in case others reading this don't. When using CA on softwoods like spruce, western red cedar, red wood etc. always seal the surface with something like shellac, lacquer or even hide glue. Otherwise the CA will wick up the end grain quicker than a rat going down a drain. Staining the top in a way that no amount of sanding will save. It's a very common mistake, and one you don't forget quickly.

The other tip about using HHG for attaching any large surface that you are having trouble getting around will make it dead easy. It involves using the very thing that makes using HHG a treat. It is reactivated with moisture and heat.

First off you need to size both mating surfaces with thin HHG glue. All you are doing is getting a very thin wet surface. Then let completely dry if you like while you get your clamps and wits about you.

Now if you're not confident in doing the whole plate in one go, you can do it in small pieces. Start at a point that makes sense to you. Like at the neck block if you use an alignment pin or your upper bout with the transverse braces fitting into the linings. Apply full strength glue to that area and clamp up.

Now that's out of the way you need a pallet knife to dip into your glue and then slip that between the top and linings. Spreading a layer of fresh hot glue. Remember it doesn't take much. You've already got glue in there when you sized the parts. Do a short stretch and clamp up. Continue around the perimeter until it's all complete. And it doesn't matter how large the instrument is. This technique works just the same on a uke as a double bass.

Turn off the glue pot and grab a beer while you stand back and admire your handiwork. And don't forget to give yourself a pat on the back.

As an aside, this is also how you accomplish some types of repairs where HHG was used originally.
 
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Those are both great tips - thanks, Allen! I bought a thin pallet knife today and I'll try this method when the back goes on. It makes perfect sense to break the job down into manageable segments.
 
The method used to glue the back was adapted from Allen's advice. Both surfaces were sized with thin glue. The upper bout was clamped to the sides and the back was lifted about a quarter inch so that glue could be applied. After the lower bout was clamped, the upped bout was raised a bit and glue applied. Also, the warm palette knife was slipped in the joint as far as it would go toward the lower bout to make sure that glue got all the way into the joint. Doing it in halves gave me enough time to feel comfortable.

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After the glue was set, final fitting was done to the neck and the body was sanded. Next, the neck will be sculpted to form.

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Love the details! I plan on trying my hand at building a uke this year & posts like these are so instructional & motivational as well.
 
Go for it, Gmoney. The rewards far outweigh the frustrations. I see that you're on Brad's list also. I spent a dizzying afternoon with him last summer getting a big dose of practical lutherie. At that point, the plan was no more than to acquire one of his instruments but the building seed took root. I'm looking forward to having his work to play and also to copy, as that is a tried and true way to learn.

Hot hide glue certainly has a discouraging reputation. Someone commented here recently that he's getting good at it after twenty-five years. I'm learning that it really isn't quite that grim. It does take more time and care than glue-in-a-bottle and there is no point in second-guessing those who decide that HHG isn't worth the trouble. Both are valid preferences but I'm having fun for now with the more traditional approach.

Thanks for that idea, Liam. Now, I've got to figure out how to make a heated palette knife.
 
Thanks, Gyozu! That site is a goldmine of ideas. It made me realize that the solution is my under my nose. Stay tuned.
 
With a bit more practice and confidence you'll find that getting around a uke in one go is quite easy. But there is nothing wrong with doing the glue up in manageable parts either.
 
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