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Thread: Gibson LGO Plastic Bridge

  1. #1

    Default Gibson LGO Plastic Bridge

    I recently got a 60's Gibson LGO in the shop for a repair. It has a plastic bridge with a fixed saddle (non adjustable). The top has fairly serious bellying though the bridge hasn't pulled loose. Click image for larger version. 

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    The main complaint was that the guitar had bad action and no longer sounded good. I assumed there might be loose braces, but inspecting the inside, I could see all the top braces (ladder) were solid, though bellied. I did see one very loose back brace. This guitar has 4 bolts holding the bridge on from the underside and that there is fairly significant tear out on the pin holes of the bridge plate.

    Click image for larger version. 

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    From the looks of this, I'd assume this is original. My thought would be to remove the plastic bridge, slowly and gently heat and flatten the top using weights, fill the bridge plate holes using a Stew Mac Bridge saver, then replace the plastic bridge with a wooden one. I believe a truss rod adjustment should take of the neck issues. I'd appreciate any thoughts or suggestions from any of you, particularly if you've worked on an LGO.

    I know I had a hard time locating a proper replacement bridge for a project in the past. Does anyone know of a good source for a genuine Gibson reverse belly bridge?

    Thanks!

  2. #2

    Default Re: Gibson LGO Plastic Bridge

    The plastic bridge is original. In time, it will crack and bow even more -- but then again, it has already lasted 50 years without coming off. I did a similar repair recently. My customer would have preferred a new original plastic bridge to keep the guitar original, but I couldn't find one. I'm sure they show up on eBay from time to time, but in what condition? Allparts makes a wooden "belly up" Gibson style bridge that worked fine and made the customer happy. It wasn't an exact reproduction, but very close. The holes on the original plastic bridge are nearer to the bottom of the bridge than the new wooden repro, but the relationship from the holes to the saddle is correct, so if you line up the holes (they can only go in one place, right?), then the intonation should be close. There may be a gap showing on the front edge of the new bridge that was covered by the old bridge, but since it was a bolt-on bridge, it will have finish under there, so no problem. Except it might be a little shiny in that one spot compared to the rest of the top. Anyway, I explained the options to my customer and they were happy with the result. Keep in mind, an LGO is not the greatest sounding Gibson to start with, being ladder-braced and small bodied, boxy sounding, as they say....but anyway the action can be improved, for sure.

  3. #3
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    Default Re: Gibson LGO Plastic Bridge

    I have had LG0s in the shop that sounded great. Ladder bracing has it's own sound, but some like it a lot. Collings are making some very nice ladder braced guitars. Anyway I found that strings on a guitar just like a mandolin make a difference in sound. I like the GHS silk and bronze for a ladder braced guitar. Also a lighter gauge string will work better. I do like to raise the gauge on the low E some for a better sound on most guitars, especially those with lighter strings. I also like to remove the finish under the bridge so it can glue on, it will help with the belly bow, last longer and I feel sound better.
    THE WORLD IS A BETTER PLACE JUST FOR YOUR SMILE!

  4. #4
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    Default Re: Gibson LGO Plastic Bridge

    Click image for larger version. 

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ID:	162549I had one that belonged to a close friend come in with some of the same issues ++++! My friend, a house carpenter had tried to "correct" the belly by glueing [with construction adhesive] a 2.5" x 3/8" thick x full width of the lower bought chunk of plywood behind the ladder brace under the bridge..... Needless to say.. didn't correct the problem and "no saving that top".

    The guitar had sentimental value to him and he decided that he wanted it replaced with an X braced, Spruce top...... Not cost effective vs the value before AND AFTER of the guitar..... but for a friend???? What the heck and my deck did need some work.

  5. #5
    Teacher, luthier
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    Default Re: Gibson LGO Plastic Bridge

    On these instruments, I make a new bridge out of rosewood or ebony, reinforce or plug the bridge plate, and repair any loose braces. I prefer to make a slightly oversize bridge with more wood behind the pin holes to increase the gluing surface and add some strength to the weak design. It's not hard to make a bridge with a coping saw, drill press, and a belt sander. I clamp a fence on my drill press, make a jig to slide the bridge along the fence at the correct angle, and chuck in a router bit to cut the saddle slot.

    Reshaping the top without replacing the bridge plate and removing and regluing the two braces surrounding it sounds like an exercise in futility to me-- the top will revert to its current shape sooner or later, and the difficulty and cost of such a repair is not worth it on a guitar of this value.

