All posts by pmccombs

SCVMW 2015 – Wednesday

It was a busy morning with a couple of lectures/demonstrations. The first came in response to my question about placing the corner purfling channel. Michael showed me how Stradivari pointed his purfling toward the lower quarter of the corner, and not in the middle as I had planned to do:

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You can see in the above photo how my original line was nicely centered, but Michael’s more forceful gouge mark demonstrates where the line of the purfling should really run. This gives more room for the “bee-sting.”

I used this long knife to score the purfling channel, then I removed material with the purfling pick.

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Since my knife blade is so symmetrical, I lost track of which side was the sharp one and earned my first cut at the workshop.

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Here is a picture of my purfling channel, all cleaned up:

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Some makers wait until after the plate is completely carved and sometimes even until after is has been installed on the ribs before doing this work. Waiting until the end seems a more natural approach, since purfling is, after all, finish work. But I do the purfling immediately after establishing the edge thickness.

After the channel is cut, I bend the purfling and set them in place to test for fit:

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Once I’m happy with the purfling in general, I spend time mitering the corners and lapping the pieces at the upper and lower bouts. The lap joint is nice, because that way you don’t have to measure the upper and lower purflings exactly.

At last, the purfling is installed. Note how the purfling overlaps at the top and bottom of the plate. I’ll just trim that flush tomorrow and you won’t be able to tell there is a joint there at all:

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Here is a close up of my corner work. It’s not up to Stradivari standards yet, but it is quite serviceable and will clean up nicely once I get the scoop in and scrape it all down (and add any necessary fillers):

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As you can see, my “bee-stings” are not too bad at all.

Next, I’ll carve the scoop and then work with the templates to get¬†the plate down to the right dimensions and proper arching. At that point, it will look fairly finished, except for the hours and hours of scraping required to get all the little bumps out.

Also today, Michael and I discussed bass bar measurements and how to finish that particular piece in a deliberate and systematic way. In the past, I have simply imitated what I have seen other bass bars to be like, not understanding the system employed to reach a consistent and rational result. Michael was quite happy with the fit I got for my bass bar–since that is a difficult project to accomplish correctly–but I needed additional instruction on the shaping of the bar after it has been successfully glued to the top. I had hoped to get around to actually doing that work today but did not have the time.

There was also a good demonstration of re-setting a neck. Michael’s system for finding the exact center line, taking into consideration the idiosyncrasies of the f-holes and so forth, was quite involved and lasted over an hour. I have not taken such care in the past and will have to pay closer attention to this aspect for future builds. In practice, the system was much simpler than the explanation. ūüėČ

In general, it was quite a productive day, and I have met a lot of extremely talented luthiers outside of my interactions with Michael Darnton. The Claremont workshop attracts the finest talent from across the world, and it’s a lot humbling to rub shoulders with them; to see and handle real instruments made by Stradivari himself, or by Guarneri del Gesu (the Jackson Strad and the Sloan del Gesu have been at the workshop every year since I began attending). I have a feeling that relatively¬†few violin makers get such opportunities during the span of their careers.

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SCVMW 2015 – Tuesday

Well, it’s time once again for the Southern California Violin Makers Workshop, hosted by Jim Brown and instructed by the prodigious Michael Darnton of Darnton & Hersch.

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This year, I’ve brought a couple of projects to work on. I’m fitting a bass bar and carving a violin neck and scroll.

Here is my bass bar in progress:

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Michael’s advice for the bass bar is to carve it well enough that you don’t have to press it down to get a good joint. It should be good enough that it could be attached¬†with a “rubbed” joint, although we clamp bass bars¬†traditionally.

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The bass bar stuck fast to my top after only two short rubs, then I clamped it for the night. I’ll carve it down tomorrow.

My other project is this scroll:

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Pictured above is the volute as it looked when I arrived at the workshop, and I was rather unhappy with it. The profile reminded me of a wedding cake with layers of even thickness, with a shallow slope that lacks in elegance.

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In the above photo, you can see how I have begun to put a more pronounced angle on the right side of the scroll.

