Finishing and the Little Bits

With the neck and body in one guitar-like object at last, it comes time to start finishing up - which means constructing and detailing the little bits (truss rod covers, fingerguard/pickup assemblies, tailpieces, bridges) and wood finishing.

Regarding the finishing: I don't have a spray booth, but I decided to do a traditional full-gloss lacquer finish for these guitars. I used Belhen's Stringed Instrument Lacquer in aerosol cans, which worked better than I thought it might, and sprayed with what spray equipment I have at hand for final coats. Here is the full schedule of finishing, which will partly explain why I haven't posted lately:

• Wood filler on mahogany and cherry, and sand to 400#
• 2 coats lacquer and sand to 400#
• 3 coats lacquer and sand to 400#
• 3 coats lacquer and sand to 400#
• 3 coats lacquer and sand to 400#
• "dotting" imperfections, sand dots to 400#
• 3 coats lacquer
• wait 2 weeks
• wet sand to 600#
• polish by hand with medium and fine colortone abrasive
• final polish with colortone swirl remover

I taped off the maple bindings for wood filler.

Smearing on and smearing in the Timbermate water-based wood filler. 

Sanding off the wood filler. This stuff dried hard as a rock, and it took three days to sand it off. I had to be careful: too aggressive, and I could sand deeper than I wanted, less aggressive, nothing much happened. It's a good product, but next time I would squeegee it in, leaving a lot less on the surface.

First coat of varnish. The first couple of coats soaked right in. I sanded, then more - soaked in again. It wasn't until about 8 coats that I started to see anything "building" as a finish. Partly, I think, it was the aerosol cans, which don't deliver quite as much product per coat as regular spraying. I think the cans need a thinner product inside to spray properly, so they can still work when the pressure is so low towards the end of each can.

My son Brendan soldering the volume and tone controls to the Benedetto humbucker pickups mounted to the fingerguards, in the Psychoacoustics lab at Skidmore college, from which he graduated (with honors, ahem) a week or so after this photo was taken. Behind him is his beloved 3D printer. For the pickguards, I laminated curly cherry veneer onto solid cherry - same veneer as the flip side of the headstocks.

Fitting the ebony bridges to the curve of the tops. This was remarkably easy - just a lot of small stroked against 80 grit paper. I decided to do this midway in the finishing, so that any harm to the tops could be "rubbed out" - but no problems arose.

Pickguard/finger rest and ebony tailpieces. Because these are really acoustic guitars, what little electronic components there are stay separate from the body and unobtrusive. The Benedetto humbucker pickup is mounted to the floating fingerrest, and the volume and tone controls are mounted unobtrusively beneath it - just a liver of each dial shows.  Brendan wired a plug to the electronics which mates with the endpin jack, for easier disassembly and repair. I took a shortcut ith the ebony tailpieces, buying predrilled benedetto blanks, since my drill press is still shot from shaping the tops and backs. As it turns out, the predrilled, rough ebony blanks cost me less than buying a decent piece of ebony would have, so I figure I'm ahead of the game. I shaped the tailpiece blanks, and finishes the tops in wax alone, to match the fingerboards.

"Dotting." On the adv ice of Harry Becker, local luthier, I took a few days to "dot" all the minor cavities and imperfections in the finish with tiny dabs of lacquer, applied with a tiny pointy brush. I sanded these down flush before the final coats of lacquer.

Truss rod covers. I laminated a thin piece of burl (same backyard cherry burl as the headstock on the right in this photo) to a thin piece of maple for contrast, then inlaid a small MOP piece and shaped them.

Final coats of lacquer applied - waiting 2 weeks for it to evaporate to the extent that when I polish it it will stay polished, rather than shrink more (which would produce grain lines).

Wet sanding with 600# paper. A long, slow process, to get the surface dead flat for polishing. You can see the lacquered but not sanded surface at bottom right, the sanded but not shiny surface upper left.

Polishing. This was incredibly satisfying. From the dead flat surface arose a gloss finish. I used Colortone medium and fine abrasives, hand rubbed with white felt pads, followed by Colortone swirl remover and cotton cloth.

Final polishing - bringing up the gloss.

A finished back.

Finished cutaway on Brendan's guitar

Bottoms. Brendan's guitar (left) has gold hardware, mine is silver.

F-hole detail. Subtle, but I'm pleased.

Finished headstocks.

Finished backs.

Ready for Harry Becker to do setup. In a few weeks Brendan and I will each have a ne guitar!

Putting it all together

This went far more easily than I had feared.

Final alignment. I tapped the neck as far down into the dovetail oint as it would go, and noted whether the neck and body were aligned straight. As it turned out, both were right on the money. There was a little bit of play in the upper end of the joint, so I glued a piece of mahogany veneer to one side of the neck joint and filed most of it off until I had a tap fit all the way down.