    If the action is bad because the neck angle has changed and it needs a reset, you might want to advise your customer that the price of the repair can exceed the value of the guitar.

  6. #6

    Default Re: Gibson LGO Plastic Bridge

    Thanks for the excellent comments!

    I went ahead and removed the bridge using 1/4"socket wrench, a bit clumsy, but effective. As Pops1 had suggested, the bridge was not glued on, only screwed on and the finish under the bridge had not been removed, something I'll remedy before I put on a new bridge.

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    Jeff, your comment about the bridge continuing to shrink over time was quite astute. when I removed the bridge, I noticed a significant lessoning of the bellying suggesting that the shrinking bridge played at least some part in that problem. Upon closer inspection, I also noticed something I'd seen in a previous repair of a 1950s Gibson 160 E; the top had been compromised by the 4 additional holes cut for the screws and had cracked between the A through B string holes. Those 2 factors could explain why the guitar was bellying with no loose braces.

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    My plan at this point is to gently heat and flatten the top, then glue the damage and fill in the screw holes with the bridge saver. I've had good luck doing this, but it takes time and care. The idea is to gently heat the top so that the glue holding the braces can be softened enough to slightly shift position. I expect about 1 week of gently heating once a day, then either clamping or weighing the top down will do it. I'll post pics as I go and we can see if it works or not.

    I do have one of the Allparts reverse belly bridges which I had purchased for the previously mentioned repair but didn't use. It should do the job, but as suggested, is not a perfect match. There will be a line from the "ghost" of the original bridge in front of the reverse belly. It does have a bit more wood behind the pin holes as rcc56 suggested, though.

    At some point, I'm going to need to bite the bullet and buy the tools necessary to make my own bridges. I have a terrible time getting proper replacement bridges, even when I pay for CAD and custom made bridges based on the originals. rcc56, any chance you could post a pic of the jig you mentioned? I'd love to see how that works.

  7. #7
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    Default Re: Gibson LGO Plastic Bridge

    Sorry, I'm computer dumb and have no camera, not even a smart phone.

    It's just a 3" x 18" rectangular piece of plywood or 1 inch board, with rails tacked to it for the flat front or back of the bridge and one side of the bridge to lean against. The rails form a 90 degree angle which fits the corner of the bridge. The rails are set at an angle to the edge of the board so when you slide it along the drill press table with the fence, the bit cuts the slot at the proper angle.

    The way that it works is that the jig holds the bridge at an angle so the saddle slot will be parallel to the edge of the jig base. The bridge is secured to the jig with a couple of flat head wood screws that go through 2 of the string holes. Pretty crude and a trifle clumsy, but it works. One day I'll build a better one.

    If I can remember, I'll try to get a visitor to take a couple of shots of the jig and post it or email it to you. It sounds complicated when you try to describe it, but it's really very simple if you see it-- just a rectangular base and a couple of rails.

    If you lay a dollar bill on a piece of paper so that the bill sits at an angle to the edge of the paper, that's how the jig works.
    Last edited by rcc56; Nov-26-2017 at 2:42pm.

  8. #8
    Moderator MikeEdgerton's Avatar
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    Default Re: Gibson LGO Plastic Bridge

    I've been replacing those plastic bridges for years. They used to make a very slightly over sized wooden bridge that looked the same. You needs to remove the finish where the bridge will be glued and glue as you would on any bridge replacement. By the way, your jig sounds a whole lot like the one I built years ago.
    "Bargain instruments are no bargains if you can't play them". These are the words of J. Garber.

  9. #9

    Default Re: Gibson LGO Plastic Bridge

    Further inspection inside shows that the bridge plate is also compromised to the point where it makes more sense to replace it than repair it. For a ladder braced Gibson, this isn't too hard. I did the same thing on the 160 E I've referred to before. I've currently got wet paper towels on the bridge plate to add moisture and in a day or so, I'll apply gentle heat. Last time this worked like a dream. The bridge plate looks like spruce (as was the 160 E). I replaced that one with a slight larger maple one that seemed to work quite well. I'll probably do that as well here.

  10. #10
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    Default Re: Gibson LGO Plastic Bridge

    Every time I have replaced a spruce bridge plate with maple on a ladder braced guitar the guitar sounded better and seemed less likely to bow as quickly in the future.
    THE WORLD IS A BETTER PLACE JUST FOR YOUR SMILE!