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The scroll is pictured in process and is starting to look better. In the photo below,¬†it is pretty much finished (for the record, this piece of hard¬†maple was¬†insanely difficult to carve. I’ve never had one give me so much trouble! It tore out like crazy, and I could never figure out the run of the grain. Look at all the flecks in it, though.):

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Michael said this looks pretty good and that I’ve got the right feel for it. That’s a good compliment. However, he also suggested that I might further improve my work by making the scroll¬†a bit smaller. The problem is that we use templates and tend to cut to the outside of the line, which is outside of the template, which is often itself cut ever slightly larger than necessary. These little things add up to make a larger reproduction than what was intended. This scroll is almost 3mm taller than Strad’s version, and the throat gap is a bit too pinched.

Still, this is good quality carving and quite up to snuff for a violin’s head. 3mm would be a fatal¬†discrepancy¬†in other, less forgiving areas; but a scroll is mostly pure aesthetic, and this one looks pretty nice.

One thing that I find I am developing as I carve each new scroll is a technique for the gouge. I used maybe three gouges on this scroll, and I find that, in addition to gouging, I use them to slice like a knife and even to scrape. I can get a lot of mileage without having to switch to another tool.

Tomorrow I may have time to dove-tail this neck and prepare it for setting. I left my block planes at home though, so I’ll have to borrow some. I also hope to do some purfling and arching, if there’s time. I made up new cycloid templates for this project, and it would be a pity if I didn’t get to use them while I’m at the workshop. I need Michael to check my corners, though. Those are still dreadfully difficult.

Featured on Stew-Mac’s May 2015 Catalog!

The May 2015 edition of StewMac’s catalog features one of our guitar projects. This is one that Aly built and painted–the same one she performed on at Carnegie hall with Wayne Bergeron and Caleb Chapman’s¬†La Onda Caribe√Īa.2015-05-10 16-30-08

Here it is in action:

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How to Make a Color Decal with a White Background

I’ve had some questions about how I made the decal for my latest¬†build.

You can print your own decals if you have a color inkjet printer. All you need is the Testors waterslide decal kit, which includes paper and a little spray can with an ink bonding agent in it. Get the clear decal paper.

The only problem with the inkjet decals is that you can’t use white in your design, unless you plan on applying the decal over a white background. You can get the opaque decal sheets, but that only works if your design isn’t intricate and has no transparent bits.

I first tried spraying a solid white to see how it would look, but I didn’t care for it at all:2014-10-09 07-44-14-1

To solve the problem of no-white-ink, I took a simple approach that involved ¬†a magnifying loupe, white Elmer’s glue, white acrylic enamel paint, a small, pointed-tip paintbrush; tweezers, a paper towel, a cotton swab, and a small¬†dish of water.

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I soaked my printed decal and removed it from its backing paper. I let the decal dry out, then I turned it over onto its face. With the assistance of the magnifying loupe and the small paint brush, I was able to paint in the white areas reasonably well. This is pretty intricate work and not easy to do perfectly.

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Here is the painted decal:

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After the paint had dried, I diluted a small amount of Elmer’s glue and applied it to the headstock of the guitar with a cotton swab.

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Place the decal over the glue and carefully rub out any bubbles. 2014-10-12 13-49-38

 

Once everything was dry, I applied the clear coats. I sprayed probably 16 coats, sanding between applications with a 400-grit paper until the raised edges of the decal completely disappeared.

Be prepared to ruin several decals before you get this right! Here are some of the problems I encountered:

  1. Bad printing settings. You may need to create a custom paper size in your computer’s print settings in order accommodate the half-sheet decal paper. I also had to select the “photo paper” option to get the best ink coverage. I didn’t use the antiquated Testors decal app to create and print my decal, I just converted my existing graphics to a PDF and let the PDF reader do the printing.
  2. Defective decal paper. One of the sheets I used was too thick and wouldn’t¬†separate easily from it’s backing paper,¬†no matter how long I soaked it. I finally gave up and tried another piece from a different package. This¬†made a big difference: The new sheet¬†was thin and slid easily from¬†its backing paper¬†after only a few seconds in the water. Hopefully you don’t run into this problem, like I did. Waterslide decals should be fairly easy to work with.
  3. The amount of ink bonder needed to get a durable decal. If you spray too much bonding agent, it produces a pink shadow around the decal and makes the colors run, while too little will result in a decal that easily smudges while it’s being applied.

