#1
Well I have what must be a really basic question I feel I ought to be able to figure out for myself but my brain won't do it... :-/

I've just bought a rather nice old Fender F-55-12 string on ebay for far too much money which was clearly a Big Mistake as now I have had a play around with it, the top is badly bellied and the action is stupidly high. But it sounds so much nicer than my sterile Washburn that rather than hanging it on the wall for decoration or using it for lighting the fire, I'm casting around for ways to make it more playable.

After a bit of research I've just ordered a 'JLD Bridge Doctor' which seems to get good reviews so I hope will take out some of the bellying and lower the action a bit. But as this guitar needs new strings too this is my question, I'm wondering what strings to get...

Light gauge strings seem intuitively the right choice for reducing string tension to be kinder to the warped top, but I'm wondering if a heavier string actually needs less tension due to their higher physical mass. Or does string weight make no difference?

Any thoughts/advice on this from those here who know far more than newbie me would be very much appreciated.

Many thanks,
Mike
#2
Quote by mike512
Well I have what must be a really basic question I feel I ought to be able to figure out for myself but my brain won't do it... :-/

I've just bought a rather nice old Fender F-55-12 string on ebay for far too much money which was clearly a Big Mistake as now I have had a play around with it, the top is badly bellied and the action is stupidly high. But it sounds so much nicer than my sterile Washburn that rather than hanging it on the wall for decoration or using it for lighting the fire, I'm casting around for ways to make it more playable.

After a bit of research I've just ordered a 'JLD Bridge Doctor' which seems to get good reviews so I hope will take out some of the bellying and lower the action a bit. But as this guitar needs new strings too this is my question, I'm wondering what strings to get...

Light gauge strings seem intuitively the right choice for reducing string tension to be kinder to the warped top, but I'm wondering if a heavier string actually needs less tension due to their higher physical mass. Or does string weight make no difference?

Any thoughts/advice on this from those here who know far more than newbie me would be very much appreciated.

Many thanks,
Mike
You need to use "twelve string light" sets. These are .010 to .047.
Plus, you have to tune the guitar D-d standard. The tension on the lights is about 250 Lbs. @ concert pitch. IMHO, too much to guarantee a 12 string's survival for very long.

People that don't follow these guidelines, usually wind up with 12 strings in the condition of the one you just bought. C'est le guerre...

There is an even lighter 12 string acoustic set available @ .009 to .045 : http://www.sweetwater.com/store/detail/EJ41?adpos=1o3&creative=55397720281&device=c&matchtype=&network=g&gclid=Cj0KEQjw4qqrBRDE2K_z7Pbvjo8BEiQA39AImbLWY0TXj0KPvCc9jLiT05dWuQgSlvav4CmZa2KUyH0aApL38P8HAQ

IMHO, these have to sound like crap unless you're plugging in.

In either case, the best 12 strings I've heard, are Guild jumbos, and they ship with .012 to .053, "12 string medium sets". Provisionally, these guitars should be tuned only as high as C# to c# standard. (a minor 3rd down).

I use 12 srtring lights, and tune my guitars to D-d, and capo up to E-e when I play.
#3
I've made a few flying braces of the Bridge Doctor type, and currently have one in my old Gibson. My experience is that they will prevent a top form bellying any further, but won't do much to reduce an existing belly. - I once split a bridge across the pins trying to crank it down with a flying brace, so take take how you use it. You could try pushing the top down by putting a weight (eg a bucket part-filled water) on the bridge for few days with the guitar unstrung, then using the Bridge Doctor to brace it in that position.

Heavier strings have more tension, so you need light ones and/or tune down as CC suggests.

I've wondered about using a tailpiece for some or all the strings on a bellied 12-string to exert some downward pressure on the bridge and thereby reduce belly, but I've never tried it.
Last edited by Tony Done at Jun 1, 2015,
#4
Thanks for your comments Captaincranky and Tony.

I've already taken on board the wisdom of tuning down to D and I've seen it makes a big difference to string tension. I'll have a play around with C# too and apply this to the Washburn I also have to save wrecking that too!

I'll try the bucket of water idea, along with hydrating it over a few weeks along with the bridge brace when it arrives. There's no hurry or much risk as the guitar isn't a lot of use as it is.

It's been a most interesting lesson in the things that go wrong with second hand guitars. Well worth learning this stuff by making mistakes with cheap guitars on ebay before I progress to wanting better quality instruments.

What do people do with unplayable guitars, other than sell them on to unsuspecting fools like me?
#5
Quote by Tony Done
I've made a few flying braces of the Bridge Doctor type, and currently have one in my old Gibson. My experience is that they will prevent a top form bellying any further, but won't do much to reduce an existing belly. - . . . . .


Heavier strings have more tension, so you need light ones and/or tune down as CC suggests.

I've wondered about using a tailpiece for some or all the strings on a bellied 12-string to exert some downward pressure on the bridge and thereby reduce belly, but I've never tried it.


Yes ^ ^ ^ ^

Good advice from both Tony Done and Captaincranky about using lighter strings.

A raised top seems to be the fate of most 12 string guitars - the higher tension exerted by the strings makes it pretty much inevitable. The killer of course is that it reduces the break angle of the strings at the saddle meaning a higher saddle is needed hence a higher action which is the last thing you want with a 12 string. And, alas, using a tailpiece is not going to help that.

What I have done on my 12 string - and I've also done it for a couple of friends - is reduce the thickness of the bridge behind the saddle slot. Basically you mask the top of the guitar with card and masking tape, and sand down the area of the bridge around the pinholes - I used a small electric palm sander. I reduced the thickness by about 5mm then re-bevelled and ramped the pinholes. I compensated for the loss of bridge thickness by gluing another bridge plate under the bridge inside the guitar - I used a piece of 3mm plywood cut to size of existing plate, fixed it in place with wood glue and held in position with a couple of screws fitted through the pinholes, then drilled through each pinhole the next day when the glue had set.

This worked a treat - I was able to reduce the saddle height and achieved a good action.