The deck rises and falls

Trying to restore a semi acoustic guitar.

The instrument has been exposed to water, which has made the deck weak and saggy.

 

The electronics are not faring much better.

Sealing all the holes before injecting ammonia

 

Injecting the ammonia and slowly raising the deck over the course of 24 hours,

The structure of the load bearing parts of the deck were unfortunately too weak, and as soon as pressure from the strings was applied, the deck sank again :-(

Too bad, the sound was awesome while it lasted.

Building of a guitar Part 20 – Testing the instrument

There were a couple of issues that I hadn’t taken into account when I bought the bridge and tail piece. Both were intended for a Les Paul type of guitar with a fret board radius that is significantly smaller than that of a Jackson fret board, which is more of a shredding fret board, that meant that then D and G strings were a bit too high for comfort. The bridge follows this curvature.

In order to compensate for this the slots in the bridge were deepened to about the same level.

This unfortunately didn’t cut it, as the E strings wouldn’t get enough down force across the bridge, and therefore would cause an awful buzzing sound. The strings were still very high off the fret board, and I had problems getting the strings intonated right. There were two factors I hadn’t taken into account, when I measured and tested the position of the bridge. The bridge was placed directly under the strings.

But I forgot to add the height of the bridge posts. That meant that with the bridge posts the strings were too high, and every time the string would be pressed to the fret board, it would go sharp. The sliders on the bridge couldn’t compensate for this, and filing several millimeters off the bridge didn’t help either.

Considering the problems with both the tailpiece and the bridge I decided to scratch both of them, make a new tailpiece and buying a new bridge with a higher radius and a longer slide path.

Building of a guitar Part 19 – Its all in the paintjob

It took three attempts to get the paint job halfway decent (and 10 seconds to ruin it again, more on this later). My two first attempt at painting the body was using paint from a spray can. The finish looked decent.

The paint did not run particularly and settled in a somewhat glossy finish, which I then sanded down to grit 2000, and buffed it out (sorry no pictures). The only problem was, that when I restrung the guitar the treble was ruined. The semi-rubber like consistency of the paint job, completely absorbed all the crisp notes, that I had experienced previously. This could only mean one thing… the paint had to go -> Yes indeed more sanding.

This time I used a sander in order to get a more even surface.. and because I wanted to speed things up. There were some minute dips in the cellulose lacquer where I couldn’t get the paint job off, without going through the cellulose lacquer layer, so I left it on the guitar as a filler.

After the sanding the guitar looked like this.

 

When I had put the electronics in the first time, there was a significant humm from the amp, that was caused by the guitar not having sufficient shielding, so I got a hold of some shielding foil. and filled the pickup cavities and the control pocket, making sure to connect each pocket with a common ground wire.

Then it was off to the basement to paint the sucker.

For this I went all out, and bought myself a compressor (every man should have one) and a spray gun. these were necessary as I intended to use car paint for the finish, as I wanted the paint to e as crisp as possible in order to avoid the loss of the higher nuances of the tones I experienced previously.

The guitar got two coats of paint with a bit of sanding in between, then it looked like this.

Unfortunately I didn’t buy a water separator for the compressor so water droplets would cause small dimples in the paint job, that needed to be covered. I managed to drop the body during one of these covering sessions and therefore it has a scar on the left side, and couple on the side facing to the right (I could kick myself!).

Since it would take quite a bit of work to solve this issue, I decided to proceed to testing the guitar as an instrument.

Building of a guitar Part 18 – Its like the Sahara desert!

The sand(ing) never ends!

Started applying the first layers of lacquer. But first a bit of sanding, in order to have a level surface. The difference of hardness of the grain and the rest of the wood really shows here. The grain lying parallel with the surface was practically impossible to get level, as the softer wood along would be sanded away, before an significant impact on the harder grain was made. I therefore decided to stop sanding, and give the surface a coat of lacquer, in order to harden the softer parts of the wood. Here yo can see the difference the lacquer makes.

The problem with the parallel grain is especially noticeable in the upper left middle part of the body. This is luckily the back part of the guitar. The front looked like this after the lacquer was applied. Notice how the grain is almost luminous, when exposed to the flash.

After the lacquer hardened the body needed… a bit of sanding, in order to level the grain. I started out with grit 40 sanding paper, but didn’t really make an impact

I soon lost my patience and started using a power sander, with paper grit of about 80-100 I would think. The result looks like this.

Almost all of the lacquer was removed, but the surface was left smooth, with significantly lower grain parts.

The edges that I thought to be fairly round turned out to have some slight edges, which showed, when using a piece of sanding paper, like a shoe shiner shines a shoe. The sanding paper would only attack the parts of the wood “sticking out from the circle, thereby making the corner more evenly round.

Building of a guitar Part 17 – Putting a lid on things

Next the grove for the cavity cover should be routed. Using the original cavity stencil with an offset, the pointy part of the grove was created first. The widest par of the grove was made using a straight piece of wood as a guide.

This was necessary because the stencil would cover the widest part of the cavity when being offset. The area between the two routing tracks was handled using a Stanley knife.

The cover itself was made from a 2.5 mm sheet of aluminum. My initial thoughts were to make the lid out of a 2.5 mm sheet of steel, but experiences from creating the neck bolt plate had shown the hassle it is to shape steel. So aluminum it was.

The piece was cut out in roughly the shape needed, and with a combination of grinding and sanding fitted to the cavity groove. The fit is actually so good that when I managed to get the plate into the grove, I had a hard time getting it out again :-).

