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Moving on to the X braces. I am going to make the new X-braces using the old ones for a template, the only difference is I am going to make them just a bit taller than the originals to give them a bit more strength. I am also going to use the same joint that Gibson used which is the braces are shaped prior to cutting the half lap joint and they use small shims to fill the gap with a cloth patch over the X.

Here is what the old joint looks like.




I cut the new braces and laid them out on my template and cut the joint and fit the wedges.






Next I scored the saw marks into them as I did on the UTB and gave them a coat of Potassium Permanganate. I also got my airbrush out and sprayed the typical messy over spray that Gibson does.


I transferred the position from my template then glued them in.

I put a new radius on the other braces and glued them in also. I made a bit of a mistake in that I removed the excess hide glue when I installed the braces, Gibson seems to always have a glue mess. It just slipped my mind and I forgot to leave them alone.

Here is the top with all the braces installed and I loaded up my airbrush with Potassium P and dusted the inside to give it that aged look. I was very careful not to get it wet since I didn't want any warping (wetting one side and not the other). It took about 4 light dust coats to give it the nice aged brown look. I think the new top and X braces blend in pretty well with the original tone bars and small side braces.

Here it is next to my bracing template.


And here is a close up. You will notice that the color has toned down a bit from browns to yellow/brown. The PP takes a little bit to oxidise the wood and freshly put on it goes from purple to brown to yellow/brown (yes it is deep purple when you mix it up).

As A sidenote: I learned about PP when I was at Kendall College of Art. Movie studios use this to age wood for sets. Specifically in Westerns where they wire brush the wood first and then paint it with PP and it gives it that sand blasted weathered look.



More to come...

Thanks again for watching.
Cheers,
Bob

Next step is to install the bridge patch. I decided to make it like a normal size bridge patch since original one was only 1" wide and I am sure that contributed to the lower bout bellying up and the waist caving in. You can also see I have installed the flat braces around the sound hole. The original didn't have these but it will help. I know I am deviating on a few things that were not original but the things I am doing will help make sure this is the last time it will need any work for a very long time.



After the glue dried on the bridge patch I started setting up for installing the top. I put the body in the jig I made to level up the back and then put a shim and bolted the tail block to the end piece on the jig. I then made up the stretchers to maintain the width of the lower bout at 14 1/4" and the stretcher that will allow me to adjust the neck angle.

Here it is all adjusted and ready to go.


And a shot of the template I made that has the radius of the top plus the thickness as well as the bridge hight (the little added piece). I have the dovetail shimmed so the neck fits snugly in to the joint and I laid my straight edge on the neck and the neck angle is set almost perfectly. This is a good shot of how I made the stretchers. The side to side one has 2 end blocks that I just cut a mortice that the stretchers just fit in. I made it all so it would come out of the sound hole after the top is glued in.


And I have the center line marked on the neck and checked for the side to side angle. You can see it is dead on center now that I have the neck angle set.


Next step will be to cut the channels in the lining for the braces and make sure the top fits perfectly on the box.

Coming Soon...

Again, thanks for looking...

Cheers,
Bob

Bob, thanks for the detailed write up. I'm enjoying following along.

_________________
Steve Smith
"Music is what feelings sound like"

Next up is closing the box up and turning this into a guitar...

Here is a pretty good shot of the jig and the tail block bolt that goes through the strap peg hole. That stabilizes the tail block so I could adjust the neck angle. The clamping caul is taped up and ready to go. This will even the clamp pressure when I glue the top on and keep the bars and spool clamps from marking up the top.


I could tell everything fit tightly but I couldn't quite tell if the heel block was mating up so I chalked it and fit the top on. Here you can see that one side was not quite fitting so I scraped the one side and then it fit nice and tight. This shot was before scraping.


Glued and clamped.


I love my phone because it lets me get a good view of the inside to check for proper glue squeeze out. It also beats trying to inspect the inside of repair work with mirrors and lights.


Now let it set over night and check the results.

Next day I remove the box from the Go-bar deck and trim around the dovetail so I can fit the neck on to check my work. Notice I have not removed the frets from the neck yet because it will give me a better reading of where the neck angle is.



With my temporary shim in the dovetail joint you can see the neck angle is now almost perfect. I will be able to dial it in pretty easily when I fit the neck on.


And the side to side alignment is right where I wanted it to be.


You can just see my center mark in this shot.


Next thing is to trim the edges flush so I can route the binding channel




And it is starting to look like a guitar now. I think this 50 year old German Spruce top is going to really make this guitar sing!



Now to prep the perfling and binding and cut the channels.

Thanks again for Looking...

If I don't get an update before Christmas I hope you all have a Merry One (at least those that celebrate it).

Christmas Cheer,
Bob

I'm really enjoying this one Bob. Merry Christmas!

_________________
Steve Smith
"Music is what feelings sound like"

Cool stuff, My first re-top was a late 40's J-45 that looked like someone sat it on a hotplate and burned a very large custom sound hole (through the top and bracing), these old Gibsons really get abused

That's great. I really like the techniques you used to give that aged look, very clever.

