The Acoustic Guitar Forum  

Go Back   The Acoustic Guitar Forum > General Acoustic Guitar and Amplification Discussion > General Acoustic Guitar Discussion

Reply
 
Thread Tools
  #1  
Old 01-06-2009, 08:01 PM
cameronl cameronl is offline
Registered User
 
Join Date: Aug 2006
Posts: 74
Default Reducing belly bulge

Hey everybody, I have a question about belly bulge on acoustic guitars. I have a Johnson Carolina Series JD-27 dreadnought guitar which isn't too many years old. It has a solid Englemann Spruce top. Anyways, back to my question, Is there any way I can reduce slight belly bulge behind the bridge. The bridge is fine and not lifting whatsoever, so I don't want to mess with that. I understand acoustic guitars, maybe dreadnoughts in particular, experience this over time from the constant pull of medium gauge strings, but how much belly bulge is normal. I understand that you can't expect to get a completely flat top on an acoustic guitar while using medium gauge strings on it over the years. But how much belly bulge is normal and is there a way to reduce it without installing a JLD Bridge System. I don't really want to go that route. Does belly bulge have anything to do with humidity? Is there any way I could add or take out humidity to correct this problem? Or is that not an option? Could someone please shed some light on this for me?
Reply With Quote
  #2  
Old 01-06-2009, 08:06 PM
ayavner's Avatar
ayavner ayavner is offline
Registered User
 
Join Date: Jun 2006
Location: Sydney, NSW OZ
Posts: 2,233
Send a message via AIM to ayavner Send a message via Yahoo to ayavner
Default

i think a pic would be useful. certainly an arch is normal, though barely visible...
__________________
illegitimati non carborundum

http://www.youtube.com/ayavner

2006 Martin OMC Aura (Laurelin)
1998 Martin HD-28 (Telperion)
Epiphone WildKat w p90s and Bigsby!
1997 Rickenbacker 360/12V64

Dearly Departed:
1981 Yamaha FG 335
Alvarez AJ60SC12
Regal RD35 Roundneck dobro
Reply With Quote
  #3  
Old 01-06-2009, 08:22 PM
cameronl cameronl is offline
Registered User
 
Join Date: Aug 2006
Posts: 74
Default

I would put a pic up, but my camera isn't working right now, sorry.
Reply With Quote
  #4  
Old 01-06-2009, 09:59 PM
Sugar Bear Sugar Bear is offline
Registered User
 
Join Date: Dec 2005
Posts: 570
Default

Take a good look at it, and if the highest point of the top is not more than 3/16 inch above the top edge of the sides, don't worry about it.

If it bothers you too much, you could go to a lighter gauge of strings.

If it's more than 3/16 inch, it needs help. Without teaching a class, you could clamp the top to flatten it and install a bigger bridge plate.

But the whole thing is pretty complex, there are a number of considerations to deciding exactly how to proceed in a given case, so if you're a beginner at this sort of thing, you should probably have a luthier do it.

It's tough working through the sound hole, and the alternative is removing the back. And of course, the bridge will have to come off. And so on...

Sugar Bear
Reply With Quote
  #5  
Old 01-06-2009, 10:34 PM
BBWW's Avatar
BBWW BBWW is offline
Charter Member
 
Join Date: Jul 2007
Location: San Francisco Bay Area
Posts: 2,107
Default

Buy an original design Breedlove?

Or a bridge doctor....sorry....but they work.
__________________
http://www.reverbnation.com/jayhowlett

Guitars: I'm really happy to have a few nice ones.
Reply With Quote
  #6  
Old 01-06-2009, 11:13 PM
ljguitar's Avatar
ljguitar ljguitar is offline
Charter Member
 
Join Date: Mar 2005
Location: wyoming
Posts: 30,971
Default

Hi cameronl...
Slight bulges on solid tops are to be expected. In addition, if the top is radiused, then the top has a curvature.

Take a straight edge and lay it across the lower bout near the bridge and see how high the edges are from the bottom of the straight edge on each side - when the gaps are equal you can tell how much radius combined with bulge there is.

All four of my guitars have a radiused top, so even if the tops look perfectly flat, there is still a gap at the edges between the guitar top and the straight edge.
__________________
Larry J

Baby #01
Baby #02
Baby #03
Baby #04
Full-size Full-Scale Baby #4

Larry's songs...

