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This guitar came into my shop yesterday. Initially for a new nut and saddle, fret dress and setup. On the surface it's one of thousands of Ibanez Gibson knockoffs. But this one came right at the "lawsuit" and is apparently one of only around 50 made of this model (Concord 755) before production shut down. So somewhat interesting in terms of history, if not aesthetically appealing.



The owner is the original owner who bought it new for $100 about 40+ years ago. Got a deal due to a chip in the soundboard finish. It's his baby and favorite acoustic, so he wants it to continue to live and make music.

He says it plays great and has a low action. This seems a bit surprising given my inspection, and that he says it has never been worked on. Immediately obvious was a severe hump and dip in the soundboard from the bridge. Somehow the hump and dip must have equalized out to keep the saddle at about the same height.




It's got a definite twist in the neck that I'm not going to do anything with.



But the main issue that I need to tackle is the bridge, which is separating from the top. I think the only reason it hasn't pulled off completely is the bolt on the back edge. I can get a feeler gage almost 0.3" under the back side. The gap will not close with clamping pressure.



So, the question for all of you is the best approach to this. Is anyone familiar with the glue they used and how easy it will be to pull the bridge? Then, new bridge or use the old one? The current one is actually quite thin, with a shallow saddle slot that had a relatively low sadddle (again I'm not sure that this guitar has not been worked on). But I'm hesitant to make it any thicker, as that will change the string height. Another issue is that the truss rod is locked in place. Apparently has never been adjusted, so even doing a fret dress and leveling is suspect since I can't straiten the neck (currently slightly back bowed without string tension.

My thought is to make the new nut and saddle (both the original plastic ones are cracked) and string it up to tension to see where the neck and string height settle in. Then see how much bridge/saddle height I have to work with. Then pull the bridge. If it comes of cleanly and I can get it to lie flat once everything is cleaned up, then reattach it. If not, then make a new bridge and attach. The setup will then pretty much come down to nut and saddle height only, since I can't adjust the truss rod.

Sound reasonable? Am I missing anything?

Thanks!

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Tony Thatcher
Bozeman, Montana

Sounds reasonable. Really need to have string tension to see where the action and neck settle in. You could make a temporary nut and saddle out of scrap ebony for this experiment.

I am currently working on a '68 Gibson J-45 that has a twisted neck that is a lot worse than that one. It is turning out to be an interesting project.

Tony, before you take the bridge off, check the neck angle carefully. The old straightedge on the fretboard pointing to the bridge trick works pretty well. I'm going to guess that your guitar will need a neck reset along with the other work, but decide on that before you pop the bridge.

As far as regluing the bridge, that is probably the second most common structural repair that I do (cracks being the first). One of two things will happen, either you apply a little head and work your pallet knife under the bridge and it separates at the glue line or it separates in the top wood. Its been my limited experience that cheap modern guitars separate at the glue line because the manufacture didn't remove enough finish and tried to glue the bridge to the finished top - these are pretty easy to fix once the finish is removed.

The second case where there is some wood that stays with the bridge can be harder to fix - and I don't know of any way to guess whether this will be a problem or not. I tape around the bridge to protect the top, put a little heat blanket on it (a clothes iron will work but be careful you don't touch the top) and I just slowly work the pallet knife back and forth, if you can come in from one wing it seems to work the best. Clean off all the old glue, build yourself some sort of cauls and clamp it back up.

We have had several discussions about bridge clamping cauls - I made these out of UHMW so glue doesn't stick to them. The screw holes are adjustable to fit different pin hole spacing and the bolts are recessed so the caul sits flat against the bridge plate. I make some sort of caul that sits on top of the bridge and use the bolts to align everything and apply three clamps.







I usually use Titebond for regluing bridges because I don't feel I have the experience with HHG to do a good job. On a couple of vintage instruments I forced myself to use hide glue because I knew it was "correct" but most of the time if I clean the old glue completely I'm happy with Titebond.

I guess the only reason I would consider making a new bridge would be if that one had issues (cracks) or was simply the wrong height to work with your neck angle.

The other question thru all of this is how much relief do you have and do you want to try to correct it. We've had a couple of other discussions about guitars without adjustable truss rods and how to deal with relief and/or humps. I just finished working on a 1970's BC Rich acoustic with a non adjustable rod and the relief was a perfect 0.008 after all these years. Amazingly, the neck angle was also perfect in spite of the fact that the guitar has a Spanish heel neck joint.

Good luck with yours

I'm going to add a second thought. I have a policy that before I start any work on a guitar (unless this is impossible) I try to measure everything I can. In your case that would mean putting the original nut and saddle in (unless they are simply not usable) and stringing it up. Measure neck angle, string height off the top, relief and nut and action heights. Is that twist to the neck going to be a problem (might be time to compensate for it). What is the conditions of the frets (I like them to be perfect before putting a lot of time into something else).

My little rule of thumb is that I want the guitar properly humidified, structurally OK, and with good geometry before I start the mundane work of "setting it up". And I like to take all of those measurements before I start because then its too late.

Thanks, all. Yup, lots of measurements. Unfortunately the old nut and saddle are in pieces and I wasn't able to see it strung up. I might be able to piece them together, but will likely have to take the temporary approach. I've got several scrap nuts and saddles that could be used. Might even have some old strings I could re-purpose.

And it might be time to make one of those fancy clamping cauls. I usually cover my plywood ones with packing tape so they won't stick.

I'll keep you posted once I get the go ahead from the client.

-T

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Tony Thatcher
Bozeman, Montana