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Week 13: June 11 - July 22 (long week!)

I've taken a little family vacation, which has kept me out of the shop for a while! I'm back in the shop as of July 1, and bodying up the finish. Finishing has been a long, frustrating, but edifying procedure. It hasn't come out as well as I'd hoped, but I think next time it will come out better. There were effects that I can't explain, and some mistakes that I do understand. I'm glad I went with the French polish process, if only because I know I haven't inhaled anything toxic while doing it.

My first mistake resulted in the white flecks you can just barely see to the left of center on this picture, very short lines of white. This is pumice trapped in the pores of the rosewood back. I should have "cleared" the pumice by mixing it on the pad with alcohol before just starting to rub it in. This mostly went away over the course of rubbing and re-rubbing, but there are still traces of it. This is one of the aspects of French polishing where the authorities disagree; about all they agree on is that you do it with some kind of shellac. Some say put the pumice in tiny amounts on the pad, squirt alcohol on it, and then rub it on a small patch at a time. Others say sprinkle it on the wood, dampen your pad and go for it. 

Finish is beginning to have a deep shine a few sessions after the previous photo. This shine will come and go over the next several weeks as I rub it on, rub it off, and rub it on again.
From somewhere, a dark stain appeared under the finish. Nothing happened that I know of to cause this stain. You can see the edge of it near the waist in the upper left.
The bolt holes in the head block are handy for hanging the box to cure the finish.

I didn't fill pores on the neck, as I prefer a less slick finish here. I know this sounds odd, but a slightly sweaty hand can actually stick to a high-gloss surface on the neck. I did fill the peghead front, and polished that surface up as much as the body. The tape on the fingerboard was probably unnecessary since I wasn't spraying.

One thing I have learned well in this project is always to do dry runs of any operation involving glue. On the dry run of attaching the neck, I found that the neck bolts were in the way of the upper face caul. It needed another notch on the left in this picture.

Gluing down the fingerboard end so it won't rattle. The neck joint proper is not glued, but simply held together by the bolts. Most folks who put on necks this way will at least lightly glue the overhanging fingerboard down to the neck

This is beginning to be exciting. I cut the bridge shape out of the extra set of plans and traced it on the bridge blank. I poked a nail through the crosshairs on each peg hole on the plan, making laying them out a breeze. I also poked holes at each end of the saddle, which turned out to be much longer than the blank I had. No matter, as the saddle blank is plenty wide enough to handle the strings. I guess they liked a wide saddle on those older guitars.

Another clever use of the soundboard cleat. I glued two small scraps of spruce to the side to make a jig to hold the bridge blank while sanding the bottom flat. When I redo this text I'll count up all the uses this soundboard cleat is put to.


The Bridge Routing And Drilling kit. Underneath is a piece of pine with to scraps of spruce glued to it a a 1/8"-to-3" slope. This will orient the bridge blank at the proper angle to the front edge of the pine block to have it slide along a fence on the drill press while routing the angled slot for the saddle. To the upper left is the all-important scrap of ebony into which I drilled test holes with the 13/64" brad-point bit. I put a little rim on each hole with the countersink at right, and then reamed the hole with the #3 spiral-flute taper-pin reamer above center. This makes a snug fit for the ebony bridge pin also shown. Ain't it all just so complicated?

 

In order not to lose control of the bridge while routing, I drilled the peg holes and screwed the bridge down to the jig. This will quit working after a while as different bridges with different peg layouts are used, since the jig would get so full of holes as to become impossible to use this way. It would work well with bridges of identical design, but hey, I'm a hobbyist. I'll be making my next bridge four-dimensional or something. Anyway the jig took all of ten minutes to make and cost only a few pieces of scrap. As another brilliant innovation, I glued another small scrap of wood to the front and carved it down so that it would indicate the depth of the slot. I can then set the depth stop on the drill press with the bit just touching this scrap. The drill press fence is a straight piece of wood held down to the table with a couple of cam clamps. I waxed the front and bottom of the jig, and set the fence so that with the jig sliding along it, the bit hits the line of where I want the slot to go. The line is not quite visible on this photo, but the white marks I made to indicate the two ends of the slot are. With infinite time I would have set up stop blocks on either side of the fence to limit the travel of the jig and stop the ends of the slot, but I trusted myself to hit these lines by eye. 

The routing of the slot went beautifully, so now I'm ready to carve. With a black or dark brown piece of wood, it's important to have bright light to create shadows so you can see how the carving is proceeding. Here's how I set up the "carving station" in the vise at the end of my workbench. I'm a tall guy, so these lights are normally way up in the ceiling joists where I won't hit my head on them. When they are up there, however the inverse-square law means they don't shed enough light at bench level for carving!

I got a(nother) scrap of wood that's thinner than the bridge is wide, and stuck the bridge down to the edge of it with foam double-stick tape that's sold for mounting pictures to walls. It worked like a charm, holding it solidly but releasing quite easily when finished. I don't know how it knows when I'm finished. This method of mounting the blank holds it up away from the jaws of the vise so it's easy to get at from all angles to round over edges and so forth. 

