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A few years ago I did a neck reset on a Gibson CF-100 and have wanted one ever since. I came across this one and decided to buy it. It has seen better days and needs some serious work but It will be worth it to me in the end.

First the question:

I will need to level the fretboard and so the first thing I am doing is removing the fret markers since I don’t want to sand through them or make them overly thin when leveling the board. The first 4 I removed using steam by placing a wet rag on the marker and a soldering gun. They were the most loose and came right out. The others are being stubborn.

You can see in the below pictures that there is some brown adhesive of some sort and it is pretty dried and cracked. I tried to dissolve it using water, vinegar and then acetone but nothing seems to effect it. Does anyone have an idea how to remove the markers without breaking them?

Next I want opinions and suggestions”

This is an early 1950 model because it has the silk screened logo instead of the MOP inlay with the flower pot. It is my understanding that there were only about 300 made with the silk screened logo. The FON number indicates that this was early in the run of 300 and I was told it was probably one of the first 100.

You can see from the pictures the top is in pretty bad shape. It has the typical crack at the cutaway and the sinking around the sound hole. The top has been cleared over and the bridge has been replaced and has gouges all around it where the wood was chipped. It is missing one brace on the back and most of the others are loose. Someone tried to fix it by gluing in a piece of wood next to the sound hole as well as trying to glue the braces back in but was unsuccessful. They also cut the wood away inside the rosette and did a very poor job at that. The wood is splintered and there is not much holding the rosette in. The good news is the sides and back are original finish and are in pretty good shape. The neck is also in good shape except for a very slight twist which I can get out by leveling the fretboard. It clearly needs a neck reset and frets but overall is pretty good and is all original finish. The binding is also in good condition on the back with no cracks or missing parts.

My personal feelings is the top can not be saved and should be replaced but before I get into doing that I am interested in your opinion on what you would do. I know it will not be a collector but it is still worth bringing back to life.

So... Opinions, Suggestions? Ideas?

Thanks
Bob

I got the rest of the fret markers out and the glue cleaned out of the routed holes. The reason the last ones were giving me a hard time is that I was trying to use the medium setting on my soldering iron. The first ones I used the high setting and as soon as I figured it out they came right out. I also managed to not damage any of them so they will be reused.

Next step is to loosen the fretboard extension and remove the neck. I pulled the 15th fret, drilled the holes. You can see my setup with the ceramic blankets in place. I heard about using ceramic a few years ago and decided to get some and give it a try. I will never go back to tinfoil an cardboard because these are soft so they won't scratch the finish and will shield up to 2500 degrees. You can see I have one cut out for the neck and another cut to protect the fretboard bindings. After setting it up I used my trusty cloths iron an in about 10 minutes I had the extension loose.

I moved on to setting up the neck jig and my old espresso maker and steamed the neck off. I guess I didn't release the extension right up to the joint because you can see I pulled some wood off but no big deal on this one since the top will be replaced.

More to come...

Cheers,
Bob

After the neck came off I had a fleeting idea I would try to save the top so I figured I would just remove the bridge while the top was still on the box so I precoded to remove it. As I pulled it off I saw why the original was replaced. The top was broken out under the bridge and the wood was completely torn up from the last bridge replacement. They didn't even bother to attempt a repair and i was amazed that the replacement even stayed on because there was hardly any glue holding it on. So that made my mind up that I wouldn't save the old top.

Next I routed the binding off being careful to just take off the binding and not get into the sides. With that done I used my heat gun out and released the top from the sides. Surprising this was probably the easiest one I have ever done. Considering the amount of glue that was slopped all over the inside of the box it released really easy and didn't fight me at all.

You can see what a mess the inside is so I will be spending a while removing all that glue. All of the back braces were loose except one, half of the top braces just fell off when I lifted the top but none are cracked.

I know how I will be spending my evenings the next week or so... cleaning old glue out an there is plenty to clean.

More to come:

Cheers,
Bob

Routing the binding and removing the top.

Note: this is not how I hold my router and don't recommend any one try it like that. I had to take the picture so it is just showing what I am using.

Cheers,
Bob

Looking at the inside it is pretty much a mess. Glue spread all over and the braces that were attempted to be repaired were loose and they never got clue under them. Having looked at the soundboard I just don't think there is any saving it.

