Repair of 1975 Gibson J-45

If you have a string instrument of any kind that needs fixing, a mistake you made in building a new instrument that you need to "disappear," or a question about the ethics of altering an older instrument, ask here. Please note that it will be much easier for us to help you decide on the best repair method if you post some pictures of the problem.

Re: Repair of 1968 Gibson J-45

Postby Gordon Bellerose » Sat Sep 22, 2018 2:45 pm

Great discussion on repair ethics.
I believe that whether you repair for posterity, or playability depends on the owner.
What does he want?

In this case, the owner is a player and wants to play the instrument.
I think the repairs that are being done, are being done in the least destructive manner while at the same time bringing the guitar back to a new, better life.

I'm firmly in the boat with all of that. A guitar is meant to be played.

And as Barry noted, this instrument is not a greatly valued vintage guitar anyway.
Things may be different if it was an earlier version.
I need your help. I can't possibly make all the mistakes myself!
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Re: Repair of 1968 Gibson J-45

Postby Ryan Mazzocco » Sat Sep 22, 2018 2:48 pm

Loving this thread. Thanks for sharing!
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Re: Repair of 1968 Gibson J-45

Postby Mario Proulx » Sat Sep 22, 2018 11:58 pm

Let's be realistic. None of the that era's Gibsons are, or will be highly valued "collector" treasures. Making it playable and enjoyable for its owner, and future owners, actually raises its value and likelihood that it won't get hacked, left under the bed to be inherited by someone who will sell it for crack money, or simply tossed into a dumpster.

That said, I encourage you to try a few things with the bracing before giving-in and pulling it for a complete re-brace. You can do this before the re-bind, so nothing is lost if you do decide to re-brace it.

I've had decent success pulling that massive bridge patch(as large as it is, I refuse to call it a bridge plate..!) and replacing it with a nice, small maple plate.

Then cap the main x-brace with a Martin-style cheese cloth and glue reinforcement to stiffen that area. I would usually tell you to cap it with wood, but the braces are rounded.

Next, reach-in and snap off the lower leg of one of the second x brace's legs, the shorter one. It's a reach, so use slip joint pliers or something. They always snap-off cleanly...

Don't bother scalloping the main x braces but instead, taper them from their intersection to a feather at the rear-most points(if you can reach...)

Now string it up, and let the owner(or you, or the radio) play it a few weeks. Betcha dollars to donuts you'll all be surprised...!

If you don't like it, -then- re-brace.
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Re: Repair of 1968 Gibson J-45

Postby Barry Daniels » Sun Sep 23, 2018 9:56 am

Mario, thanks for the suggestions. I don't see a way to remove the bridge plate because it is surrounded on all sides by braces. There is no way to get my bridge plate bent chisel under the edge to start the removal process. Also, those old plugged pin holes probably lock the bridge plate to the top and maybe even the bridge.

How do you remove these type of bridge plates?
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Re: Repair of 1968 Gibson J-45

Postby Mario Proulx » Mon Sep 24, 2018 7:51 pm

They're usually falling off.... ;)

Use a finger plane to carve away enough of it to reach under.
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Re: Repair of 1968 Gibson J-45

Postby Mario Proulx » Mon Sep 24, 2018 10:48 pm

Or snap off the short leg of the lower x brace. That will gain you access to the patch...
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Re: Repair of 1968 Gibson J-45

Postby Barry Daniels » Tue Sep 25, 2018 10:52 am

That is a very interesting approach but unfortunately I won't be using it on this particular guitar. I took the fingerboard off at the beginning of the job. So I would have to pull the tone bar and bridge plate, put the fingerboard back on to hear the guitar, then take the fingerboard off again to re-do the binding. So in this situation that would be additional work when the goal for this procedure appears to be reducing the work load. So I am jumping into the deep end and will pull the top of this J-45 to fix her up good. But I will keep your technique in my quiver for the next time a Norlin era Gibson comes into the shop. Thanks for the suggestions, Mario.
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Re: Repair of 1968 Gibson J-45

Postby Barry Daniels » Tue Sep 25, 2018 7:13 pm

Back in the shop after being in Phoenix for 10 days. I let the neck rest and stabilize during this time which I believe is helpful. Next up is removing the neck. I am always looking for better ways to upgrade my tools and techniques. Our favorite tool supplier has a new tool for neck removal that is a copper stick that inserts into a soldering iron. The benefit is that steam is not used so finish damage should be minimized. The heat stick is fairly expensive and they did not offer a version for my Weller iron. I also feel that it should be necessary to have a heat stick on each side of the dovetail so I decided to make a couple of them, one for my Weller WP25 and a lacquer stick iron which is similar to a soldering iron. I bought a couple of pieces of 1/8" diameter copper rod and then made some fittings for the ends that fit into the irons. The fittings for the solder iron rod were three pieces of 1/4" copper water tubing. The two inner pieces were split, trimmed, and crimped around the rod and each other to achieve a good fit. The last piece of 1/4" pipe was left whole because it was the diameter needed to fit into the solder iron. The pieces of copper tubing fit together tightly.