I marked the line where the fist slight slope begins and another where the swooping curve leads down to the level of the "wings" at the ends. I also marked this swooping curve along the edge of the blank, but you can barely see it in the photo. Then I let loose with a 1" paring chisel, followed by one of those combination rasps that has one flat and one half-round each of  coarse and fine teeth. I'll put a picture of it in the tools section when I get around to it, but I know many people will know which tool I mean. 

After the rasp it's all the different grits of sandpaper that I possess, followed by buffing with a little cotton wheel on my Dremel tool. I don't recommend this method of buffing, as it is too easy to slip the little wheel off the surface of the bridge and hit it with the spinning collet. Good thing the ebony's so hard. Here with the appropriate chapter and verse of  the "Bible" for a background, is the finished bridge.

I read this clever tip somewhere about using a razor blade with the corners broken off and a burr burnished onto it to make a mini-scraper for removing the finish under where the bridge will go. Don't believe it. I burnished and burnished and couldn't get a decent hook on this thing. In addition to that, a French polish finish is so thin that all you need is a little hundred grit to get rid of it with much less damage to the underlying wood than you get by scraping. Lesson learned. 

The bridge clamped down in the usual way. How I got to this point is a comedy of errors. I made some cauls by gluing cork to the bottom of some small blocks of wood. I figured I didn't really need to wait as the tack of the not-yet-dried glue would hold the cork in place. I did a trial run of the clamping and all went smoothly, but when I took it apart to add the glue and do it for real, the cauls were clued to the bridge by glue that had squeezed through the cork. Because the bridge had been finished with its own resins as it were by simply buffing, there was nothing to keep this glue out of the pores of the bridge. A long bout with sandpaper and rebuffing intervened. I finally glued the thing down, as you see in this photo, without cauls but with pieces of cork directly under the clamps. 

I didn't, this time, take photos of the process of making the nut and saddle, because it was so small and fussy and because my impatience to hear this guitar overcame my dedication to documentation just this once. These photos aren't quite the end of the process. I had used MicroMesh abrasives to polish the French polish, as it were. Coming in grits from 1,500 to 12,000, they claimed to be able to put a high gloss on finished wood. 

 I was disappointed in the finish. Blotchy and with not much of a sheen, most of the body was not very attractive. I know that MicroMesh can do the job, though, because the peghead came out quite nicely -- except that the finish wore through at the edges. I'm trying to analyze the reasons for the difference. It's possible the peghead was flatter and I know I did a better job of filling the pores there -- something I will pay much more attention to next time. I'm reading around in hopes of clues.

I was having trouble finding the last two items I needed, according to the sources I used: a 3-M product called "Perfect It" and Meguiar's #7 Show Car Glaze. Both are Auto Parts Store items, and as it turns out, both are pretty easy to find once you've found an auto parts store. Astonishingly to me, I couldn't find such a store by simply driving down Route 1. Not being much of a gearhead, I don't spend a lot of time fussing with my car, and I haven't been to an auto-parts store since I moved to this town eight or so years ago. I had a vague impression that they were just everywhere. I knew of two that were located in places where parking was a nightmare, so I hoped to find one that was more in my usual route of weekly chores. Due to my commute, finding one during the week was out, and for a while, the weekends were full of social commitments. 

To make a long story short, I found Meguiar's on the web and used their dealer locator to find a dealer located somewhat nearby and this weekend (July 29; the guitar has been strung up for a week) found the two items I needed early on Saturday morning. Using them to polish the polished polish took about 45 minutes and made an incredible difference. There are still flaws in the finish that will be lessons for next time, but now it shines like...a new guitar. 
Also after these pictures were made, I spent time making adjustments, chasing buzzes in the nut and the saddle, and compensating the saddle with different compensations for each string -- you've seen the crooked saddles where the E string takeoff  is at the front  of the saddle and the B string is back toward the pegs and the G further forward, with the rest more or less evenly marching back again toward the pegs. It made a detectable difference in intonation. I discovered that the approximately .15 inches that I added to the scale length to get the rough compensation wasn't quite enough. At the rearmost edge of the 1/8" saddle, the low E string is not quite far enough away. 

When I first strung it up, I let go some of the tension in the truss rod to give the neck some relief by letting it bend toward the pull of the strings. This relief gives the fretboard a curve between the nut and the 14th fret that allows the strings room to vibrate. After a week now the curve is getting more pronounced, so I will put a little tension back into the rod. A few of the frets are showing a tendency to catch my fingers, so I'll need to re-dress their ends. Many different small adjustments to make, but overall the guitar is easy to play and has a rich, full sound. The bridge, I think, is too thick at 3/8" -- there's very little saddle under the two E strings -- so I might have to take it down a bit. However, this is the most humid time of the year, and the top tends to crown up with humidity, so I'm going to wait and see what happens in the fall and winter. I may need to make a winter saddle when the strings come down too close to the frets. A problem with the low saddle as it is now is that the angle the strings make going over the saddle is so small that the pressure on the saddle is lessened, which lessens the amount of volume and attack. A too-tall saddle (relative to the top of the bridge) risks tipping forward under excessive string pressure.

 

Updated July 29.

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Copyright 2001 Stephen Miklos