Originally Posted by
Simon Barden
It's very hard to say whether the guitar can be made playable without having it in one's own hands.
First off I'd say go easy on the boiled linseed oil. Yes, a lot of people do use it for oiling fretboards, but for them, it's a case of wiping it on, leaving it for a few seconds and then wiping off the excess. Boiled linseed oil makes up a large proportion of TruOil, and is a glossy wood finish in its own right. Put too much on and you'll end up with a lacquered fingerboard. I'd stop putting it on now.
Alternatives are lemon oil or mineral oil (chopping board oil). These are proper oils, and just stop the fretboard from drying out.
I'd have scraped the fretboard first with a single sided razor blade. This is very good for removing the worst of fingerboard gunk and smoothing out the board.
The serial number says it was made in January 1991 at the FujiGen Gakki factory, Japan.
I've just repaired an 80's Yamaha 12-string that also had a very high action, and got it to be a really low action and easy playing guitar. It took a bit of work but the basic guitar sound.
Two things generally happen on 12-strings over time.
1) The top 'bellies' up, so instead of having the top almost flat as when originally built, there is now a pronounced arch to it and the bridge now sits 2-3mm higher than it should do. The bridge may also be angling forwards.
2) The internal neck block is squashed over time under the string tension, so the neck angle changes and the neck points down towards the body instead of at the bridge.
And of course you can get a combination of 1 and 2.
The Yamaha 12-string's neck angle was fine, but the top was bellying a bit and the saddle was high off the top.
I cured the bellying by fitting a JLD Bridge Doctor (screw-mount version). This works remarkably well at keeping the top flat. But the pin-mount version may be better if you haven't got enough space behind the bridge pins to drill a mounting hole. It all depends on the bridge design, though I think you could just about do it on the Ibanez.
The bridge block was quite chunky, but the saddle was only poking out of the slot by 2mm, so there was no way to simply lower the saddle itself without having zero break angle for the strings. So I took about 2mm off the height of the bridge block (known as a 'bridge shave') so I could take off 2mm from the bottom of the saddle.
I just taped up around the bridge, marked on how much I wanted to take off and then used an electric sander to remove the wood (other methods to do this are available, though I found it very controllable). Then some hand sanding with finer grits to get it level and smooth, and in this case painting it black as before, though you can just finish with linseed oil or lemon/mineral oil.
The limiting factor to doing this is the depth of the existing saddle slot. You'll want at least 50% of the saddle sitting in the slot, and it can't be too shallow or the saddle will angle-over regardless. I was lucky in that the 12-string was an electro-acoustic, and had a really tall piezo element in a metal enclosure sitting under it. I swapped this for a much lower profile piezo element, which gave me my extra slot depth.
If the slot isn't that deep to start with, then you'll have to rout it deeper, which required a very good routing jig and using a Dremel as a router rather than a standard router as you'll need a very thin router bit and a small router footprint. Lots of YouTube videos on this, but start with StewMac. But you don't want to go any lower than just above the top of top itself, so measuring with callipers is important here to work out just how far you can go.
My first attempt to make up a jig ended up with a very wonky line in my template, so I gave up and used the lower piezo element trick (as well as removing a few plastic packing pieces in the slot).
But if the neck is pointing down below the bridge, it is really a lot of hard work to remedy and the neck needs to come off and be reset (with probably some extra strengthening of the neck block). So before doing anything else, you need to use a notched straight edge and the truss rod to get the neck flat, then run a straight edge along the neck to see where it hits the bridge (a 600mm steel rule is ideal for this as you don't need to remove the nut as you would with a 1m rule).
From your pictures, it looks like the last few frets slope down a bit, so ignore those (as they are beyond the neck join so pretty much unplayable), and get the main part of the fretboard level.
Note that a neck reset is a luthier job (not something I'd like to attempt), will take a fair amount of time, and time is money. So it's almost certainly going to cost more than the guitar is currently worth in that condition, and probably as much as it is worth when fixed.
If it looks like the top has bellied, you need to be able to envisage where the top of the saddle would sit if you made the mitigating measures described above and you were able to lower the saddle height. If it's still hitting below the top of the 'virtual' saddle, then you are never going to get a good action over all the neck and its always going to be hard to play. Probably best to either walk away from it or set it up using the truss rod and cutting the nut slots, so that its playable up to say the 5th fret, even if this means setting it up with some back-bow.
If it's hitting level with the top of the virtual saddle, then all is good and you won't need to lower the saddle by so much, and probably just the Bridge Doctor will do it, as well as some truss rod adjustment and cutting the nut slots.
If you are unsure about the above, take some more photos from the side showing the top and any bulge (which will be far less with no strings on) and where a straight-edge hits the bridge after the neck is straightened.
And finally, yes, you need a proper acoustic 12-string set of strings, not electric guitar strings. 10s are normally the lowest gauge strings they do for 12-strings and I'd get those, to minimise string tension.