  11. #11
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    Default Re: Gibson LGO Plastic Bridge

    Hard maple makes a really good bridge plate. Spruce is awful. I've taken bridge plates out of late 40's Gibsons that looked like they were made from old rotten warehouse pallets [and they very well may have been!].

    If you're going to replace the bridge plate, you might want to see if the two braces surrounding it can be removed easily. If so, then they can be reshaped and reglued and the top can be more easily and reliably flattened. A lot of work, though.

    I don't like to pull bridge plates!! But I pull them when I have to. It's easier to pull one from an old Gibson than it is to pull an oversize one out of a Martin. The last Martin I did almost made a quitter out of me-- there were problems.

  12. #12

    Default Re: Gibson LGO Plastic Bridge

    Yes, bridge plates can be a real issue. Fortunately I got this one out with no issues. As I suspected, it was seriously compromised. As soon as I got out, almost all if the bellying disappeared.

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    The length of this is longer than usual bridge plate stock but I had bought a maple fingerboard blank and cut that down for a previous repair so I'll use the rest of that and thin it to match the original.

  13. #13
    Registered User jim simpson's Avatar
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    Default Re: Gibson LGO Plastic Bridge

    Here's one from a few years back, I plugged the screw holes, removed the finish, and glued a new bridge onto mine. I didn't have to change the bridge plate fortunately. The pickguard was missing so I cut a new one with self-stick backing to replicate the original shape. I never liked the idea of a screw holding a pickguard down.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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    Cabin Fever String Band, Bill Gorby and the Musical Mercenaries

  14. #14

    Default Re: Gibson LGO Plastic Bridge

    Nice work. Did you cut that bridge or is it a repro?

    I got the new bridge plate thinned down to match the original spruce one (.156") and filled in all the screw holes with Mahogany plugs. The new bridge plate is about 3/16" wider than the original and about 1/8" longer. I just glued it in with fish glue and set it a bit farther back than the original.

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  15. #15
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    Default Re: Gibson LGO Plastic Bridge

    I think you and your customer will like the sound of the maple bridge plate. I have seen it improve several in the past.
    THE WORLD IS A BETTER PLACE JUST FOR YOUR SMILE!

  16. #16
    Registered User jim simpson's Avatar
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    Default Re: Gibson LGO Plastic Bridge

    "Nice work. Did you cut that bridge or is it a repro?"

    Thanks, I believe it was a repro, I had to do a little shaping.
    Best with your project.
    Cabin Fever String Band, Bill Gorby and the Musical Mercenaries

  17. #17

    Default Re: Gibson LGO Plastic Bridge

    Here's the rest of the the story of the LG0. After getting the bridge plate glued on, I adjusted the replacement reverse belly bridge to fit the guitar and glued it on with fish glue. I had this one from a previous job. I think it was an Allparts bridge.

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    Next, I re-glued two loose back braces and cut a bone saddle blank.

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    I compensated the saddle and strung it up to check out the action. The top had flattened out and gone back to it's original profile (slightly radiused) and the neck seemed to pass the ruler test and didn't need a neck re-set but when I tuned it up, the action was quite high. I thinned the bridge and lowered the saddle and adjusted the truss rod. It all helped, but there was still something wrong with the neck angle. There was a slight bow where the neck joined the body. Upon very close inspection, I found that the fingerboard extension was loose from the top allowing the neck to push forward just enough to throw everything off.

    I cleaned out the dried glue, heated the extension and injected hot hide glue beneath the fingerboard. I also filled the old pick guard screw holes with mahogany plugs overlaid with mahogany veneer to match the grain pattern

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    Once the extension was glued down, I had a flat neck again. A few minor set up tweaks, a couple finish touch ups and it was all done.

    The action is quite comfortable, intonation is excellent all the way up the neck. The tone was quite thin and bright at first, but the more I played it, the more it opened up and began to have a more classic Mahogany sound. I returned the guitar to a very happy owner this afternoon.

    Thanks to all the forum members for the comments and advice!

    In my haste to get the guitar returned, I forgot to get an "after" shot, but the owner has promised to send one and I'll post it when I get it.

  18. #18

    Default Re: Gibson LGO Plastic Bridge

    Here's a picture of the completed guitar.