Doing great so far!

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

Here is an update, I was able to put some time in it between holiday obligations and got the perfling and binding on.

I cut the binding channel and managed not to chip anything out. I decided to do the cutaway first since I needed to pre-bend the plastic binding. The compound radius on the cutaway just wouldn't let me do it without bending it first so I traced out the curve and made a jig so I could heat the binding up and bend it around the form.







I glued the perfling around the entire guitar so I could mate up the black and white at the horn.
And then installed the binding to the cutaway.



Next I bound the body and let it sit overnight.


I used Acetone on the joint where the binding meets at the tip of the horn to be sure they were connected. I just used some tape to put pressure on it while it dried.



Now let it sit a day and let it dry and then I can start scraping them down.

Time to scrape them down. I used a single edge razor blade that I turned a burr on and made it little scraper. I also dulled an rounded off the end I will not be using and covered it with a layer of blue tape. This will keep me from scratching up the finish on the side and let me scrape the bindings down to the thickness of the tape.





This stuff is fun to scrape but it gets a static charge and sticks to everything so I keep my shop vac handy and suck it up as soon as It starts getting in my way.


When it comes to the end of the cutaway I have to mate up the new and old so I scraped and sanded them together to get a nice blend. I will be tinting the new white binding to match the old so they should blend in pretty well.


And here it is all scraped up to the thickness of the tape on my blade. I will go over it again just freehand to flush them up because I will not be finishing the sides or back so I need a smooth edge at the transition of wood and binding.


Now I will be starting on the fretboard.

Stay tuned...

Cheers,
Bob

You are an awesome possum.

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

Next up is to remove the frets from the neck, repair the divots and level the board.

Fist is to remove the frets. Because this board is really dry I needed to get some moisture in it before I started pulling the frets so while was working on the body I have oiled the fretboard a couple of times staying off of the routes for the markers (remember I removed those as one of the first things I did on this guitar).
These are the cutters I use for removing frets, Both are just Harbour Freight cheap cutters that I ground the faces down so I can get under the edge of frets. I use to have a nice set of end cutters but they broke so I opted to go the cheap route and when they break it won't get mad... I have had these for a couple of years now and have done a number of fret jobs so it doesn't always pay to spend big bucks on tools... (besides these look strikingly similar to ones I have seen for 10 times the price but they are called Fret Pullers and not End Cutters)



I use my old trusty 40 year old Radio Shack adjustable soldering iron to heat the frets.


And gently coax the frets out...




A little more chipping that I had hoped for but no big ones and only a couple that I glued back down right away.
Looks like she's been rode hard and put away wet but it will come back to life...


A quick sanding to de-burr it...


More to come...

Thanks for looking
Bob

Now to repair the divots.

I use a method very similar to Frank Ford's in that I slice the wood in the bottom of the divot but I don't try to bring the wood fibers up even to the fretboard. I also don't use CA glue, I use Titebond III. I didn't take pictures of the whole process but it goes like this:

I slice the wood up to the edge of the divot mainly to give the filler some tooth. I cut it pretty deep and pull some of the fibers up then mix up a small amount of sanding dust I save from the board and glue. I push it into the open fibers but I don't fill the divot. I let it dry for a couple of hours and come back in and do the same thing, re-scoring the low spots. I have found that by re-scoring it with an X-acto blade gives the look of wood when it is finally filled and sanded since each batch I mix is slightly different. It also gives the next layer something to grab into.

Here is a shot after about the third fill and while I am sanding it.





And here it is done.





Next will be levelling the board and installing the fret markers

Cheers,
Bob
Cheers,
Bob

The first thing had to do was level the fretboard. I want to avoid having to cut new fret slots since the board is bound and I want to keep that original if possible. So I relieved the tension on the truss rod and checked how level it was and it actually pretty close to level. I would normally put a bit of back bow in the neck before I level it so when the tension is released it would have a slight forward bow but I already took some material off sanding the divots so I will keep it straight and put the bow in after the frets are installed. On a single action truss rod I like to be able to adjust the neck both forward and backward and it can be done after the frets are installed.

I used a piece of the fret wire I will be using and bent a little handle on it and then filed all the barbs from the tang. This is my depth gauge that I used to make sure I didn't take any more off than I needed to.


I didn't take any pictures of it but I used my "beam" with 120 grit paper on it to level the board first and then used my radius block to maintain the radius. Since it was pretty level to begin with it didn't take much.

Next I set up for installing the markers.

This is a pretty good shot of my neck jig I use for most of my neck work. It consists of 2 pieces the front is a cradle I made out of a 2X4 that I squared up and screwed and glued together. I routed out the "neck rest" before I put the 2 pieces together and then lined it with felt and a non-skid pad to keep the neck from moving around. The back is just a block I made to support the fretboard extension. I use scrap shims to compensate for the thickness of different necks. When installing frets I also put a shim under the heel of the neck to give it support so I am not putting any undue stress on the FB extension.