So on to cleaning up the glue. I am using vinegar applied with a small artist brush and will use a chisel point and bevel point X-acto blades to carefully scrape the glue out. When the glue is removed I will apply a small ammout of vinegar and use a toothbrush to brush the remainder of the glue out of the graine lines. The kerfed lining is a bit more delicate since I need to remove the glue from the slots in the lining. I know that Gibson has a pretty bad reputation for sloppy work and having glue mess inside their boxes so my intent is not to clean everything out but just what I know is from the crappy repair (or lack of repair).

More to come...

Cheers,
Bob

So far, so good. I'm watching with interest!

_________________
"Act your age, not your shoe size" - Prince

Nice cleanup job and nice work in general. I'm almost done with a '49 J45 that had similar issues plus multiple cracks in the back and sides. Someone had sanded off the original finish and ruined the soundboard so it also got a new top. I'm following your thread with interest.

_________________
Steve Smith
"Music is what feelings sound like"

Now to remove that painted back reinforcement strip. Why someone would paint it brown is beyond me but it has to go...

Because it is right over the back seam I can't use heat or vinegar to remove it because I run the risk of ungluing the back seam along with it so I will scrape it off using one of my chisels. Note I am not slicing it for fear of digging down and getting into the back so I am using it like a scraper.

Now to make a new strip to replace the old one. I had a scrap of spruce top that I cut to thickness on my band saw and then cut to width. Fortunately by the tail block there was a piece of the original reinforcement strip that was loose so I pulled it up so I could get the profile correct.


Here you can see I have it cut and shaped.



It is the correct size and is ready to go in but if I glue it in now it will look like a new repair... not good...
(Notice that after I removed the old strip I cleaned up the glue and paint mess around it)


I need to age the new piece so I get out the Potassium Permanganate. If you don't know what this is, it is an oxidizer and it will do the same thing that time does to wood. It is not a stain so there is no need to try to mix up the right color. You can see I am testing it on a scrap piece of the same wood. Depending on the strength it is mixed up it will vary on how much it oxidizes.


This is the new piece next to the original back strip.


And here it is ready to glue in looking like it it fits right in with the age of this box. Arrg... Look at all the ugly glue mess that still needs to be cleaned!

I really like where you're going with this.

Thanks

Thanks, Its nice to know.


Lots of progress since business is pretty slow. Not that I don't like paying jobs but this is the stuff I really enjoy doing.

Moving on to the lower bout, both of the braces are loose an need to be removed so using a hair dryer to warm up the glue line I carefully run my palette knife under the brace and slide it along the length. I am mainly listening to the sound to make sure I don't hear any wood crunching. These braces were pretty loose so it was a quick job except where the globs of glue were.









Moving on to the last brace, I had to remove a glob of glue before it could come out.




This is one of the few braces that was tucked well under the lining so I scored the edge a few times and out it came.

After a lot of scraping the glue out I finally have it cleaned up. One thing to note I am not sanding anything on the sides or back. Just using vinegar and my X-acto blades to soften the glue and carefully scraping it away. I am then using a tooth brush to clean up anything left in the grain.

Here is the results


Next will be cleaning up the braces and making the new one. Since the neck angle was way off an the top had sunk in I knew there would be more to fix than just a neck reset. In fact the neck joint was tight and there were no gaps between the heel and the body. This suggested that the back had flattened out as the top sunk in so I knew the braces (which I plan on using) would need to have the radius re-sanded. I got my 12' radius dish out and that confirmed that the braces needed work. There was a slight gap when I laid them down on the dish.
Here are the braces and the stock for the new brace.



Sanding the radius


I cut the new brace stock to length width an hight on the band saw and here I am shaping it.


Here it is to rough shape and ready to radius.


Here it is done but comparing it to one of the originals it looks way to new...


Gibson is known for rough braces and these are no exception so I wanted to try to match the new to the old.
I am using a saw blade protector as a jig to score the saw lines into the new brace. I just used a scrap of wood clamped under the plastic so I could slide the new brace and keep my lines parallel. I tested a few tools to create a similar line an this little screwdriver did the trick.


And here is the results after applying the Potassium Permanganate. After I shot this picture I decided the lines were a bit too pronounced so I used my mini scraper and scraped it to make it a bit more subtle. I then re-applied the Potassium Permanganate and then dusted it with a bit of white chalk to give it that bit of dusty look the other braces have.


More to come:

Cheers, and thanks for looking,
Bob

Next step is to glue in the braces.

I set up my self made Go-bar deck with the 12' radius dish covered in a towel since I leave the sandpaper in it. I also set up my HHG glue pot which is nothing more than a small crock pot with aquarium gravel and water. I find that holds and very even temperature.

