Mopus chapter 1 : The story so far…

At this point, I can say that Mopus is underway. For a while there, the project was stuck in a murky swamp called “just one more thing before I really start”. There was some major prep work to be done first, the most significant was the purchase and setup of a bandsaw. That alone took a few weekends before it was ready to go, outfitting it with a moble base and a riser block, and fiddling with various blade setups. Still more to do there – no dust collection yet, and I need to rig up  some better fence options.   

Then there was the whole hide glue extravaganza. I’ve decided to use hide glue on Mopus for various reasons – bottom line being it really is the perfect glue. It’s super easy to clean, it’s reverseable if a repair is necessary, it’s natural and non-toxic, and it sets so fast that clamps are often not needed. However – and this is a big however – it needs to be heated to a very precise temperature and kept at that temperature. Even a 5 degree difference matters, so you can’t just wing it. I eventually rigged up a temperature controlled water bath for this purpose. I’ve also prepared enough glue for Mopus, and have made frozen glue ice cubes for quick use. Hide glue has a short shelf life if not refrigerated or frozen.  

  

I also mixed batches of shellac by using ground dewaxed flakes mixed with Everclear, but I’ve done all this before so at this point it’s no biggie. But I did use nicer bottles this time. I made 2 pound cuts of various tints, and will dilute to 1 pound or less when I get to the French polishing stage.

 

The true start of Mopus was when I started working on the guitar mold. The mold determines the shape of the guitar body, in this case a standard OM. It is important to me that I make the mold myself,  rather than buying one, giving me a lot of flexibility in the future. Besides, as they say, “if you can’t make the mold, you can’t make the guitar”. In the process I did run into issues using a router to trim plywood. I wound up making an impromptu router table, otherwise I could have easily lost some fingers. I need those fingers.

  
Here’s what the mold looks like so far, a little more to go before it’s ready for action.

        

Finally it’s time to work on some real wood! The first step is to prep the rosewood sides. These come as a book-matched set, but they are way too thick to use as is. Making them a uniform ~0.1″ thickness poses some real challenges (unless you have a thickness sander, which I don’t). I did some rough thicknessing with a Safe-T-Planer and a jig I made for this purpose almost 2 years ago. At the time I thought I was preparing to make another acoustic, but then wound up taking a 3 electric guitar detour. And now two years later, my Safe-T-Planer setup is finally being taking out for a spin. 

  

After rough thicknessing, quality time was spent with scrapers. This takes a great deal of effort, and I still have more to go. And after this, I have to do the same thing (only more so) for the back. It does help to have good and correctly sharpened scrapers,  and I’m getting better prepping and using them. So I do have some hope.

 

I tried out a new random orbit sander to do some additional smoothing.  I love this thing! I should have gotten one of these long ago.

 That’s where things stand today. I’m getting very close to bending the sides and starting the rim.  I may even get to some of that this weekend. 

Stay tuned to see a guitar take form out of (almost) thin air!

The Mopus Project

It sure took Spring long enough to get here, but now that it has….

Time for a new project. This time, I’m going to build an acoustic orchestra model (OM) guitar, pretty much from scratch. My first acoustic was built from a Stew-Mac kit, and although it was very challenging some of the tricker parts came already done. For example the sides were bent, the rosette channel was already routed, the back and front plates were thicknessed and joined, the sound hole was cut, the fretboard was radiused and slotted, and the neck was rough formed. Boy, saying it like that I wonder why I was even challenged. Actually, it was plenty overwhelming at the time, but now that I’ve built 4 guitars and they all work, I guess I’m getting cocky.

I’m calling this the Mopus project. I needed a name other than “guitar build #4”. I see this project more about setting myself up to be able to build any guitar rather than one specific guitar. It’s not even completly about building guitars, but that’s my main goal. I was recently reminded of a kitten named Mopus I once had long ago, and the name stuck in my head. It’s a pretty random name for a project, and I like random, at least for project names.

I will not only be building a guitar, but also many of the tools, forms, and jigs required. This should not only save a boatload of money (which is critical to me doing anything these days), but also be more flexible and ultimately more useful. That said, I will need to tool up in a few well chosen areas. Maybe the most significant is that I’m finally getting a bandsaw. I bought a 14″ Grizzly, and it’s already been shipped.  To me, that’s like graduating to the next level! It’s amazing how much I did with that toy Black & Decker, but calling it a toy is just being kind.