Final fitting. You can see the veneer piece I added on the left side of the neck joint, which was then filed down. 

To get a perfect fit between the part of the neck that rests on the top of the body, I reinforced a bit of carbon paper and slid it through the tightened joint repeatedly to find high spots, which I snicked away with a sharp 1/2" chisel.

A high spot from the carbon paper. This was an early round of fitting - eventually most of the surface area was fairly evenly covered with carbon spots, after about the fifteenth iteration of slipping in the carbon paper and snicking off the high spots.

Getting ready for the big moment.

Glueup! 

Once the necks were in place, I leveled, dressed and polished the frets. I was pleased to see a really straight neck on both guitars, needling very little removal of metal from the fret crowns.

Fitting the nuts. I removed the veneer and binding right down to the maple.

To get the best fit, I dirtied up the bottom of the nut with soft lead from a carpenter's pencil, then wiggled it back and forth in its slot, again snicking off the high spots, this time with an 1/8" chisel.

Finished nut fit. Pretty good. Left a lot of bone there for stringing later.

In the white, ready for finishing.

Now I see why they call it "fretting"

I waited to set the frets until after I rough fit the necks to the body, and also did all the final shaping and smoothing before I set any frets. I made an error in judgment right from the start here, which gave me a genuine klong (that's a medical term for a rush of shit to the heart). I had to scramble to get back on track, but everything turned out fine.

Flush-cut fret nippers, home made. I took two seldom-used wire cutters and ground their faces halfway through the "blades." The smaller one on the left wasn't robust enough to cut the fret wire at all, but the other one worked fine. Saved about $30 with this, I think.

First, I made a complete set of frets for both guitars, without bending the wire to any radius, undercutting for the binding and some overlap to trim. I thought the curve was so slight I would have no problem pressing them in to fit the curve. Boy, was I wrong. 

Before I started actual fretting, I scraped the slots to remove any crap or glue slop from the bindings. To do this, I ground a hook in a dull shop knife blade, and ground the thickness down a little. This worked great.

DISASTER. The first fret I placed (fret # 1 on my guitar) did NOT bend to the radius of the fingerboard. Or rather, it almost did, but the extensions with the tang removed stayed straight, leaving a gap between them and the fingerboard. I tried to curved them a bit, to no avail. So I removed the fret, and this is what happened.

Having recovered from the klong, I made a little groove-filling shim of aluminum sheet and wax paper, and dribbled in some of than wonderful black epoxy I used for the inlays. Next morning, I sanded the whole fingerboard with the sanding bar, and the holes were practically invisible.

But back to fixing the disaster. I had 43 nicely cut straight frets which would not work unless I could come up with a way to radius them. Here it is - my "fret fixer." The fingerboard is a 12" radius. I guessed at half that (6" radius) for a press to curve tham, figuring a lot of springback. The lower part has a slightly oversize slot for the tang, the upper part has a round mortise for the head. Insert a straight fret and...

...clamp it in the vise. I got really lucky here. Look at all those frets I was able to salvage.

Here's one of the newly-fixed frets, straight from the fret fixer. I'm holding it up against my 12" radius sanding bar to show the slight extra curve, which is just what I wanted. 

From that point on, it was just a matter of pressing them in, with the nifty Stewmac arbor press mounted in my drill press. I added a little bit of titebond, applied to the fret with a toothpick, each time, following Bob Benedetto's advice (which I should have followed about radiusing the frets in the first place).

Here's the fret installed over that "disaster" chipped ebony. It's hard to spot the repair.

I trimmed and filed the ends of the frets, and thus concludes a thorny chapter of this build.

Shaping and Fitting the Necks

I was worried that the dovetail joints might be too tight, too loose, whatever. As it turned out, everything was pretty straightforward.

Sanding setup for the necks. I have a great vintage stationary belt/disc Sander, and it theoretically has dust ports, but they only capture about 30% of the dust. So I posted a fan in the window and moved the tool near it. Between the fan and the dust ports, it wasn't too bad,

With the tip and flat of the belt sander, using a new 40-grit belt, I shaped the neck to rough dimensions, leaving a little for hand rasping and sanding. The bottom one is roughed out, the top one is waiting to go.It was relatively easy to get decent proportions. I love the V figure that emerged as I rolled the headstock into the neck. 

I used a Nicholson rasp to bring the necks to their final fair shape. I stopped every few minute to remove the neck and feel it for symmetry. Part of the task here was knowing when to stop.

Laying out the fit of the neck to the body. This was a difficult measurement. A straight line along the centerline  of the fingerboard should fall exactly 3/4" over the top of the body at the location of the bridge. I placed the neck in the body and measured how far it needed to set down on top of the body to accomplish this. For one guitar it was about 1/4", and for the other it was about 3/8". Both seemed within specs. Next, I scribed both sides of the "waste" portion of the fingerboard extension, and marked it for cutting. I could only cut some of it away by sawing, leaving a lot of trim and "inside corner" work around the dovetail.

