12 strings 70s ibanez concord 684 with bridge issue and need some TLC

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ka_who
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12 strings 70s ibanez concord 684 with bridge issue and need some TLC

Post by ka_who » Thu Nov 12, 2020 6:36 pm

recently I purchased a 12 string Ibanez concord 684 from charity store, I think this is a common issue with them and as most of them the bridge separating from the top, I fixed similar issue in some other guitars following "twoodfrd" videos on youtube and they held up ok so far, this guitar has a bent bridge and I believe the separation caused or at least started because of the bridge started twisting. my question is is it possible to flatten a twisted bridge if it removed and cleaned and what is the chance it developed the same twist again. I don't have any special power tools and never used routers before that's why I prefer to find a way to flatten the bridge and reglue the thing. also, I'm not much a player either and not sure about the fret hight but I think the frets are too low, wondering how pros measure the hight of a frett and when they decide its time to re-fret a guitar?
I think I might get an accurate reading if I press adjason frets and check the highest by filler gauge but I don't know what is the good or bad numbers

Also I think I like to bring the saddle up while maintaining the action of the guitar, don't want to go to that dissociation here, but I'm wondering if anyone can point me towards a good guide for that matter!
Thanks
Al
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seeaxe
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Re: 12 strings 70s ibanez concord 684 with bridge issue and need some TLC

Post by seeaxe » Sun Nov 15, 2020 8:36 am

I had almost an identical guitar, a long time ago. Mine was a Suzuki, but same Hummingbird copy.

my starting point would be ...what are the actual problems with this guitar?
1. Do the frets buzz anywhere?
2. Are they badly worn?

If answers are no and no, learner, leave them frets alone.

In my opinion you want a low fret height with a 12 string as when you fret the octave pairs, if frets are high you have room to press the strings down before hitting the fretboard, then you can/will change the pitch as you play, leading to not good noise.

3. Is the action too high for comfort higher up the neck (you can google recommended string height for 12 strings)
If no, leave the bridge alone unless it actually falls off.
If yes, it is rarely fixable by twiddling those screws either end of the saddle as you are usually too high. See 6 below

4. Has the bridge rotated or is the corner just lifting? Looks from the picture that the back of the bridge is still stuck down. So the corner has come up - so what?? Edit...looked again, it is coming off. See 7

5. Has the top bellied? I.e. big dip in front of the bridge and big bow behind it. If not, leave it alone.

I assume you are aware that 12 strings are usually tuned to C sharp and not E?? Capo on the third to play along with everyone else - after you have finished retuning it for the capo, and retuning again cause you've been playing for 10 mins and again cos its warmed up or because someone switched the aircon on. :) :) Gotta love them though, orchestra in a box.

6. If yes, you have a fairly serious problem and if you like the guitar enough, take it to a luthier and get them to re top it and do a refret if it needs it while you are there. That might sound expensive but consider this. The sound of any guitar is 90 percent due to the top and bracing. Get a new top and you effectively have a brand new, luthier built 12 string.

7. If its just the bridge, and everything else is OK, take it to a luthier who will be able to get the bridge off without destroying the top. Probably easier to just make a new one and glue it back. Not something I would suggest you tackle if you don't know what you're doing as you will probably wreck the top. Is the top ply or solid by the way???

Good luck
Richard

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kiwigeo
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Re: 12 strings 70s ibanez concord 684 with bridge issue and need some TLC

Post by kiwigeo » Sun Nov 15, 2020 11:25 am

The reason the bridge is lifting at rear is a glue joint failure. The bass side has lifted first because string tension is higher on the side of the bridge. Eventually the whole back will lift. This needs fixing before you start playing with the action. As Richard recommends...take the instrument to a luthier. You might get away with getting some glue in and clamping up but its more likely the bridge will need to come off and either refixed or a new bridge made up...depending on state of underside of bridge and how cleanly the bridge comes away from the top.
Martin

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Mark McLean
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Re: 12 strings 70s ibanez concord 684 with bridge issue and need some TLC

Post by Mark McLean » Sun Nov 15, 2020 10:26 pm

Yes, this is the common syndrome seen in cheap old 12-strings. All of that string tension pulls the bridge up, and also usually deforms the top as Richard described in his point #5, and also gradually pulls the neck angle forward. Eventually those things cause the string action to rise, and that makes a 12-string really hard to play. I think this is what you are describing when you say that the frets are too low. More likely is that the frets are fine, but the strings are too high. Measure the gap between the top of the 12th fret and the bottom of the bass string. A good action would be a gap of about 2.5mm. Anything above 3mm is too high to comfortably play. I bet yours is much higher.

