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Gibson LG1 belly reset
http://www-.luthiersforum.com/forum/viewtopic.php?f=10137&t=52897		 Page 1 of 1
Author:  jabollig [ Tue Feb 04, 2020 2:40 pm ]
Post subject:  Gibson LG1 belly reset
I have a ‘63 Gibson LG1 in the shop that came in for a new bridge (among other things) as the previous replacement bridge had split in half. However, before I can put a new bridge on, I need to reduce the belly. The problem is that the bridge plate underneath has not only been capped in a previous repair, but the original spruce plate extends quite a bit past the length of the bridge on both sides. I assume I would remove the cap before attempting to do anything with the actual plate...but after I would do that, I’m stuck on where to go next. The aluminum cauls I have that I could heat and use to soften the glue aren’t big enough to cover the entire plate, and if they were, I don’t think I could even get them inside the body (especially when hot). Or would it even matter that they don’t cover the whole plate but only softened the glue where the belly is most prominent?

Any advice is greatly appreciated!! Thanks!

https://imgur.com/a/YEQtSTm
Author:  jfmckenna [ Tue Feb 04, 2020 4:57 pm ]
Post subject:  Re: Gibson LG1 belly reset
If you are talking about a set up like the Thompson Belly Reducer then I would think you need to have something that covers the whole patch. Because the way it works is it softens the glue over the whole bridge patch and as the clamping pressure is applied the patch moves into it's new shape and when the glue re-solidifies it maintains that shape. If you only did the middle the then the edges of the plate would stay fast in position.

Could you make it in two pieces to get it through the sound hole?
Author:  DanKirkland [ Tue Feb 04, 2020 10:08 pm ]
Post subject:  Re: Gibson LG1 belly reset
What you're measuring in your picture is not belly that's the radius of the top.

If you want to measure how bad a bridge plate needs to be replaced you need to measure from the tail block to the end of the fingerboard. If there's a pronounced fold in the top right near the back edge of the bridge then the plate needs to be replaced. A slight fold is somewhat normal but a drastic one is not.

Keep in mind Gibson built guitars with a very pronounced top radius. If you try to flatten them to be like a Martin you will never achieve that. I've run across some LGs with a top radius as pronounced as 25. For reference a typical Martin top is built to 41. So an attempt to flatten the top using heat will not work. That's really only a temporary fix and eventually the top just creeps back to where it was previously so I'd advise against it.

How did the previous bridge break in half?
Author:  jabollig [ Tue Feb 04, 2020 11:36 pm ]
Post subject:  Re: Gibson LG1 belly reset
DanKirkland wrote:
What you're measuring in your picture is not belly that's the radius of the top.

If you want to measure how bad a bridge plate needs to be replaced you need to measure from the tail block to the end of the fingerboard. If there's a pronounced fold in the top right near the back edge of the bridge then the plate needs to be replaced. A slight fold is somewhat normal but a drastic one is not.

Keep in mind Gibson built guitars with a very pronounced top radius. If you try to flatten them to be like a Martin you will never achieve that. I've run across some LGs with a top radius as pronounced as 25. For reference a typical Martin top is built to 41. So an attempt to flatten the top using heat will not work. That's really only a temporary fix and eventually the top just creeps back to where it was previously so I'd advise against it.

How did the previous bridge break in half?


I'm not sure how it broke specifically, but I added some more pictures to the link that show the old bridge and where it broke, I guess "in half" isn't the most accurate term here :D ...

I'll go back and remeasure as you mentioned and snap a few pics of the result. Thank you!
Author:  DanKirkland [ Wed Feb 05, 2020 12:01 am ]
Post subject:  Re: Gibson LG1 belly reset
jabollig wrote:

I'm not sure how it broke specifically, but I added some more pictures to the link that show the old bridge and where it broke, I guess "in half" isn't the most accurate term here :D ...

I'll go back and remeasure as you mentioned and snap a few pics of the result. Thank you!


I asked how it broke because that does help to identify the problem in more than a few ways. I could've phrased it a bit differently lol

Looking at your pics again it looks like the first brace right behind the bridge plate is loose in the middle? If it is then that's definitely contributed to the bridge breaking. If you reglue that well then you might just fix your problem.

Whoever added that overlay did you alot of good favors by adding some strength to the plate. What they basically did was add a proper bridge plate on top of the spruce one. The spruce plates in these are a pain to get out so I totally understand why they did that. I'd just leave the plate alone honestly.
Author:  jfmckenna [ Wed Feb 05, 2020 8:47 am ]
Post subject:  Re: Gibson LG1 belly reset
Well that's Gibson's bridge design for ya. The plastic one probably would never have broken but those were awful too. Get a thin spatula and poke around to see if those braces are loose.

In fact seeing the pics now it looks like that one was made with that resorcinol glue which is typically seen with that reddish squeeze out. I would be surprised if the braces were in fact tight. And you may well find that the entire brace will come right off!

If that is the case then you might be able to flatten it more by re-bracing it.
Author:  jabollig [ Wed Feb 05, 2020 12:28 pm ]
Post subject:  Re: Gibson LG1 belly reset
DanKirkland wrote:
What you're measuring in your picture is not belly that's the radius of the top.

If you want to measure how bad a bridge plate needs to be replaced you need to measure from the tail block to the end of the fingerboard. If there's a pronounced fold in the top right near the back edge of the bridge then the plate needs to be replaced. A slight fold is somewhat normal but a drastic one is not.


I added two more pictures from the tail block to fingerboard perspective, which was much more challenging to get a picture of than I thought it would be :P
DanKirkland wrote:
Looking at your pics again it looks like the first brace right behind the bridge plate is loose in the middle? If it is then that's definitely contributed to the bridge breaking. If you reglue that well then you might just fix your problem.

jfmckenna wrote:
Get a thin spatula and poke around to see if those braces are loose.

In fact seeing the pics now it looks like that one was made with that resorcinol glue which is typically seen with that reddish squeeze out. I would be surprised if the braces were in fact tight. And you may well find that the entire brace will come right off!

Both the brace behind the bridge plate and the brace closest to the tail block are loose in the same area, which is about from the B string line to the low E string line. I can get a small spatula the the furthest brace, but the brace by the bridge plate is a real pain with the plate being where it is!

Thank you both for your help!
Author:  jfmckenna [ Wed Feb 05, 2020 2:12 pm ]
Post subject:  Re: Gibson LG1 belly reset
I've definitely seen worse bellying. I would probably heed Dan's advice and don't worry about the bridge plate. But it's hard to make judgement even with good pics. I would also suggest getting that spatula under the braces and tug on it pretty good to see if the whole brace just pops loose. Those old Gibsons seem to come in with loose braces more often then not and that glue gets so brittle over time I would not be surprised if the whole brace just pops off. And in fact that would make it easier to clean up and repair with the extra added ability to flatten the top a bit more.
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