Repair of 1968 Gibson J-45

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Re: Repair of 1968 Gibson J-45

Postby Barry Daniels » Sun Sep 16, 2018 12:01 am

I also want to show a photo of how I ran the carbon fiber rods into the truss rod recess. I took them about as far as possible into the peghead in order to minimize future neck breaks (aka: Gibsonitis). The exposed ends of the rods will be covered by the truss rod cover when complete.

I am going to let the neck sit for a week or two to see if it wants to move. Then I will pull it and do the neck reset.
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Re: Repair of 1968 Gibson J-45

Postby Barry Daniels » Sun Sep 16, 2018 12:10 am

Gordon, thanks for the questions.

My first jig used a guide bushing but it was impossible to place the slot accurately with this setup. I could not find a way to accurately judge where the slot would be. The new jig with the edge guide allows very precise alignment and the plunge base on my Colt router provides more accurate depth control.

I am not sure if the heat made much effect on the area of possible delamination. To be quite honest, I am not sure if there was much delamination to start with. The joint was well closed and if it was delaminated, it wasn't a very long section. But the carbon fiber slot removed most of the joint and replaced it with a new one. I believe this was the best possible solution. I tried to seep some CA into the joint at the bottom of the carbon fiber slot but it would not penetrate so I may have been wrong about this joint actually being loose. But I know it is tight and secure now.

Thinking about this some more, it may have been that the weakness I was feeling in the neck was solely a result of the fretboard being poorly glued and loose at the upper end.
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Re: Repair of 1968 Gibson J-45

Postby Bob Francis » Sun Sep 16, 2018 12:55 pm

This is a great thread!
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Re: Repair of 1968 Gibson J-45

Postby Barry Daniels » Sun Sep 16, 2018 12:57 pm

I recently got a MacRostie Binding Trimmer to use on this project when I get the binding replacement phase. I would previously size plastic binding by hand scraping and using feeler gauges to try to keep the thickness consistent. This was always fussy and time consuming and the results were never perfect. So out came the credit card and another tool added to the quiver. I used the trimmer to size those maple filler strips and it worked so well that I give the tool my highest recommendation. The device is basically a small router table with a precision controlled fence and spring loaded vertical and horizontal hold downs. I was able to quickly size the wood strips with a precision of nearly one thousandth of an inch. For the work I do this thing is a game changer.
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Re: Repair of 1968 Gibson J-45

Postby Barry Daniels » Sun Sep 16, 2018 12:59 pm

Thank you Bob and Mark.

Overnight I was thinking about the neck some more and I think what I may have been seeing was glue creep of the parts instead of delamination. The excessive compression of the truss rod nut and washer may have made the center lamination creep downward and the truss rod filler strip move upward. So the problem may be minimized a bit but the restoration work does not really change. However, I really try to understand what is going on so that my efforts don't get misdirected. A call out and thank you to Gordon for prompting more exploration of this issue.
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Re: Repair of 1968 Gibson J-45

Postby Mark Swanson » Sun Sep 16, 2018 2:38 pm

That's very good work Barry! Nice. I am not so sure about it being a 1968, it may be newer, but it is a Norlin era Gibson. Those are the ones with the double X-brace and the huge bridge plate. Have you considered doing anything with that? Since you have to fix the binding, you might be able to pull the top and re-brace it, after that it would be an outstanding guitar.
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Re: Repair of 1968 Gibson J-45

Postby Barry Daniels » Sun Sep 16, 2018 4:28 pm

Hi Mark, I am glad you weighed in here. The serial number dating site sort of chocked when I input the serial number. But it states that in 1970 they switched from orange labels to white. So this orange label guitar indicates it is pre-1970. But it does have the double-X and large bridge plate.

The strange thing is that someone did some really funky work on the bridge. Please look at the following pictures. There is an inset around the bridge pins that looks like black plastic and it is the size of the adjustable saddle monstrosity. And the photo of the bridge plate indicates that the bridge pins were moved and the old ones were plugged. It is a mess and I am not sure of the best direction. I can't remove the bridge plate due to the double-X brace butting up to all sides. I at least need to use a Stew-Mac bridge saver and try to restore the damage around the pins. I am also considering replacing the bridge. The existing bridge is really thin (.2" thick) and the saddle slot is poorly cut and too shallow.

Didn't most of these J-45's have reverse belly bridges? Could someone have taken the bridge off and turned it around which resulted in all these weird things? This is an area where I really need some advice from those more knowledgeable about Gibsons.

Your idea to pull and rebrace the top is intriguing but I am not sure my client is willing to go that far. But the bridge issue is still up in the air.
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Re: Repair of 1968 Gibson J-45

Postby Barry Daniels » Sun Sep 16, 2018 5:44 pm

This 1970 J45 on YouTube is a very similar looking guitar although I can't tell if it is an orange label or not. It does have the bridge in the normal belly down position like mine.

https://www.youtube.com/watch?v=uDQeOaHmwaI

It could be that someone routed out the area around worn bridge pin holes to install that piece of black material. And that somehow necessitated moving the pin holes slightly. One other piece of evidence that indicates that the original bridge was belly down is the foot print on the top which shows no sign of a belly up orientation.

The more I think about it the more I want to pull the top and rebrace it. Now would certainly be the time since the binding will be removed. Darn you Mark! ;-)
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