The lid looks like this:

Building of a guitar Part 16 – The limits of control

All the holes in the control cavity needed to be created next. The hole for the jack socket was drilled first:

The area around the hole was then carved in order to fit the jack socket plate using files and in the end a dremel (the filing took for ever). I wanted the cable to com straight out of the back of the guitar, so I’d chosen a plate of this type:

I of course went for the black one :-)

Then the holes for the pot controls like volume ton and mix needed to be drilled. They were drilled using a 2 mm pilot drill, from the bottom up, in order to make sure the holes would align correctly with the cavity. Then the real holes were drilled using a 6mm drill from the top down, in order not to create visible scars on the wood as the drill exits the wood.

The cavity side, notice the nasty splinters around the exit hole. This is why one should always drill from the visible face.

Then the slit for the pickup selector switch needed to be created. I considered several options, like roting using a drill instead of a routing bit, simply cutting it using a Stanley knife, but ended up using a dremel and a cutting disk. This operation would be don free hand (hands sweaty of fear).

The slit ended up being a bit thicker than I would have liked, but overall I’m quite pleased with the result.

It turned out that even with the little stunt I did when routing the controls cavity, the top was still too thick. The top has therefore made thinner by 1.5-2mm around the slit using a fine wood chisel. Luckily the wood is very soft, so it took no time.

The wood being this soft makes me worry about the structural strength of the top. I hope that gracious amounts of lacquer will strengthen the cavity top, so that it wont break over the years.

Building of a guitar Part 15 – Connecting the slots

Next was drilling the holes for the pickup wires. The holes between the pickups were easily drilled using a standard 6 mm drill, but in order to be able to reach the controls cavity, a different kind of drill would be needed. Making sure the drill would actually miss the bridge socket and reach the cavity:

I was terrified that I would miss the cavity and have the drill go out the bottom of the body, but my fears were not justified. The drilling went smooth, and hit the cavity in just the right spot.

Building of a guitar Part 13 – Making room for control

The guitar needs a cavity for the electric controls. Using my Ibanez as a guide, I decided to place all the controls in one pocket, in the lower part of the body. Since I plan to have all three coil based pickups along with a piezo based pickup, the control room should be fairly large, in order to have room for all the controls. I pondered different shapes for the controls cavity, but finally decided to go with a standard right angle triangular shape, that would take up most of the lower “fin” of the body, without jeopardizing sing the structural integrity of the body.

The keen eye will notice that once again the router got the best of me. This time because i started moving the router out of the hole before it had come to a complete halt. Luckily a the mistake will be covered by… a cover.

The top of the controls cavity should be fairly thin in order to have the controls be able to poke out through holes to the surface of the guitar. It turned out that the router wouldn’t be able to carve that deep using the stencil, as it added 12 mm the height. This problem was discussed a bit with Tobias but no immediate solutions arose. Until it hit me, why not use the edge of the cavity as a stencil to reach the bottom. This would of course make the hole a bit more narrow on the bottom, but it should be fine. It turned out that using the edge wasn’t enough, I was 2 mm short so to speak, more drastic measures were needed.

I noticed that the router had a plate at the bottom, in order to give it a smooth surface… lo an behold it was exactly 2 mm thick.

Setting the routing in its most extended position (and praying it wouldn’t fly off and maim me), I started routing to the bottom.

The removal of the smooth surface, caused the router to rough up the surface of the body quite badly, but nothing a bit of sanding won’t be able to fix.

The cavity after the two step routing:

Building of a guitar Part 12 – Bridge it Jones diary

Having made all the measurements it was now time to insert the bridge in the body. The bridge was offset by 1 mm in order to compensate for the misaligned neck. It should be possible to compensate for the rest by forcing the neck a bit, when gluing it to the body.

The rough measurements with the “floating” bridge were used to marked the place where the bridge should be placed:

I wanted to have a good connection between the bridge and the body, and in order to achieve this, the holes for the bridge “sockets” were deliberately made smaller than the sockets themselves. This in tern meant that the sockets needed to be sharpened in order to be able to drive them into the holes.

Using the actual bridge as a distance measurer the second bridge stud was used to mark the placement of the other hole, by driving the stud into the body with a hammer.

Unfortunately it turned out that the wood was too soft, and the stud penetrated to deeply, thereby allowing the bridge to leave a significant indentation in the body:

It should be possible with a combination of water exposure and sanding, to reduce the difference in height. If everything else fails, the lacquer needs to be a bit thicker in this area. Notice the beveled edge of the hole, in order to have the socket be completely level with the surface of the guitar.

Building of a guitar Part 11 – An instrument emerges

In order to have an idea of how the guitar would sound, the bridge was placed on the body, using two coins as standoffs. The string tension held the bridge in place, while still making it possible to move it back and forth.

This would also give an estimate of where to place the bridge, in order to have the correct intonation. Placing the bridge in the wrong position, converts a promising guitar into a unplayable decorative object, as it will be unable to play in tune.

The bridge placed on the body:

It is funny how all of a sudden, the pieces of wood and metal come together and form an instrument. The body transmits a LOT of sound, and would be able to be played as an acoustic guitar around the more quiet camp fires…. if one believes in that sort of thing :-). In order to make an rough estimate of the intonation, a piezo was placed under the bridge and kooked up to an amplifier and tuner. Thereby making sure that only minor adjustments are needed, once the bridge is embedded in the body.

I didn’t shoot any pictures of the neck attachment process, but the result can be seen here:

The plate is 2.5 mm steel and the screws are special screws with deep grooves, for extra grip in the neck. The neck holes were deliberately drilled 1 mm thinner, in order to have the screws have maximum grip. This could potentially have had dire consequences, as the wood could have split under the tension. Better grip was deemed all important though, as the lack of good grip can be observed in the form of mangled screw hole on the left. I am considering filing/sanding the neck in order to have the shape fit the guitar better.

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