…Just because you've argued till a discussion turns silent doesn't mean you have convinced anyone…

Last edited by ljguitar; 01-06-2009 at 11:20 PM. Reason: corrected my ''English'' (loosely speaking) - I meant it to be English when I typed it...
Reply With Quote
  #7  
Old 01-06-2009, 11:24 PM
rcemech rcemech is offline
Registered User
 
Join Date: Nov 2005
Location: Florida
Posts: 664
Default

Could be that mediums are too much for that guitar. Take a ruler and lay it perpendicular to the fret board so that it passes the sound hole and the end sticks past the bridge. If there is a depression or trough under the ruler and a bulge behind the bridge then you have a problem with the bracing or bridge plate and the medium strings are too much for the guitar. If this is the case then it will look like the bridge is tilted forward towards the soundhole. Also I would get a dentists mirror and check and make sure that the braces are not loose or coming unglued. The bulging can affect the intonation and action on the guitar and if a brace is loose then it could ultimately be a warning sign of impending implosion, but I have seen a bunch of older guitars that have lived with bulges (older guitarists too). It ultimately is something you should get fixed by a luthier unless you are supremely confident in your woodworking abilities.

Also, over humidity can cause bulging. Silica packs and some other products can remove the humidity over time if you keep the guitar in the case with them, but be warned you can go too far the other way too.

The bridge doctor can correct the bulge, but who knows what will happen to the tone of the guitar. My brother used one on his guitar and it worked. I cant speak for the tone because he plays so softly that its hard to tell if it is affected.

Goodluck!
Rich
__________________
Garrison G-20
Larrivee P-01K: Signed by Tommy E.
Simon Fay Custom
Reply With Quote
  #8  
Old 01-07-2009, 12:22 AM
birkenweg42's Avatar
birkenweg42 birkenweg42 is offline
Charter Member
 
Join Date: Apr 2004
Location: Sierra Foothills, California
Posts: 1,331
Default

Let me know if you want to go the Bridge Doctor route. I bought one two month ago but then decided I have the guitar fixed professionally. I'm glad I did. If you wnt it you can have it cheap.
__________________
Santa Cruz OM/PW, Guild F212XL and a National Resophonic Estralita Deluxe

My Youtube Channel
Reply With Quote
  #9  
Old 01-07-2009, 02:22 AM
Coffeecup Coffeecup is offline
Registered User
 
Join Date: Nov 2008
Location: Brisbane, Australia
Posts: 81
Default

When reading the title of this thread I thought it was going to solve a problem that has been troubling me for some time. Unfortunately it doesn't - it relates to guitars.
Reply With Quote
  #10  
Old 01-07-2009, 04:30 AM
dmcowles@comcas dmcowles@comcas is offline
Registered User
 
Join Date: Feb 2008
Location: Sarasota, FL, USA
Posts: 621
Send a message via Yahoo to dmcowles@comcas
Default

The first couple runs of the Carolina series guitars had some problems with tops bellying. The people at The Music Link subsequently added a lifetime warranty to that line, now reworked and expanded, and called it Recording King. If you are the original owner, there is a good chance the dealer where you bought it has some latitude to make it right. Otherwise, if you really like your Carolina, get a Bridge Doctor. They really work, and my experience with them has been that they do nothing to diminish, or otherwise modify tone. If you go that route, you'll prolly want to have a luthier or guitar tech install the BD.

Dave
__________________
I've cut this thing twice and it's still too short.
Reply With Quote
  #11  
Old 01-07-2009, 05:17 AM
Ken C Ken C is offline
Registered User
 
Join Date: Jun 2008
Location: Though a bred, born, and imprinted Texan, I live in the sw corner of Southern Mississippi.
Posts: 776
Default

Quote:
Originally Posted by BBWW View Post
Buy an original design Breedlove?

Or a bridge doctor....sorry....but they work.
I have tried the Bridge Doctor with zip success. Everyone was telling me they were a good idea and there are some guitars that come with them. Having them, or something similar, in a new guitar, I think is a good idea, but it didn't work for my application.

The consensus was that I had let the bridge "come up" too much before I installed one. This could be.

My guitar condition was that the area in front of the bridge was settling and the area behind raising. The bridge was secure to the top. (I would rather had the bridge separating from the top.)

I was told I was using it correctly.

Oh...yeah...the guitar had ladder bracing (unfortunately) and a big 17" lower bout.

Also, it was one of the bridges where the strings enter a hole in front of the bridge, exit at the back and then is pulled over the saddle. Looking at the physics of the thing, it looked like what one would do to rotate the bridge to push the front down and pull up the back.