 

12th-Fret Inlay

Here are some pictures of the inlay work on my most recent guitar project.

I used Inkscape to come up with the design:

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While the design looks good, I found it exceptionally challenging to cut this from mother of pearl. I broke half a dozen saw blades, and it was almost impossible to achieve the precision of the drawing at the small scale needed.

Still, I was fairly happy with how the inlay came out:

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Here it is inlaid, and the gap has been filled with wood filler:

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This is the same design I used on the other two guitars in the series. The first one was cut from a cracked piece of curly maple that was originally slated for a violin. That was not too hard.¬†My¬†second attempt was also cut from MoP, but it didn’t come out quite as clean as this one.

I cut small triangles from scrap pieces for the remainder of the fret dots. No two came out exactly the same, but I arranged them in an order that I though made the most sense. Here is the result:

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Custom #3 in the Box Elder Series

 

 

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(Click for larger size)
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(Click for larger size)

For this build, the customer had brought me a chunk of knotted box elder burl roughly shaped to a Gibson Firebird V body. I ran the piece through the thickness planer and filled it with epoxy to stabilize it, and I fine-tuned the contours. Electronics cavities are free-hand routed.

I built up the neck from a piece¬†of flame birch and used a rosewood fingerboard with mother of pearl inlays, hand cut. The control covers and pick guard are carved from scrap pieces of box elder burl. The fittings are chrome and black, and I put D’Addario super lights on it.

The finish is of nitrocellulose lacquer, red fade over amber.

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More Photos

Here are some more photos of my recent guitar build.

These high dynamic range photos really show off the wood… and a bit of our backdrop too. ūüėČ

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Here are some pictures of the build process:

Raw Materials
A few of the materials for the “Strat” build. Pictured is the body blank, as I received it. The “Les Paul” guitar body was in a rougher state than this. Both bodies required some adjustments, and of course they had to routed for electronics and so forth. Also shown are some boards used to build the neck.
Truss rod rout
A neck board has been routed for the truss rod.
Fret Slotting
I’m working on slotting for the frets in this one.
Slotted fingerboard
Slotting is finished in this photo.
Fingerboard clamps
Fingerboard clamped to the neck blank
Neck shaping
Here the neck is starting to take shape.
Rough neck
Here is the rough neck. Note the truss rod peeking out from the heel.
Radiusing
Working out the fingerboard radiusing. I just wing it…
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Here the neck is starting to get rounded out to its final shape.
Neck mortisse
The neck pocket has to be routed so that the neck is angled at one degree for proper string clearance.
Neck Inlay
The neck inlay is coming together.
Finished inlay
Here is the finished 12th fret inlay
Fret work
In this photo I’m working on leveling and re-crowning the frets.
Here is the trade logo inlaid on the head stock. Pictured is one of my thin, oval scrapers that I used to scrape it flat.
Ready for electronics
I’ve installed the copper shielding tape and am ready to wire it up.
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Here the components have been installed. The guitar is ready for final assembly.
I made the Les Paul Neck from a single, thin board of curly maple. Many makers use a board that will accommodate the headstock angle without having to do this 16-degree joint. I couldn’t get a big enough piece of curly maple to do that method, though. Typically a less figured wood is used, with a fancy veneer glued to the face. Note the body blank in the background. I had to plane that down to the right thickness and do a lot of work on the body shape. A typical Les Paul is arched with binding, but not this one.
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I’ve made a template for the head. The truss rod rout is complete, the tenon is ready, and the neck is shaping up.
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The mortise on the Les Paul needs to be routed at a 3.5 degree angle.
Shaping the neck with rasps.
Shaping the neck with rasps. Note the routed body in the background.
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Test fitting the neck.
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Inlay detail and a look at the neck binding and side dots.
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Leveling the frets.
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Polishing the frets with “fret erasers.”