The rod for the lacquer stick iron required a brass fitting to be turned to size. All the parts for both heat sticks were silver soldered together and placed into the irons.
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Re: Repair of 1968 Gibson J-45

Postby Barry Daniels » Tue Sep 25, 2018 7:15 pm

The heat sticks were inserted into slightly larger holes drilled at the end of the dovetail and plugged in. The neck was held in a vice in order to elevate the body above the workbench. As the dovetail joint heated up at several intervals I squirted a few drops of water into each hole as described in the Stew-Mac instructions. The slight amount of water was not enough to cause steam but it appeared to help soften the glue.
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Re: Repair of 1968 Gibson J-45

Postby Barry Daniels » Tue Sep 25, 2018 7:18 pm

The elevated body allowed me to wiggle the body to get a feel for when the joint got loose. When everything felt soft and loose I applied a bit of side to side pressure to the guitar body and held it there for a few seconds. I could see the sides of the neck heel pull away slightly from the body and then the body lowered about 1/8" from the neck. I pulled the irons out and the body fell cleanly from the neck. My irons are not high wattage versions so it took 30 minutes to achieve removal, but it went well and there was no finish blushing.
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Re: Repair of 1968 Gibson J-45

Postby Barry Daniels » Tue Sep 25, 2018 7:24 pm

I also took off the shrunken pickguard with more heat and pallet knives. The pickguard had been taken off by someone in the past and there was some old tearout of the top. But the deep one on the left side of the picture was my doing.

This photo also shows the stain someone applied to the top that was exposed when the shrunken pickguard was reglued.
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Re: Repair of 1968 Gibson J-45

Postby Barry Daniels » Tue Sep 25, 2018 7:25 pm

Took a small scraper to remove some of the glue left behind.
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Re: Repair of 1968 Gibson J-45

Postby Barry Daniels » Tue Sep 25, 2018 7:27 pm

I peeled the spruce tearout off the back of the pickguard and reglued it.

I will have to fit some spruce into the other tearouts to repair them. I plan on brushing some lacquer into the pickguard recess, making a new, slightly larger pickguard and using adhesive film to attach it.
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Re: Repair of 1968 Gibson J-45

Postby Mark Swanson » Wed Sep 26, 2018 11:41 pm

That's great work, Barry! I love the neck removal part!
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Re: Repair of 1968 Gibson J-45

Postby Barry Daniels » Thu Sep 27, 2018 12:08 am

It was the cleanest neck removal that I have ever done. Pretty happy with the homemade heat sticks. The only downside was they are soft copper so they bend easily, especially when hot. But they bend back straight easily too. I noticed that Stew-Macs heatsticks are hardened copper. But I am not quite sure how I could harden mine. You can't heat treat copper like you can steel. I have read that the only way to do that to copper is to work harden them.

One more thing, Mark. You were absolutely right about this guitar not being quite so old. They had a date stamp on the end of the neck tenon of Jan 23, 1975, placing this guitar right in the middle of the Norlin era. I guess I will have to correct the title of this discussion.
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Re: Repair of 1975 Gibson J-45

Postby Mark Swanson » Fri Sep 28, 2018 7:33 pm

I am excited to find out how nice the guitar will be after you are finished with it!
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Re: Repair of 1975 Gibson J-45

Postby Barry Daniels » Fri Sep 28, 2018 8:39 pm

You and me both, brother.

I think I will do an A/B frequency chart to try to document any improvements.
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Re: Repair of 1975 Gibson J-45

Postby Barry Daniels » Wed Oct 03, 2018 12:04 pm

A little progress. Got the tearout under the pickguard patched.
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Re: Repair of 1975 Gibson J-45

Postby Barry Daniels » Wed Oct 03, 2018 12:06 pm

And I decided that the bridge would be easier to remove before I take the top off. Since the bridge is too thin and has poorly cut pin ramps and saddle slot that it was not worth saving. So I took a router to it to reduce it to veneer thickness.
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Re: Repair of 1975 Gibson J-45

Postby Barry Daniels » Wed Oct 03, 2018 12:10 pm

The thin veneer was easily removed with heat and pallet knives. (Note: Having the bridge reduced to a veneer allows it to bend during removal so you don't have to apply near as much heat or prying pressure. Also the heat soaks down to the joint much quicker.)
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