Other prerequisites are in motion. The guitar wood and hardware is on its way. All my chisels are very sharp. A while ago I bought some old (~100 years) Stanley planes on eBay, and they are now all ready to rock. I’ve made many adjustments to the microshop and there’s now more of an actual shop. And theres a whole guitar side bending story to tell later. If it looks like a project, and smells like a project, it must be Mopus.

So to close this first post of the Mopus project, here is my inital attempt at a homemade thickness caliper. I will have to modify it, because the body has too much flex, but it sure looks cool so far :) Maybe I’ll write about it when it actually works as planned.

Feature Tour of build #2

Here’s a quick tour of the features of the guitar I just built.

One piece swamp ash body

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It would be more common to use a alder or several pieces of swamp ash joined together. Because I wanted the body to be completely natural, I used a single piece of swamp ash.

Custom asymmetrical body shape

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With a standard Strat template as a starting point, I kept modifying it – making templates for each design – until I liked what I saw. I was drawn to a bit of asymmetry, and also to less pronounced “horns” than would be found on a typical Strat.

Compound Radius Maple Neck

I bought a replacement Strat neck from Stew Mac (it’s actually made by Mighty Mite). The model I have has a compound radius and a maple fingerboard. I started out thinking I’d make the neck, but using a pre-built one saved me a ton of time. I was kind of in a rush to use this guitar for my lessons.

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Customized headstock with mother-of-peal inlay

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I couldn’t use a neck without doing something to it. So I modified the shape, created some contrast with a layer of rosewood, and installed an inlay of my logo at the top using mother-of-pearl.

Roller Bridge

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I originally wanted to do a string-through-the-body type bridge, and I had visions of adding piezo ghost saddles to it. But that idea was derailed when I discovered that my drill press is not large enough to reach where the holes needed to go. I went with a great backup choice – the Schaller Non-Tremolo Roller Bridge. This bridge has excellent adjustments, you can move the string positions up and down, and also side to side. It looks cool too.

Locking Tuners

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I looked at several tuner choices before settling on the Gotoh Mini-510 Locking Tuners. These are similar to the tuners I put in the acoustic, but smaller. They also have a cool locking feature – you do not wind the strings around the posts, instead you just put the string through the hole and turn the knob. The strings are then automatically clamped into place. The color is “cosmo” which is a black finish over chrome – a look that has some interesting depth to it.

String Tree

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Nothing too exciting here – it’s just a nice way of managing the longer string runs on the headstock. Most electrics have these.

Offset Strap Button design

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This one is a result of the asymmetric body design. As soon as I cut out the body, I realized it would fall over easily when leaning against a wall. Then it hit me – simply position the bottom strap button in a spot that would cause the bottom to be level. It works great and I like it a lot! In keeping with the whole asymmetry thing, I put the top strap button off to the side too.

Dimarzio Area Pickups

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After much research, I went with a set of Area pickups by Dimarzio. They are a very low noise design – sort of a humbucker disguised as a single coil – but a much better design than most other attempts at low noise singles. I’m actually using three different model pickups – an Area 58 in the neck,  an Area 67 in the middle, and a Area 61 in the bridge. After playing around with them, I can say they are more than low noise, they are completely noiseless.

Copper lined control cavities

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I wanted this guitar to be quiet – no buzzing or hums whatsoever. So I grounded and shielded this sucker to death. I used copper tape from Stew Mac – which has conductive adhesive to eliminate soldering each of the pieces to each other,.

Custom Electronics

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You can read all about my electronics saga in this post.

Wooden control knobs

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I found these cool knobs on Amazon after seeing similar ones for more money elsewhere. The maple ones are for volume (in this rev I had two volume controls, now I’m back to one), and the cocobolo ones are for tone.

How many ways can you wire a guitar?

How many ways can you wire a guitar? The answer is more ways than you can possibly imagine. Electric guitars usually have multiple pickups – and each one can have one or two coils. Throw in a few knobs, a bunch of switches – and try to come up with the best way to get the most amount of sounds, a useful volume control (or controls), useful tone control (or controls) – all while making it intuitive to use.

My guitar is essentially a Strat with three single coil pickups. The standard strat wiring gives you the ability to select most (but not all) pickup combinations (in parallel only), with a single volume and two tone controls which only act on the neck and middle pickups.  There are a few “typical” mods made to this standard arrangement, plus an endless amount of more obscure mods.

