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Once finished, I guess the excitement is over… The guitar has been essentially done for about a month now, and I’ve never gotten around to posting about it!
We left off last time having sprayed the clear coat on the body, which left only sanding, polishing, assembly and setup. And I’m afraid at this point I stopped taking pictures of every step, but here’s what we have.
Sanding and polishing! This admittedly could have gone better, but what are you going to do? Here, the clear coat has been left to harden for a couple of days, after which it is hard enough to take sandpaper to without scraping it all off. Or so I hoped. Why sand in the first place? Well, when sprayed on, clear coat tends to develop an ‘orange peel’ surface, due to surface tension or whatever just makes this happen. Zoom in close to the pre-sanded body to see:
Lightly sanding the body should remove the high spots and generally flatten the surface. Polishing will further hopefully make it glass-like. So, we sand, starting with 400 grit sandpaper, working up to 2000 grit.
I use a wet-sanding technique, lightly spraying the body and rinsing the paper, otherwise the paper can gum up and cause scrapes.
This all should have gone swimmingly, but I ran into issues with the body not being perfectly flat. Recall that the front and rear face of the body is cheap pressboard. Well, it turns out that any place that I exposed an edge by cutting or drilling into it, that edge could absorb moisture and expand a bit. Below is an extreme example; this is a hole that the grounding wire for the bridge (the thing that holds the strings to the body) is run through. What happened (I suspect) is that the primer paint soaked in and caused the raised area.
This was the worst spot on the guitar by far, and luckily gets hidden under the bridge once installed. Similarly, there was bubbling under the neck plate on the back, at the pickup adjustment holes on the back, and at a couple placed where the binding met the body. I started sanding the back first and just went at it assuming everything was perfectly flat, so my sanding block ended up going through through the clear coat and paint there. Waaaahhh!!!
That’s all on the back, which will eventually get all scraped up from belt buckles (assuming I actually play thing regularly), so it’s not the end of the world. I still have a bit of the green paint left too, so I’ll touch it up eventually.
That said, this left me scared when sanding the front, so I wasn’t anywhere as aggressive, switched from a hard flat sanding block to a rubber block as seen in the picture above, which meant that although I managed to avoid sanding through the paint, I also didn’t completely rid the front of the orange peel. But on the plus side, having seen a couple vintage 1960’s Danelectro guitars, it looks like my imperfect finish looks kinda like an aged copy!
OK, after that, unfortunately not many pictures. I bolted the neck back on, installed the bridge and pickguard/electronics, strap buttons and output jack. That makes it a complete guitar!
But assembled doesn’t mean playable. The final task is called “setting up” the guitar, which is a series of adjustments made to make sure the guitar plays easily and in tune. This involves a few things, all of which affect the others, so setting up is an iterative process. Item:
- Intonation
- Neck Relief
- Action
- Nut Height
- Curvature
- Pickup Height
Why so many factors? OK: let’s pretend the guitar has a single string, for simplicity. You pick the string, it vibrates and makes a sound. The frets are on the neck so that you can shorten the string by pressing down at a fret. A shorter string vibrates faster, so you get a higher note. Again simplifying things, we’ll ignore all of the frets other than the twelfth one. When fretted, this gives you the note one octave higher than the string played ‘open’. And length-wise, the twelfth fret length is exactly half of the open string length. Or more precisely, *should* be half the length. The bridge, where the strings are held at the body, has ‘saddles’ that the strings ride on; these saddles can be adjusted back and forth to make sure that the open string length is exactly double that of the twelfth fret length. This adjustment is called intonation. And for pendants out there, yes, this distance isn’t actually double the twelfth fret length; the physics of how the string starts vibrating at the saddle means that each string thickness reacts a little differently. That’s why when you look at a guitar’s saddles you see they are staggered slightly; the fatter strings tend to be intonated a little ‘long’. Also, it’s almost impossible to intonate a guitar perfectly across the entire fretboard, so you need to adjust the intonation by ear for where you typically play, i.e. open strumming near the nut, or soloing meedly meedly style way up the neck.