Here are some pics of the process.






Here is the box with the braces glued in. Notice how the new parts blend in with the old.

Only a couple of things left to do on the back and sides.

Because I used vinegar to remove all the glue I need to neutralize it. Vinegar is very acidic and that isn't good for wood so what I will do is dust some baking soda on the inside which will sort of de-activate the acid. The added benefit to that is it will give it that dusty look back. I am using artists pastel sticks to tint the baking soda so it isn't white. I use an X-acto knife to scrape the color off so it will mix easier. A little gray and a bit of brown should give the look I am after.


I also mix up a darker color that will get dusted around the lining and along the braces to give it that "lived in" look.


I make sure I brush it into the grain pretty well since the main idea here is to neutralize the wood.


Then a little of the darker color around the edges and in the corners of where the braces meet the back.


And here is end results. The goal was not to try to age it but that is a small benefit. The picture doesn't show it very well but it now has a dusty look and doesn't look freshly cleaned.




More to come:

Cheers,
Bob

Next I need to fix the jack hole that someone put in the lower bout. I am surprised that it hasn't developed a crack since it was never reinforced. Lucky for me because it will make it easier to repair.

The first thing is to clean the area really well so there isn't any wax or grease on it.



I have done a few of these repairs and I like to square off the hole rather than try to cut a round plug to fit.
I have selected a scrap piece of Mahogany that matches the grain pattern as close as I can get. Fortunately the box is open so I can just hold the wood up to the hole an mark where I want it to be.


I have cut it to size and sanded the thickness so it just sits proud of the outside




Next I make a cleat that will go inside the guiar. I bevel the edges so it looks nice and glue and lightly clamp it. After the clamp is removed I brush some Potassium Permanganate on it so blends in a little better (hey why not?)


I then glue the new plug in place and clamp it lightly. When it is dry I place blue tape all around it to protect the finish. I use this as a guide to sand down to and when I hit the tape I will switch to scraping.



Now I switch to a thin low tack tape that I have. It is about the same thickness as scotch tape. I use my mini cabinet scraper and scrape it down until I just touch the tape again.


With the tape removed I lightly sand the edges with some 1200 grit paper to smooth everything up. You can see I sanded the finish around the hole also. This will give the new lacquer something to bite into when I am ready to spot the area in.

Next I need to make it blend in a bit better with the existing Mahogany. I use the side of a new X-acto blade and scribe in some grain lines by just continuing the lines from the original wood.


Then I use some grain filler which I mixed up to match. You can see the grain appears to follow right over the plug.


A little stain and it is starting to blend in. I also tinted the stain with Mixol tints to match closely to the original finish.


And now I will drop fill the area several times and after it dries I will block sand it with 1200 grit paper and lightly spot the area in with my airbrush and buff it out. I won't do the final sanding and finishing until I am ready to do the top so that will give it plenty of time to dry.
But this is how it looks after drop filling a couple of times. It still needs a few more to get to the point where it will be leveled.


Thanks for looking,
Bob

Looking good. That was one well played guitar. I remember these when they came out and always like them too.

_________________
Another day, another dollar.

Thanks Shaw, I have thought this was a very cool guitar since the mid 70's when I first saw Leon Redbone. It wasn't until I had one in my hands that I really wanted one. I was 3 years from being born when this guitar was made.

OK, so progress has been a bit slow with Thanksgiving and family stuff but I have made some progress.

This is my 6th guitar that I have either removed the top or the back and I have always made a temporary jig to set the neck angle so I decided I would make one that will be adjustable for different size guitars. I need a way to level out the bottom and lock it down so I know it is square. Once that is done I also need to lock the tail block down so I know the only thing that will adjust is the heel block. From prior experience I came up with this jig. It isn't unlike a binding jig but does have the ability to put a bolt through the end pin hole and with a couple of small shims I am able to keep the tail block from moving.



This is the bottom so you can see how I adjust the arms. The wing nuts are recessed so the jig will lay flat on the bench.


An this is the clamping device I came up with. It is nothing more than a piece of threaded rod that pushes up against a strip of Hard Maple. I used the felt pad as a hinge so the strips stay with the jig.


And here is the guitar body clamped up in the jig.


I temporarily shimmed up the dovetail neck joint so the neck fits good and snug and then I checked the left/right alignment of the neck.
This is before clamping the guitar down in the jig.