When I made the pickguard, I drilled an extra hole for a toggle switch, even though I wasn’t sure what to use it for at the time. I also put in a push-pull pot in for the volume control, which is another DTDP switch at my disposal. When I first put the guitar together, I just wanted to try it without frills, so I simply went with the standard wiring. The toggle switches did nothing. Everything worked as expected in rev 1, so then I was free to try other ideas.

One thing I did right away to make it easier to disconnect the pickguard assembly was to add screw terminals to connect/disconnect the jack.

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The first obvious wiring mod was to get the missing pickup combination left out of the standard – i.e. Neck + Bridge. Easiest way to do this is the “David Gilmore mod” – use a toggle to switch on the neck pickup regardless of the position of the 5-way switch. I first did that by using the volume push – pull, but I’ll be moving that function to the extra toggle in my next rev. That was rev 2.

Next I tried something pretty wild. I rewired things to have two independent volume controls (one for neck + middle, one for bridge), a tone circuit with the ability to bypass it or choose between two capacitor values, plus the ability to add the neck and control it with the second volume.  It sounded great on paper, and it actually worked very well (after I finally got it to work), however, my feeling is that it’s too complicated to use. In particular, when you want the volume down, it’s great to have a single knob to deal with. But I did like the switchable capacitance on the tone, so I’ll keep that idea going forward. So much for rev 3, I’m going back in.

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For rev 4, here’s what I’m doing:

  • A single master 500K ohm volume control with push pull. When the knob is pushed in, the switch will add a 500K parallel resistor to make the tone warmer – whereas pulling the knob out will remove the resistor creating a brighter tone.
  • The extra toggle will be a simple SPST to add in the neck pickup regardless of the other switches.
  • A tone control for the neck and middle pickups.
  • A tone control just for the bridge pickup.

I already know what I’m doing for rev 5, I just don’t have the parts I need so it’ll have to wait a few days. Basically it’s the following improvements to the tone controls in rev 4:

  • A tone control with a push-pull for the neck and bridge. Pulling out the knob will remove all the tone controls from the circuit, removing the load and causing the tone to be much brighter than you could get with any tone controls active.
  • A tone control with a push-pull for the bridge. The bridge tends to be overly bright, so extra tone control seems like a good idea. With the knob in, the control will use 0.047uF for darker tones, whereas pulling it out will switch in 0.22uF for brighter tones.

Here’s what today’s version looks like on paper:

guitar wiring

In case someone is looking at this and scratching their heads over the 5-way switch numbering, I have a Megaswitch type S, not the standard 5-way.

I’ll let you know what I think when I get to play rev 5.

 

#2 is Finished! Let the tinkering begin…

I’m now the proud owner of a custom built electric – and it came out pretty damn well if I do say so myself. I still have some tinkering to do with the electronics (which is actually tinker heaven), but the guitar is very usable, it plays great and is nice looking besides.  I’m very happy!

I had a three day weekend, so I had no need or desire to rush. So I really took my time doing the internal shielding – lining the cavities with copper foil backed with conductive adhesive. I also decided to seriously ground the bridge – so I removed it and put a bed of copper foil under it. I even when the extra mile and grounded every single screw. In the end I got something that looked like it could have been built by NASA for a manned mission to Mars.

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I also grounded the entire back of the pickguard. I even shielded the hole the the jack wires go through by using heat shrink tubing wrapped with copper foil. This baby is GROUNDED.

All this work really paid off – because there is NO noise at all when you plug the guitar into an amp – it’s as quiet as a dead mouse.

Next I put in the tuners – hardest part here is lining them all up and then drilling the screw holes. At one time this would have been major drama – not so much anymore.

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And then it was time for the electronics. I’m not going to say much about this, because it’s an interesting topic all on it’s own, and I’m already on rev 3 and going on rev 4 of my wiring design. I’ll get back to that in another post. But here’s some scenes from doing rev 1:

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I then closed it all up, put on some strings, plugged it in and ………. NOTHING. No sound whatsoever. Yikes, what the hell did I do wrong? I resigned myself to taking it all apart and check the wiring, but in pulling out the jack a little, suddenly – sound. Turns out that the jack tip was hitting the shielding in the jack cavity – shorting it out. Some electrical tape for insulation and I was in business.

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So it’s done – but as I said, it’s not the end of the story on this build.  But one thing I can say for sure – this build was WAY fun. Maybe even more so than building the acoustic, but maybe not – I’m not sure, it was so different. It came together quite fast – using an already made neck sure shortened the time quite a bit, plus it’s nice to have all the necessary tools right there when you need them. What a great hobby. And Candi – if you’re reading this – I CAN’T THANK YOU ENOUGH for getting me going in this obsession!

