Top belly and Bridge Tilt Forward

pickitPaul · #1 08-11-2018, 07:38 PM

I have a 1970 Japanese built Starfield Dove copy, all laminate. The top has a belly in the center, and bridge is tilting forward a bit. I had local luthier look at the bracing, and the main X treble side needed glued down, and the bridge was clamped & glued at the back end where it pulled up some.

My questions are, now that brace is clamped / glued, will the laminated top just stay the same with the belly? Is this a good job for a bridge dr., will it flatten the bridge out?

The neck is good, straight and no buzzing, action is good I adjusted it to my liking. It needs a new saddle - this adj. bridge has a slot, and I have a tusq compensated saddle that I took out of my old Tacoma acoustic. I can sand it down to fit the bridge slot, as it has now plastic that I can bend.

Guitar does sound very good, it has a resonance to the tone that I like, suprising for a laminated top / sides / back.

Should I try the bridge dr., or just leave it alone and see if it stays stable this way? Here are some pics of the bridge & belly, more of guitar to just see what it looks like. I strung it with light .12 Martin Monel - probably should go with .11 or .115

mirwa · #2 08-11-2018, 10:01 PM

First bridge doctor is not a doctor for your guitar, it’s a crappy device that ruins the sound of your guitar and IMO ruins your guitar.

All bridges rotate under tension, if they do not rotate in any way, then the guitar will be a dead sounding instrument as it has been over braced and possibly too thick of a top has been used.

A top that has too much belly happening (I don’t think yours has from the photos), but it can be steamed flat again after a bridge has been removed.

Once the bridge is refitted, you are good to go.

Any competent luthier can do this for you. In my locality I charge $120 fo this service, so this should give you a good guide to where you are located.

Steve

mirwa · #3 08-11-2018, 10:05 PM

Example.

Bridge removed top still deformed

Top steamed and flat clamped

Bridge refitted and tuned to pitch, normal bridge rotation, no bellying of the top

Steve

pickitPaul · #4 08-11-2018, 10:49 PM

Thanks for your response, Steve. I wanted to show 2 more pics that has better light.

I will stay away from the Bridge Dr., and now that the bridge & X brace arm have been glued, I will just live with the belly, and watch if it gets worse, keep light strings on it. I often have it in open tuning G or D, or keep 1/2 to 1 step below if I want near standard tuning.

mirwa · #5 08-12-2018, 12:15 AM

Those picture are not flattering, next time you have some work done on it, hit the luthier up to fix that at the same time by clamping and steaming / heat

Steve

pickitPaul · #6 08-12-2018, 08:06 AM

I'd have to remove the bridge to seam it or can it be steamed and clamp with bridge on to remove the bulge in top?

The guy who reglued it thought the front of the bridge (which was still attached tightly) could pull up with wood fibers. So he just injected tight bond under the pulled up front end & clamped it for 2 days, and a loose brace.
Looks like a visit back to him (or maybe not) ?

mirwa · #7 08-22-2018, 06:49 AM

Sorry never noticed reply, yes you need to remove the bridge to steam the top flat.

Steve

redir · #8 08-22-2018, 07:16 AM

If you like the tone and the action is good then just ignore the bellying. Gluing the brace back in place was the important thing. I agree with Steve that the Bridge Doctors are no good for guitars but on cheap guitars like that as a last ditch effort I would use one. But that's only to make it playable again. Yours is playable so leave it at that.

Alan Carruth · #9 08-22-2018, 10:55 AM

Wood 'cold creeps': when bent in a particular direction over a long period of time it takes a set. This can settle in to something like three times the short term deflection that you see under the same load, and maybe even more. It's the reason we use truss rods: they provide a countervailing load to to keep the neck from curving upward over time.

The 'Bridge Doctor' is, in a sense, a 'truss rod' for the top. It adds weight where you don't want it, and may otherwise restrict the motion of the top, so it changes the sound. Whether it's 'better' or 'worse' is a judgement call that depends on a whole lot of things. Fortunately, if you don't like it, you can pull the thing out.

IMO, that belly in the top is nature's way of telling you that the top wants to be bellied under the load. If you steam it flat and don't do something to reinforce it, it will just belly up again. If it's not getting worse too quickly, sounds OK, and the bridge can be persuaded to stay down, you could just live with it.

nickv6 · #10 08-22-2018, 11:06 AM

I've used a bridge doctor in a very good guitar which had bellied. It completely revived the guitar, improved bass response massively. I can't think why it worked and I only did it as a last ditch effort to save the guitar. Guitar is now completely stable several years later.
Nick

Edgar Poe · #11 08-22-2018, 11:28 AM

Quote:

Originally Posted by mirwa

Example.

Bridge removed top still deformed

Top steamed and flat clamped

Bridge refitted and tuned to pitch, normal bridge rotation, no bellying of the top

Steve

Do you have an after photo of the straight edge on the soundboard ?

Ed

mirwa · #12 08-22-2018, 06:04 PM

Quote:

Originally Posted by Edgar Poe

Do you have an after photo of the straight edge on the soundboard ?
Ed

Not on this one ed, this came from one of my tutes on how to remove and refit a bridge, the flattening of the top was an inconsequential part of the job, I can link you to the tute in a Private message if you want to read the whole job.

Steve

BillRomansky · #13 08-25-2018, 05:01 PM

Before any repairs, loosen strings and tension rod, lay the guitar in a case flat, put a small bowl of water in the bottom of the guitar, and leave it for a week or more with the case closed to hydrate the under bridge area. The belly and forward tilt may simply disappear, or improve to not an issue. Be careful, I did this in a Martin HD-28 and my granddaughter bumped into it, loosening the back binding with the soaking.

mirwa · #14 08-26-2018, 07:20 AM

Quote:

Originally Posted by BillRomansky

Before any repairs, loosen strings and tension rod, lay the guitar in a case flat, put a small bowl of water in the bottom of the guitar, and leave it for a week or more with the case closed to hydrate the under bridge area. The belly and forward tilt may simply disappear, or improve to not an issue. Be careful, I did this in a Martin HD-28 and my granddaughter bumped into it, loosening the back binding with the soaking.

Sorry, I so dis-agree with just putting a bowl of water in a guitar, one really needs to know if it’s too wet or too dry and then approach the repair process, which still would not involve putting a bowl of water inside

Steve

BillRomansky · #15 08-26-2018, 07:28 AM

Good point, I’ve been living in the desert for too long. If you’re in Florida with 90% humidity, this is probably a futile exercise. On the other hand, not really much difference between a bowl of water and an insertable humidifier, is there? So put a well soaked sponge in a bowl in the guitar, which will avoid accidents. My faux pas, check it daily until the belly leaves. This is the first course of action for a seam split as well.

I’m also thinking the cost/benefit ratio on a ply top. Me, I’d hang this guitar on the wall before sinking more than the value of the guitar into a repair.