And this is after. You can see that just by squaring up the body the neck came right in line. (Look at the center line on the tail block and not at the reinforcing strips for the back, the angle of the pictures make it look off but it is actually right on the line)



The next step will be to make the internal adjusters that will allow me to set the neck angle but I will need to know where to set it so I made this template with the profile of the top radius plus the thickness of the top and I added another piece that is the thickness of the bridge.
You can see now I have the guitar in the jig it isn't too far off.

I decided to use a set of German Spruce soundboards I got a while back. I bought them from a local Luthier named Herb David when he retired. He had them stacked and stickered for over 50 years so they are almost as old as this guitar. I joined the plates and thicknessed them down to about 0.140" and cut out the shape and scraped them down close the the final thickness.





The thing I have been working on is trying to figure out how to do the bracing for the top. The original design had the UTB just butted up to the upper part of the X bracing and not tucked in under the lining. I have seen other examples of this same guitar where the UTB stops at the cut-away and doesn't even support the entire width of the upper bout. Clearly this was a fault in the design and probably why this guitar was only made from 1950 to 1959.

So I fired up LibraCad and started drawing up the plans for it. My intent is to keep it as original as I can (no carbon fiber) but still beef up the area around the cutaway. Once I finish the drawing I will print it out full size and lay it out on the top. The one thing I had to figure out was were the sound hole is located exactly. Who ever repaired it before cut the hole up to the rosette. I a guessing because part of it was worn away from playing it hard.
Here is the original layout and you can see the UTB just stopped at the upper X brace. That was the exact spot that the braces let loose and the top was caving in.



Next step is to finish the bracing and make the rosette so I can get this box closed up.

Thanks for (looking)... (over 400 views and 4 comments)

Cheers,
Bob

Bob, Thanks for sharing this. Your techniques are very impressive. I hope you keep showing us how this restoration unfolds. I'm eager to see how it turns out.

_________________
Steve Sollod (pronounced sorta like "Solid")
www.swiftcreekguitars.com

Bob - you are not just repairing or restoring this old axe. You are conserving it just like a museum might preserve a historic artifact. Color me very impressed!

_________________
"Act your age, not your shoe size" - Prince

Thanks Steve, Yes I will be posting the entire process here. I am currently trying to decide the best way to deal with the UTB. After searching the entire internet for pictures of this guitar I see that Gibson was not entirely consistent with the placement of the sound hole. Some of them the rosette is under the fretboard extension and some are moved down by up to 1/4". Mine has about 1/8" between the two so I am looking at moving it a bit farther down so I can make the UTB a bit wider and also lessen the angle it was on. I hate to stray too far from what this specific guitar is but I also don't want it to fail in a few years either.



Thank you very much Chris, My intent is to redo this guitar as if it had never been assaulted by the person that attempted to fix it. I am fortunate to know a lot of the little tricks of restoring antiques furniture which are not so different from this.

I will be posting more when I start doing something rather than figuring out how I am going to do it...

Cheers,
Bob

Great stuff!

Been a bit since I posted an update on this so I will catch up on where I am.

I decided to move the sound hole down far enough to give me a bit of room to make the UTB a bit larger and also tuck it under the lining (It was just butted up against the upper X brace before). So I revised my drawing and this is what I came up with. This is transfered from the cad drawing to some heavy stock for my layout template.


Next I made the UTB




Compared to the old one:


Then I needed to put the saw marks in that Gibson is "in"famous for:
NOTE: I am doing this with my saw UN-PLUGGED and am just using the scrap of wood to rotate the blade to make the marks.


Next I need to give it a coat of Potassium Permanganate to give it some "age". I also used my airbrush to give it the typical Gibson overspray when they do their bursts. I never could understand why they didn't mask the braces when they did mask the inside of the back...
Here is is compared to the original.

I am a bit out of sequence since you probably noticed I have the sound hole cut in the above shots. I left off with my previous post talking about the UTB so I figured I would show that first but I did make and install the new rosette.

Here is my test piece to make sure I have the correct sizes after being glued up.


Next I make the mould that is exactly the size I need. Here I have the rosette almost done. Because this is plastic I am using acetone to "glue" them together.


Because it is completely exposed I have take extra care where the ends meet to get them to line up.


Next is to route out the channel and trial fit.




And then scrape down.


And cut the hole.


Next will be to move on to making the new X braces. I decided to make new ones because the old ones were so warped out of shape by the time I re-radiused them there would not be much left. I measured them and they had bent to about a 9 foot radius because the top had bellied up so much.

More to come...

Cheers, and thanks for watching.
Bob