Trimming the waste for a rough fit. A sharp chisel, small japanese saw and shop knife let me trim away enough for a rough fit after bandsawing the waste, then back to the belt sander to shape the "floating" tip of the fingerboard.

The neck on the bottom is ready for a rough trial fit, the one at top is uncut.

After I got a decent rough fit, I made and added a heel cap to each neck made of curly red maple with a mahogany veneer separating it from the other maple at the "binding" line of the back.

Glory work! Fingerboards and Inlays at last.

I have been looking forward to seeing the necks take on their final "facial" appearance, and I'm pleased with the results.

First I needed to sand the excess neck maple away from the headstock bindings. To do this, I made a sanding jig the exact radius of the concave sides, and spray mounted successively finer sandpaper to it. If I hadn't done it this laborious way,  I'm sure the curve would never have been just right, and this would be really obvious to the hand and eye.

Sanding the other headstock side curves was easier, using a drill press sanding tool with a few grits of paper. That's a vac on the left, keeping the room just a little less messy.

Well, I had a heartbreak here, but it's going to be OK. My drill press quill has gotten a lot of side movement in it, from using the Wagner Safe-T-Planer. So when I drilled the tuner holes from the back of the headstocks, they drifted all over the place laterally. I just about shit myself. Anyhow, I repaired the drill press, plugged the holes (with maple dowels), and redrilled them. Fortunately, the tuners have washers on the top, which cover all the visible maple except for one hole on each headstock, which I patched with a cherry or cherry burl "Dutchman."

I bought preslotted ebony fingerboards from Stewmac. They're beautiful. They come with parallel sides, and needed to be tapered, so I made a simple tablesaw jig. Here's the first cut on each.

For the second, final cut, I reversed the fingerboard in the jig, and added the offcut from the previous cut, plus a spacer.  I had to do it this way because the boards had to be tapered from each side, relative to the fret slots.  Worked fine.

I used a special caul to glue each of the fingerboards. You can't see them in this photo, but there are three alignment pins through the caul and fingerboard into the necks, to make sure the fingerboards don't slide under clamp pressure. 

I used maple and cherry for binding the sides of the fingerboards. I clamped the bindings hard against the fingerboard, then used superglue to weld the wood together. The cauls here are covered in wax paper. I use "Cut Rite" brand wax paper because the name suggests it should be used in woodworking.

I mitered the binding joints at the base. Here is one being clamped for gluing.  I left the bindings just higher than the top surface of the radiused fingerboard, so I could use it as a stable base for my mini router when inlaying.

First inlays: diamonds on my neck. I used .3mm mechanical pencil to draw alignment guides, then traced around each diamond with the pencil as I held it in position. Than I used a dental burr chucked into a Dremel Moto Tool with a router base. The black epoxy I mix will squirt up from the hole to fill those little cuts in the diamonds.

Mortises for the gold MOP inlays on Brendan's fingerboard. Same technique as the little diamonds, but a lot more ebony dust.

Here's how I made the pattern for the inlay pictures on the headstocks: First, I scanned the headstocks and inlays actual size, combined them in Photoshop, and printed them on adhesive label paper.  Then I peeled the backing off the prints, stuck the in their spot on the headstocks, and cut away the "inlay parts" with an exacto knife.

When all the pieces were cut out, I emptied my shop's pencil sharpener onto a sheet of paper and blackened my finger with the graphite, rubbing it in to the stencil. The graphite sunk onto the knife marks, leaving a clear pattern for me to cut.

The completed headstock pattern, ready for routing and cutting.

Since I wanted the best fit for these inlays, I only used the router to waste away the insides where I could. This was helpful in establishing the proper depth for the mortises. I cut the rest by hand with tiny chisels I made by sharpening jewelers screwdrivers. This was tedious.

I mixed cherry dust with epoxy to glue the 34 inlay pieces. 

I used black epoxy on the fingerboard inlays. I then let the whole thing cure for a day before sanding.

Sanding the fingerboard inlays took some time, but went very well. I purchased a 12" radius aluminum sanding block from Stewmac - the only expensive tool I bought - but it was worth every cent. I spray-mounted 60 grit paper to the block and used it to grind the shell and epoxy down to the ebony, then used 80, then 100, then 120, then 150, then 180, then 220, then 400, the 600 grit paper on the block to get a decent scratch-free surface.. 

Cutting waste wood from the sides and end of the fingerboard on the bandsaw. I taped blocks under the neck to support it during the cut,  and left a little extra next to the bindings, which will come off when I shape the necks, starting Monday.

Here are the necks in their present shape, ready for shaping, fretting, and attaching to the bodies.

Finished headstock inlays. You can see the patches over the two ill-drilled holes, which won't be noticed after the tuners and their washers are installed.