Another Penultimate Day of Guitar Building

Today was a big day in guitar building land. But first a bit of bringing the story up to date…

Since the last update, I attached the neck and bridge to the body. Although the neck had nicely set frets already, the edges needed to be dressed to be nice and sooth. So I got to use my homemade “super flat sanding stick”  which still had sandpaper on it from the acoustic build. I also rounded off the fret edges with a fret file.

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I spend some time sanding and applying shellac to the neck till it looked like it was done. To attach the neck, some carefully measured holes had to be drilled, and I measured everything to death to be sure I got it right.

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Once the neck was in place, the neck could be positioned. As obsessive I was about getting the measurements right with the neck, I was more so with the bridge.  After much double and triple checking, I drilled the  holes and screwed that sucker in.

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And that brings us to today.  I spent almost the entire day working on the guitar, and all that time went into working on a component that was easily the most difficult part of this project.

If I was building a garden variety Strat, I could have bought a nice already made pickguard. Many choices out there for Strat pick guards, but here’s the thing – my guitar shape is unique. A unique guitar requires a custom made pickguard, and that’s what I did today. It came out fine, but this was far from a no brainer for me.

I had bought a sheet of laminated pickguard material a while back from China via eBay. I had it in my head that I wanted the pickguard color to match the wood somewhat, and I couldn’t find anything that I liked from the usual vendors. I got a sheet big enough to make two pickguards, and that turned out to be a good thing, as you shall see.

I spent most of the time making a template, because I was going to use a router and various bearing bits to do the shaping. I started with a standard Strat design, and then modified it to suit my guitar’s contours.

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I glued the cardboard to a piece of MDF and cut out the template. I spent quite a bit of time sanding the edges to make them nice and smooth.

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I then double stickied the pickguard material to the template and cut it with the bandsaw. I was expecting a possible problem with the material heating and maybe melting, but that really didn’t seem to be an issue.

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I then used the Bosch Colt laminate trimmer with a flush cut bit to trim the excess. It worked very well, but made a really interesting mess.

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I was pretty pleased with myself at this point, this is what the pickguard looked like. Next it was time to make the cutouts for the pickups.

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Once again, I put quality time in making a template. I had a brainstorm – I figured I could use the pickguard of my old Duo-Sonic II – which also had single coil pickups – as a template to make the template. It turned out that the pickups were slightly smaller than normal, but it still helped to make to make the master template.

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Then i used the master template to cut out my pickguard template, and it was time to cut the holes. I new one mistake would spell disaster, since the holes have to fit the pickups exactly, any error would be very visible. All went fine for the first two holes, but on the third and last one, DISASTER STRUCK! The router jumped because it hit on a sharp edge, and completely ruined the rout. I was so BUMMED!

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Thankfully I still had half of the pickguard material left. In a situation like this, it’s best to just jump right back in.  I already had the templates, which after all was the most time consuming part anyway. So I’ll just skip over describing all the stuff I did AGAIN. This time I was more careful, and there’s no doubt that the second time comes out better anyway. So I suppose it was meant to be.

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There was also some drama with cutting the 5 way switch slot and drilling all the holes, but in the end I got it all done. Oh and there was also the almost disaster when I realized that the plastic wrap I was using to protect the pickguard left a nasty residue, which for awhile I thought I wouldn’t be able to remove. Turned out that Everclear was the perfect solvent, and left absolutely no residue at all. I also countersunk the screw holes and more stuff, but by that time I was on a mission from gad and it was just a blur of activity.

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I tried fitting the pickups and controls into the pickguard, and found that they didn’t quite fit the routed holes in the body. I spent over an hour chiseling away until everything fit. I didn’t really want to finish everything today, but I did want to be sure the controls would be OK, so before I mounted everything I first applied copper shielding to the backside of the pickguard.

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And so I had the final show and tell of the day, a guitar with pickups, switches, knobs, and pretty much all the trimmings. If all goes well, I should be able to finish this thing TOMORROW!. That would make today my second penultimate guitar building day!

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It wasn’t only a rout, but a good shellacking too

We now join our regularly scheduled program already in progress…

I’ve been making good progress on the electric, to the point where I’m starting to really look forward to playing it – and soon! Here’s a recap of what’s been happening in guitar building land.

