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The Guitar Medic

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Conn F-2712 Acoustic 12-String "Multiple Injuries" - As Received
Phil purchased this F-2712 12-String Conn guitar, and had it mailed directly to me. He asked me to look it over and determine what repairs it might need. I looked it over, and these are the preliminary evaluation photos.  When I received the guitar it sat for days before I finally opened the box, because after ascertaining that the box was delivered in good condition, I realized that I had a huge backlog of repairs in my shop. So finally opened the box on 6/24 after sending one of Phil's other guitars--the Yamaha FG180-1--back to him. The photos below represent the preliminary evaluation. 
 AS RECEIVED 6-24-2015

The purpose of this photo is actually an attempt to show the body bowing at the bridge. It is difficult to see, but see the rounded swirl effects of the lights? It shows a large bulge in the body below the bridge. Yes...difficult to see. The next two photos are attempting to show the same thing.

This photo shows how pronounced the bulge is. In fact, you can see the impression on both sides of the bridge where the x-bracing is.

Here, again, difficult to see, is the bulge. It can be clearly seen with the naked eye, but difficult to capture with a camera. This leads me to believe there are braces that have detached on the inside.

This simply shows a minor nick in the top finish on the right side of the lower bout.

In this photo the effect of the bulge is that the pressure of the pull on the bridge pins--which were leaning forward, have cracked the bridge. This aft crack stops at the inside high E bridge pin.

On the other end of te bridge, a crack can be seen propagating from the second string (B) bridge pin to just beyond the break-over at the bridge edge. One smaller crack can be seen at the end of the saddle slot.

The intent of this photo, and the adjacent one, is to show that the nut is not original. It is too short.

View of the other side of the nut--showing that it is indeed too short.

Small nick in headstock is of small concern. Probably not worth addressing.

Tuners on the sister F-27 are Grover. These obviously are not, but they appear to be original. I had a F-312--which had the same tuners, but in silver. These may be normal for the F-2712.

This appears on the lower bout, and is definitely a result of impact damage. The guitar was either bumped hard or dropped. The adjacent photo is showing the same thing, but an attempt to get a clearer photo.

Impact damage on back side of lower bout edge.


End pin at the aft end has been replaced with an end-pin jack. At some point the guitar may have been modified to plug into an amplifier. Peering inside, reveals that the jack has been modified and there is no wire running to it.

This photo was taken with a portable USB camera inside pointed at the 'X-Brace'. It shows the suspected separation/detaching of bracing is a reality. The gaps can clearly be seen--even with the strings loosened. 


Aft of the X joint, more separation of bracing on the right leg of the x-brace. The red bracket above attempts to show the length, but the bright light of the camera washed out the rear-most part. The gap can clearly be seen at the top left corner of the photo.

This photo also shows separation/detachment at the left x-brace leg. 

The only purpose of this photo is to show that the electronics and aft (inside) end of the end-pin jack is modified to remove the solder contacts and all that remains is the dummy jack. I suspect this was a 'repair' to avoid having to plug and re-taper-drill the hole for a regular end pin. Electric jacks require a 1/2" (or 31/64") hole for end-pin jack mounting.

This photo shows (circled) delamination and cracking of the due to the detached bracing and pulling up of the top. Cracking in a laminated guitar is rather rare, since it takes a lot of pull under constant tension, over time, with detached braces, to make this kind of damage. It can however be repaired. Click the photo to see enlarged view. 

Added on 8/25/2015. Upon review of the underside of the bridge, I found that there is epoxy residue. The bridge screws (now removed, but shown above) were VERY DIFFICULT to remove. The bridge has been sanded thin, and the bridge plate has excess epoxy on it that must be removed, and the entire front edge of it is chewed away. A reinforcing plate will be needed. All do-able stuff.

Added on 8/25/2015. Better depicts the separated bracing. Hole shown is the adjusting hole for the adjustable saddle.

Added on 8/25. Other underside of bridge showing residual epoxy. It is all over the treads of the bridge screw. Although removed at the time this was posted, removal was difficult. Also seen is the missing front edge of the bridge plate. The position of the bridge plate may have been off from the factory, and the continual rub of string beads may have chewed the edge away.

Added photo 8/25. Shows with better clarity the separation of bracing on the opposite side.

I removed strings, bridge pins, saddle, and bridge screws on 8/25, then glued one of the larger cracks in the bridge. (not shown). On 8/26 I sanded the bridge plate, then proceeded to prepare the guitar for gluing the detached braces.

A description of what you see above is in order. I first sanded between the braces and sound board inside the guitar (yes this IS a challenge). That is an extra step that I feel is necessary to make this repair permanent--a good wood-to-wood glue bond. I have all the equipment prepared and laid out first. I do a practice run without glue--just to be sure I don't run into problems. I put a paper towel inside and tape it in place to catch any glue that might drip.  Application of glue inside is next with the guitar upside down. I let the glue run down the length of the brace, then work it into the joint between the brace and sound board using thin nylon strips (made from a book report cover). After wiping away the excess glue, I put clamps in place. You can see the strips of wood running at an angle outward from the clamp. These are positioned right over the brace to insure even pressure clamping. The strip across the bridge does the same thing--spreads the clamping pressure over a broader area. The clamps are at first snugged. Then I put the strip across the length of the lower bout. I draw it down on both sides using the 6" spreader clamps. This removes any bellying and puts the top in a position to dry. I then tighten the brace clamps.

This is a view of the clamped brace on the inside. I took the photo using a mirror. You can see here how liberally--yet neatly---the glue is applied to the brace. The paper towel in the bottom will catch any glue that might drip (doesn't look like it will based on this photo. I took the photo about 15 minutes after applying the clamps. If it hasn't dripped or 'run' in 15 minutes, it is not going to do so. Even this early on, I can see that this effort is going to be a huge success.

Bracing clamps removed today. Photos show a good secure bond. Then made a new bridge plate to reinforce what appeared to have been partially removed. I thought I took photos of the bridge plate clamped in place, but could not find them.

Only one photo taken--shows the re-glued bracing--to the lower left and lower right and above. Also in the back center the new bridge plate is in place.

I removed the nut, to replace it with one that was the correct width. This neck is about 1-31/32, and standard nuts are 1-15/16. So the narrower nut is very obvious. It is only a guide nut (there is a zero fret).  Whoever worked on this guitar before, obviously put the bridge on with epoxy. It will not come off. Also, a makeshift saddle was made, and the saddle slot was lengthened. When Phil and I first met, I had sold him a Conn adjustable saddle. He sent it back to me and asked me to put it into this guitar. This necessitated "undoing" the lengthened slot. So I made a piece to "patch" the nut slot. Below is the beginning of that.

Here, I've joined (glued) two pieces of rosewood to achieve the right thickness. I clamped these for about an hour to dry.


Here I have cut the piece to fit, and have put it in place to see how it fits. It fits well.

In this photo I have put glue into the slot and put the piece of rosewood in place. The glue is Titebond Dark Wood Glue. It dries dark and is easier to blend with the rosewood.

This is a photo taken from a different angle to show that the piece protrudes slightly. This was on purpose, so that once the glue is cured, I can finish it down flush. You will not be able to tell it was repaired, when I finish with it. I was able to put the "plug" only at one end, because the slot had been lengthened unevenly --all on the bass side.

I tried to finish the guitar by 8/29, because I thought I might be able to ship it back to Maryland. But it did not come together, so I'm still working it. Stay tuned...more to come!