Bought a beat up J45. Mahogany/spruce, reverse belly bridge, mahogany neck block, gold block logo. 50's?

All back braces are loose/ completely unglued.Center strip is missing entirely. Took a peek inside and it seems nearly every single brace in this guitar will have to be reglued. Guitar was dropped and seams have popped open... How do you all approach a guitar that needs extensive work inside the box? Its not just a brace or two, but pretty much all braces.

My first thought was to remove the back of the instrument. Thoughts?


Tags: J45, brace, repair

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Did it recently on a 50's LG0  almost every brace loose.

The back came off easy, no way could the repairs have been done adequately without removal

I just took the back off a Silvertone archtop yesterday, using a very controllable heat gun - I set the temperature at 170 degrees, and just slowly heated the thing. It came off beautifully with no finish damage or searing of the wood. So much easier than using a heat lamp or an iron and a towel!

 I also believe it would be much easier to remove the back for the repairs.  Before you do, it might be a good idea to, at least, make a tracing of the body shape. It would be better to make some sort of form to support the sides in shape so the back will fit more easily when it comes time to glue it back into place. 

Pictures? We live on pictures.

I'll get some pictures up asap. Thanks guys.

Randy, Can you tell what kind of glue you have in the guitar? With your description of wholesale popping off of wooden parts, I suspect that it is Weldwood plastic resin. If it is Yellow or Red and resembles expanding Urethane foam, that is what was used, it's a Urea-Formaldehyde chemistry. The glue would be bubbly, cruble easily and it won't respond to heat, water or solvent, basically, an irreversible glue. If it was on my bench, I would remove the back and clean as much of that crap off as you can, scraping and sanding, then go back together with hot hide glue. I would be interested to see any pictures you can post.

Paul, do you mean that Gibson used U-F/Weldwood in those years? I'm curious, because I have a '59 Gibson, the braces etc. glued with a reddish, bubbly, crumbly glue....with many loose spots when I bought it.

Here is a picture of some Red U-F in a 61 Kalamazoo Epiphone FT30 Caballero. The back came off real easy without damage to any kerfed lining.

This is a shot of some Yellow U-F in a 54 Gibson J160e.

I think it's hit or miss as to what glue you'll find in Gibson made acoustics from the 50's through the 70's and it may not be all one type used in the same instrument. I started a discussion here on the topic in 2010, I didn't know what it was at the time. Paul Hostetter chimed in on the discussion and enlightened me.

Once apart, the glue can be cleaned off easily by scarping or sanding, water, solvent or heat won't touch it.

Here are the pictures. It does appear to be the yellow, crumbly, bubbly glue. I can tell you that it is very brittle.

The back may well come off in a couple pieces as its badly cracked right down the middle. The top is actually in good shape.


one more


well... there it is. came off pretty easily. 

What a wreck the inside of the box is! It appears as if the kerfing had been glued using a different glue than the bracing.


Hey Randy, as a Gibson nut, I can tell you that the letter Y before the FON# on the neck block means that it is a 1953 production.

Good luck with the project!


Looks like a pretty nice guitar when it's back together, early 50s J-45s are really great sounding. 

Retrorod nailed the date re the letter code, Gibson actually went backwards from Z in those years.

And one other note, notice the spray on the X braces and lateral brace right at the sound hole.  I find that to be very common on Gibsons of this era.  I had a '52 with the same spray on the braces and many 'experts' on vintage instruments claimed 'overspray'.  But I almost expect to see this.

Good luck with the repairs!  Tom


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