I’m definitely finding that building an electric guitar is quite a different undertaking than building an acoustic. One major difference is the fact that you actually install electronics in it. Those components need a place to live, and to do that, I broke out the larger router and started making cavities deep in the wood. Power tools – cutting large holes in a guitar – yep, pretty different than an acoustic.

After some internal debate, I decided to go with the control layout of a standard Strat, mainly since I couldn’t really come up with any reason not to.   I made various templates to guide the router bit as I went. Some of the control cavities are quite deep – reaching as far as 1/4 inch from the back side.

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The neck pocket is pretty critical – I wanted to make sure the neck sat at the right depth and at the right angle. I thought about this one for a while – eventually coming up with the jig you can see in the following pictures. There is a small block of wood towards the tail of the guitar with a center line marked on it – aligning the line with a corresponding center line on the guitar guaranteed that the neck would be in alignment. I also made a template to fit the curve at the end of the bolt on neck.

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Initially I was a bit bummed that the fit seemed sloppy, but when I measured it I only had a 0.025″ gap. Gluing a very thin sliver of wood to fill the gap made the neck fit quite snugly.

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I was pretty pleased with the progress, so I was done for the day at point.

When I got back to business, I decided to first contour the body to make it look less like a block of wood and more like a guitar. First I beveled the edges using the Bosch Colt laminate trimmer with a round-over bit. The Colt is a pretty nice tool, usually you’d use a full size router and a router table, but I was able to do this freehand quite easily.

The “tummy cut” and the “arm bevel” are standard features on many Strats, so I figured – why not? Hey, this is my guitar, I can do anything I want, right? I did not follow any templates – instead I just did what made sense to me – using rasps, files, planes, sandpaper, and explosives.  I really like how it came out.

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I was about to start working on applying finish to the guitar when it suddenly occurred to me that my guitar did not have a hole for a jack! Whoops. Back out came the router, and I made a quick template and cut away. One thing I don’t have photos of is making the hole that extends from the jack to the control cavity. This took some thinking – I eventually made a groove in a piece of wood which I double-stick taped to the body to guide my drill bit at the right angle.  Thankfully, that worked, because I was a bit concerned that my drill would come out the back of the guitar.

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Now it was time for a mud bath. Yes, a mud bath. Swamp Ash is an open pore wood, which means it’s a really good idea to fill the pores with something before applying a finish. There are many options for doing this, but I just happened to have some filler left over from making the mahogany neck of the acoustic – so that’s what I used. I’m not really fond of this step – it makes a mess and sanding the mud off makes a lot of dust. But the end result was nice – nice smooth wood with a hint of ruddy color – and much more pronounced grain.

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At that point I was was done for the day. And every inch of my body was covered in dust. Thankfully I used my home-brew triple stage air filter and a good dust mask, or I’d be on a respirator right now.

And that brings us to today. I never debated what finish I’d use on the guitar, shellac / french polish is too perfect a choice for this situation.  However, I did wonder for awhile which tint to use. I have 5 shades of shellac flakes – from light blond to dark garnet. I used several shades on the acoustic, and they were all very nice. But I forgot to mix some last night, and it takes roughly a day to fully dissolve shellac.  By chance, I sill had some amber shellac from a previous project, already mixed to a 0.75 # cut. Hey, now that I think about it – amber would be perfect!

It’s amazing what a few coats of shellac will do, and even more amazing what happens when you get through 4-5 rounds of french polishing. Really it’s a perfect finish, you can sand as you find dings, and the dust from the sanding fills any remaining pores when you apply more shellac.

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Hey this is looking like a real guitar body now! While I had all the finishing junk still out, I figured I should clean up the peghead on the neck a bit. The rosewood is another open pored wood, so I gave it an ebony mud bath.

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I also made a subtle but to me important tweak to the inlay. Using an exacto and a few other sharp objects, I scored around the tip of the angle where the inlay juts into the maple. Into this channel I put some rosewood sawdust and a few drops of CA glue – then a light spray of accelerator. After sanding it down, I got the effect I wanted. I think the contrast makes the inlay pop a bit more. To seal the headstock I used a few coats of shellac, but the actual french polishing will happen another day.

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And voila, something that resembles a nice shiny guitar!

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It is now time to get some components to put in all those holes. I need pickups, a bridge, tuners, controls, a jack, and a partridge in a pear tree. I might start on the pick guard before I get all that stuff, but I really should wait to get some exact measurements. We shall see what happens!