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  19. #19
    Mando accumulator allenhopkins's Avatar
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    Default Re: Gibson LGO Plastic Bridge

    More work on an LG-0 than I'd consider economically justified, but a great job! We get attached to certain instruments, and want to get them repaired and restored even though we'll never "get the repair cost out of them" if we sell or trade them. I should know; I have many more repair dollars into, say, my Regal taropatch, than it's worth -- to anyone other than me.

    Congrats on a thorough job!
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  20. #20

    Default Re: Gibson LGO Plastic Bridge

    Thanks, Allen. At this point, it's still about the joy of bringing an instrument back to life and honing my skills, but yes, the hours were significant on this!

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  22. #21
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    Default Re: Gibson LGO Plastic Bridge

    Someone I know brought one into the shop that he got for a couple hundred, it sounded amazing. Ladder braced and wow. This was a few years ago and he is still loving that guitar. Looked like crap, sounded like gold.
    THE WORLD IS A BETTER PLACE JUST FOR YOUR SMILE!

  23. #22
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    Default Re: Gibson LGO Plastic Bridge

    I don't want to worry you, but instead give you a heads up. I have not used fish glue, so this is not from personal experience: but I have heard quite a few reports of fish glue giving way after an extended period of time, often in humid climates. Hot hide glue or Titebond I may be the better choices, especially for high stress joints such as bridges.

    The open time of hot hide glue can be extended by warming the parts with a hair dryer, or by adding 5% to 10% urea [by weight] to the dry glue before adding the water. I got a pound of urea from the local artist's supply for just a few bucks. It's probably more than I'll ever use, so if you want to experiment with it, pm me and I'll send you some.

  24. #23
    Adrian Minarovic
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    Default Re: Gibson LGO Plastic Bridge

    My recommended would be plain old HHG, then Fish, then Titebond and only after that HHG with urea, but I would likely not recommend anything other than clean HHG for steel string guitar bridge.
    Fish glue is more elastic than hide but it has worked in natural composite bows (imagine the stresses - and they are normally not unstrung unless they are going to be stored for long time) for centuries so there is no big problem with humidity (unless you soak the guitar), Titebond has tendency to creep at elevated temperatures and HHG with urea (especially when theres too much of it - like the liquid HG in bottles) has tendency to suck moisture from air and can be unrelaible for stressed joint...
    Adrian

  25. #24

    Default Re: Gibson LGO Plastic Bridge

    Wow, very interesting about fish glue. I had read that it was as good as HHG (which I use more than anything else) but didn't "slip" as much... a good property when seating a bridge since even the slightest movement can cause problems. In this case, I was able to anchor the bridge with plastic pins so I didn't need to use that type of glue but I had been led to believe it would be a good alternative. I'd love to hear from other folks about their experiences.

    I've definitely had Tite bond creep on some serious repairs in the past but I did use that on the internal back braces since I had a hard time getting glue into the farthest cracks and that gave me the longest working time. I did remove one brace and completely clean it before re-using. The other I simply scraped out the old glue with a seated palette knife.

  26. #25
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    Default Re: Gibson LGO Plastic Bridge

    A good way to keep a bridge from moving while it is being clamped is to drill two tiny holes through the saddle slot. I use a couple of short, skinny brads or nails as locating pins-- they go through the holes in the saddle slot, and I pull them out after the glue is dry. I use a similar technique when regluing a fingerboard. Usually, I pull 2 or 3 frets, save and mark them, drill 2 holes through each vacant fret slot, and replace the frets when the glue is cured.

    Hot hide glue is my glue of choice for bridges on most older instruments. Sometimes I use Titebond I on modern bridges or where the wood is badly oxidized and I don't want to scrape too much off. Hide glue doesn't work well on dirty or oxidized surfaces, or on joints that are not a good, tight fit. If there's a lot of wood missing, I graft in new wood no matter what glue I'm using.

    I've been experimenting with HHG with urea on lower stress repairs where I need more open time, but I wouldn't use it for a bridge or neck. My mixture is not liquid at room temperature-- I heat it before using. I increase the drying time whenever I use it.

    So far, it's been 2 years since my earliest use of glue with urea, and I've had no returns. I do live in a high humidity area. I don't use it much, though.

    I'm going to have to hear many more positive reports on fish glue before I use it. Most of what I've heard has not been so good-- maybe it's the user, maybe it's the glue-- I don't know; but I'm going to stick to what has worked well for me in the past for the time being.

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