The original markers have a gold hue to them which I am not particularly fond of and they are made out of Pearoid which is a bit transparent I decided to use some white artist cardstock under them which brightens them up a bit. The old mastic was brown and pretty thick so I have some space to fill. The cardstock I used is artist grade which means it doesn't have acid it it (most papers do) so it will not yellow. The thickness was perfect to get the markers just proud of the fretboard. I started by cutting out the cardstock using the marker as a template and then mixed up some 5 minute epoxy. Laid a coat of epoxy in the hole and spread expoxy on the back of the cardstock. Put it in and put another layer on top of the cardstock and on the back of the marker. I did this to make sure I didn't get any air pockets or voids and then used a small block to press it all together I used my heat gun to speed the set time up on the epoxy.

Here are the first 2 done and scraped even with the board.


I installed them and before the epoxy was completely hard I scrapped them down as I went.




Finishied.


Next up will be fitting the dovetail and installing the frets

Thanks again for looking

Cheers,
Bob

Incredible. Thank you for posting this thread. I am picking up on all sorts of solutions that I never knew existed.

Next is to set the neck.

First thing I did was cut a new shim for the Dovetail. The original had a pretty large shim on the cutaway side and nothing on the other side. I saved the old shim and cut the new one just a bit thicker than the old.


I sanded the face of the dovetail to make sure it was clean and level and then glued and clamped the new shim in place.


Then I chalked the dovetail to check the fit. I use colored artists pastels because they are finer than just chalk but either will work. I like the color because it is easy to see.


And the first fit shows the high spots.


Then I pare off just the spots that have chalk on them. I am just barely taking any wood because it doesn't take much to go too far.


A little more and you can see the chalk line is covering most of the joint. The objective is to have the chalk even on both sides.


And a little more paring. I like to remove all traces of the chalk line before fitting the joint again. In some places I just use my chisel like a scraper to just barely remove the chalk and some wood dust.


At this point the neck is fitting pretty good and I have chalk marks evenly along the joint. I am just shy of having the neck fit all the way down and I have about 1/32" to go. I like to leave about that much so the joint fits really tightly when I glue and clamp it.
Here yo can see I have a bit of a gap at the bottom but it is just tight at the top. The other side fits pretty well so I know the neck is skewed to one side.

Looking at the center line shows how much the skew is. This is about where the bridge will sit.



So I floss the neck with a piece of 100 grit paper. I am trying to just take material off the top first and will then chase it down the side to make sure it is even and I don't put a hump in.


And now I have a nice tight fit.


And my chalk line on both sides of the joint are even so I know I have a good tight joint.



I flossed the neck on both sides with some 180 grit and checked the fit again.

And the neck is lined up almost dead center. This makes me happy


And the hight over the bridge is right where I want it. The frets have been removed so with the frets installed it should be perfect.


And it is starting to look like a guitar!




Thanks again for looking. I just saw this thread has over 1000 views so at least I know people are looking!

I hope you all have a happy and healthy new year

Cheers,
Bob

Happy New Year Bob. I've got to tell you that I've been enjoying this thread immensely and learning a ton. You do beautiful work.

Thanks for doing this Bob. You really did a fine job on filling the divots in the fingerboard (of course, you've done a fine job on everything else too...). I noted how you treated the upper transverse brace and the top of the x-brace - in terms of tucking them into the kerf binding. You have discussed this before and how you needed to address this issue in the restoration. You had noted that the UTB had been simply glued to the x-brace, rather than tucked. I assume that you decided that no other measures were necessary, with the exception of tucking into the binding...

Great job. Very informative as well as entertaining.
Thanks again.

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

Great post Bob .. enjoying each instalment

Thanks much guys, It is nice to hear from people that are following along with this.



I had never dealt with an issue like this before and was not exactly sure how to go about repairing it. Over at luthiercom.org I started a discussion to get some ideas. My objective was to keep it as original as possible. After much discussion I finally settled on moving the sound hole down just enough to get the UTB to completely support the fretboard extension. The original design had the UTB missing about 1/4 of the Fretboard extension because of the angle. From looking at a number of pictures of CF-100s I saw about 3 different placements of the sound hole so it was clear that Gibson was experimenting with this.

The other thing I did was make the UTB about 1/8" taller and about 1/16" wider which would give a lot more structural strength to it. By tucking it into the lining right next to the X brace I was able to create a butt joint up under the lining so they are tied together and locked in place. The one other thing I did was add the braces next to the sound hole which the original didn't have.

So I am hoping 50 years from now this one doesn't suffer from the same collapse that most of the CF-100s have had.

Again, Thanks for watching guys, It is nice to now that someone is interested.

Cheers,
Bob

Interested? Someone? I'm guessing every budding luthier/repair guy is printing off the pics and text in this thread!

I especially like the idea of using artist chalk. That allows for good contrast regardless of the color of the wood.

One thought, I bought an LED lit borescope like camera on a long lead that attaches to the laptop. $25. It's really handy for looking around on the innards.