(What are those sorts of bridges called? Other than "bad idea.")

Ken C.
__________________
E-Guitar "Ken-Trapsion"
Dean Playmate
Gibson J-45 Rosewood
Gibson J-50 Mahogany
G-40 Maccaferri arch top (2 ea.)
Kay arch top w/DeArmond floating p.u.
Harmony arch top
Silvertone flat top
Framus 12-string
Harmony tenor arch top
Gakki Yamaha FG-140
DeArmond arch top
And 14 misc.ukes.
Reply With Quote
  #12  
Old 01-07-2009, 05:26 AM
missouri.picker missouri.picker is offline
Guest
 
Join Date: Jul 2008
Posts: 2,612
Default

too much humidity.........the top is getting water logged and bulging from the excess water content. play the git if it sounds dead or deader than usual then dry it out and it will flatten back to normal. Now off course too much drying can cause it to over-flatten and buzz and possibly crack. Oh the science of relative humidity and wood.
Reply With Quote
  #13  
Old 01-07-2009, 06:41 AM
Mandarb Mandarb is offline
Registered User
 
Join Date: Aug 2008
Posts: 1,311
Default

Saw the thread title and my first thought was - eat less. As to the real question - see other responses. Good luck.
__________________
'65 Martin F65
'94 Washburn D21S
'95 Fender Am. Deluxe Strat Plus
'08 Martin HD28
Reply With Quote
  #14  
Old 09-19-2011, 03:03 PM
bosrocker51 bosrocker51 is offline
Registered User
 
Join Date: Dec 2009
Location: In a building
Posts: 9
Default bulging bridges...

I know this is an older thread, but I have to comment. A well made flat top guitar should never have the top deform, bridge tilt forward or any such thing if it is well made, properly braced and it is not abused with strings that greatly exceed it's capability to retain.

With that said, if it bulges, fixing it would not be worth it if it's a cheap guitar, IMO. If it's a fancy or valuable guitar, I'd be tempted to take it to a luthier. I have no idea what they do, but I assume it involves steaming and using long jaw wood clamps on top of shaped flats, enlarged, new bridge plate, or god knows what all to fix it...
Reply With Quote
  #15  
Old 09-19-2011, 03:37 PM
Ken C Ken C is offline
Registered User
 
Join Date: Jun 2008
Location: Though a bred, born, and imprinted Texan, I live in the sw corner of Southern Mississippi.
Posts: 776
Default

Quote:
Originally Posted by bosrocker51 View Post
I know this is an older thread, but I have to comment. A well made flat top guitar should never have the top deform,
We can stop right there. <g> This implies that if the top deforms, it was not a well-made guitar. But is it not possible to become attached to a poorly-made guitar? We become attached to poorly-made people.
At one time, ladder-braced guitars were common, and "X"-braced, which helps prevent the belly condition was not that often used...if at all. This is all an evolutionary process.

Quote:
bridge tilt forward or any such thing if it is well made, properly braced and it is not abused with strings that greatly exceed it's capability to retain.

With that said, if it bulges, fixing it would not be worth it if it's a cheap guitar, IMO. If it's a fancy or valuable guitar, I'd be tempted to take it to a luthier. I have no idea what they do, but I assume it involves steaming and using long jaw wood clamps on top of shaped flats, enlarged, new bridge plate, or god knows what all to fix it...
Some of these "poorly-made" guitars are so valuable to their owners that they pay to have the backs removed, the ladder bracing removed and "X" bracing put in. This is a LOT of work.
Why?
Couldn't they just put that money into a properly constructed guitar?
Sure!
But as much as we would like to pretend that these are but wooden boxes with wires attached, they become much more over time.
For just another guitar, I agree with you...but for an old friend, well, he deserved a little more consideration.
__________________
E-Guitar "Ken-Trapsion"
Dean Playmate
Gibson J-45 Rosewood
Gibson J-50 Mahogany
G-40 Maccaferri arch top (2 ea.)
Kay arch top w/DeArmond floating p.u.
Harmony arch top
Silvertone flat top
Framus 12-string
Harmony tenor arch top
Gakki Yamaha FG-140
DeArmond arch top
And 14 misc.ukes.
Reply With Quote
Reply

  The Acoustic Guitar Forum > General Acoustic Guitar and Amplification Discussion > General Acoustic Guitar Discussion

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Loading

All times are GMT -6. The time now is 07:48 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Copyright ©2000 - 2014, The Acoustic Guitar Forum
vB Ad Management by =RedTyger=