Next, in no particular order, action. This is basically string height as adjusted at the saddles. The saddles not only can be adjusted back and forth, but up and down. Ideally, you want the strings as low as you can get them. Why? Again, let’s simplify and consider the twelfth fret. For a perfectly intonated guitar, when you fret here, you are halving the string length, hence making the string vibrate twice as fast, resulting in a note an octave higher. But you aren’t just halving the string length. By pushing the string down on the fret, you are also stretching it slightly. This added tension also affects the string vibration, increasing it a bit, and making tte fretted note slightly sharp. That’s a bad thing. So by adjusting the string height as low as possible, this stretching is minimized, making the fretted note close to perfect. Adjusting the intonation can make this even better, but at the cost of making the open strings a little less perfectly tuned. Sigh. And on top of that, you can only go so low with the string height, because the vibrating string will eventually hit the other frets. If you play loud, then you won’t be able to lower your action as much as if you play soft. It’s another trade-off.
But next is neck relief, which helps in a couple ways. First is the massage that my sweetie gives me after leaning over a guitar setup all day. Now that’s neck relief! But on the guitar, this is an adjustment of the bend in the neck. Remember when we build the neck, we wanted it to be as straight and flat as possible? Well now that we have strung up the guitar, the neck has been pulled like a bow:
This is actually a good thing, as it gives the strings a bit of room to vibrate, so you can lower the action more than you could if the neck was perfectly flat. There’s a balance between string height and neck relief, luckily we also have guidelines for recommended relief settings to start with. Neck relief is adjusted using the truss rod – this, when tightened, pulls the neck back against the string tension to flatten the neck.
The nut height controls the string height at the headstock end of the neck, kinda like the saddle adjustments at the saddle. The differences here are that the adjustments are permanent, being done by filing slots into the nut to the correct depth. How high should the bottom of the nut slot be? Well at the very least, it should be as high as the height of the first fret. This would mean that the nut would kinda be like another fret being held down (fretted). In fact, there are guitars that use exactly this, a ‘zero fret’ instead of a nut. Like my first Telecaster!
Here, the white plastic that looks like a nut doesn’t actually support the strings; it’s just there to hold them in place side-to-side. The ‘zeroeth’ fret is where a traditional nut would be placed.
But I digress. The Covid guitar has no zero fret, it has a unique aluminum (!) nut. Most guitars have plastic, nylon, or, for bonifide guitars, bone nuts (Really. Made of bone). The Danelectro’s were cheap though, and used hunks of aluminum. This was just another thing that gives them their twangy sound though. It makes filing them a little more work than bone or plastic, I must admit. And as you need a special set of files for nuts (each slot has to match the guitar string diameter…), I hope that my files aren’t ruined by the aluminum!
The angle of the slot should also point as close as possible to where the string winds onto the tuner, in order to minimize friction when tuning the strings.
As mentioned above, the slot can’t go lower than the next fret; in order to minimize string buzzing on the first fret we want it just a little higher. Not too high, though, or we’ll get sharp notes when fretting near the nut (due to string stretch). So what we do is fret between the second and third frets, and measure how high the string is above the first fret:
About 0.01-0.015″ is acceptable.
Next is curvature. This refers to the arc that the string heights are set to above the frets. You want each string to have the same height above the fret, and since each string has a different radius, you have to measure from the bottom of the string. A fancy little tool comes in handy here. I know that the fret radius is 12″ (because that’s how I made it), so the tool below has a matching 12″ radius on its top. When I did the other setups (string height, action, etc.), I did that only for the top and bottom strings, not the four in the middle. Knowing that those two are correct, I can adjust the middle strings using this tool to ensure the string height follow the right curvature.
With all that stuff done, all that’s left is the pickup height. Each pickup can be adjusted using the screws that come through the back of the guitar. The distance from the pickup to the strings should be close enough for strong transfer of the string vibration to the magnetic coils (the closer, the louder the guitar can be), but too close and the magnets of the pickups will actually ‘grab’ at the strings and affect the tone and sustain of the sound. Looking at the above picture, the pickups are already adjusted, and they may look really close to the strings, especially if you are used to typical single coil or humbucker pickups, but the lipstick pickups are by nature a little weak, so they have to be closer. Also, the lipstick tube itself is not part of the magnet, so the magnet isn’t quite as close as it appears.
And that’s it! Braggy photos next!
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