When this happens the easiest remedy is to lower the saddle by filing some material off the bottom - or in those old Ibanez axes you can lower the saddle using the screws in the bridge. That will make it better for a while, but the action will gradually rise further. Most of these old guitars have had the saddle adjusted so many times that it is down to nearly nothing - so low that there is almost no break angle where the strings pass over it (which robs it of a lot of sound and tone) - and the action is still too high. At this point the only remedy is a neck reset, which is major surgery. The final insult is when the glue joint holding the bridge to the top fails (as Martin said), so it starts to lift off. Most pawn shops have one of these old 12-strings, usually a Sigma, Ibanez or Yamaha, showing all of the classic symptoms (and missing one bridge pin, with it replaced by an odd one, or sometimes a golf tee). I am sorry to say that most of these old axes are essentially beyond redemption, unless you are willing to get a lot of work done. But if yours still has some saddle height to play with, and if the top is not deformed, it might be worth a shot. Regluing a bridge is a relatively simple job if it is otherwise OK.

ka_who
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Re: 12 strings 70s ibanez concord 684 with bridge issue and need some TLC

Post by ka_who » Thu Nov 19, 2020 2:35 am

Hi guys, thank you for your advice, unfortunately, I got impatient and went ahead with my distractive idea today before checking the post!!! :x I thought this post was forgotten or disappeared somehow!!! so I did a couple of unrecommended things today and came to the website to delete the post and ask new questions!!!
well to answer the Seeaxe questions, no honestly wasn't much wrong with the guitar just worn frets on 1-2 and 3, the action was around 3 ish but ferreting on the top of the neck was somewhat hard especially for me as my left wrist joints and tendons damaged a couple of years ago because of autoimmune disease. anyways, unfortunately, I went ahead and removed the bridge and frets so the cat is out of the bag now! there was evidence of someone trying to remove the bridge before of me which they gave up and I think they used some epoxy glue there.it was a very hard job to remove the bridge but it came off clean after 5 hours of struggle. now I have to refill the damaged top, don't know if the bridge and top contact, play much roal in the sound in this guitar as saddle id sitting directly on the top of the board. thinking to fill the gouged top with some wood dust and super glue. unfortunately, I removed the freets so I have to put new frets as well. I like to know is the bridge clamp is absolutely necessary? I couldn't find any large clamp in hardware stores and the special ones are expensive. If I match the curvature of the top and bridge to a fine tolerance, is the clamping still necessary or can I maybe support the top from inside and add some weight on the top? the worst-case scenario would be lifting of the bridge again yes? or the lifting bridge could twist and lever-action could break the top? also as Seeaxe asked, I think the top is belied a little bit. anyways I did all the things you advise not to do so this is now almost a lost cause so I don't have anything to lose. I'm going for broke.
PS: I realized the truss rood nut was almost stripped and jammed, I managed to remove it but not sure what size bolt it is, can I cut a cross on the top with derimmle and reuse it or its a recipe for disaster?
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seeaxe
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Re: 12 strings 70s ibanez concord 684 with bridge issue and need some TLC

Post by seeaxe » Sat Nov 21, 2020 11:04 am

Hi again

Good close tolerance mating surfaces AND pressure on the glue joint are both required.

If you have some scrap ply lying around you can make a suitable C clamp. You can use wedges or a bolt to apply pressure. Or you can use a bolt through each of those two pearloid markers on the bridge. Replace of fill markers afterwards. A glueing caul matched to the underside of the top will be a plus and allow you to crank up the pressure.

Refret you can do judt take your time. Truss rod is useless if the thread is stripped. Not sure what you can do about that unless you can find an identical one. Good luck.
Richard

ka_who
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Re: 12 strings 70s ibanez concord 684 with bridge issue and need some TLC

Post by ka_who » Sat Nov 21, 2020 10:17 pm

Hey Seeaxe, thanx for the reply, I managed to bend back the wing on the bridge by steaming it inside a small foil pocket and put it under reverse twist overnight. it came back into normal. I glued the top back using hide glue, unfortunately, because I wasn't quick enough, it did not stay glued for long and sides start to lift up the next day, so I removed it and used PVA glue the second time. that was my first time using hide glue and I really liked the properties of it but couldn't use it in this case especially because I needed to screw those through-bolts first. also, my flimsy clamp set up wasn't up to the task.
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the truss rod itself and the bolt are fine, the hex head is striped! I cut a cross on the top of it just in case the allen-key striped again. my question was what weird size it was and if it was possible to find a new one and replace the nut. the inside hole is 5.2mm and outside is 9mm and the length about 40mm.

the re-frets weren't 2 bad, amazingly non of them buzzed after referee but some ends pooping out and I think maybe its because I used hide glue and should use super glue. also maybe because the fret radius wasn't the perfect match. I still can remove the troubled frets and bend them a bit more and glue them back, but they not horribly bad either. I'm happy how they turned out despite it was my1st time.
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once again thanks a lot for advice and your time. I really appreciate you (backwoods), guys helping newbies.

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kiwigeo
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Re: 12 strings 70s ibanez concord 684 with bridge issue and need some TLC

Post by kiwigeo » Sun Nov 22, 2020 4:26 pm

Did you have a caul on the underside of that top while re-gluing the bridge?
Martin

ka_who
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Re: 12 strings 70s ibanez concord 684 with bridge issue and need some TLC

Post by ka_who » Sun Nov 22, 2020 7:25 pm

Hi, thanks for your reply,
I used an 8mm thick and very tough peace of hide plus some corck. the crock end up glueing to the top and took me 1 hour and so to slowly sand it back to nothing and removing the peace from the body wasn't fun at all. 1thing I dismiss when I build that clamp was the bearing at the screwing part which I learned was almost as important as the rest of the clamp!
wondering if its okay to tune the guitar now? the glue was applied about 24H ago, can I tension the strings now or it should cure longer?
thanks

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