Repairing / Replacing Acoustic Guitar Bridges

Guitar Bridge (Reverse belly as seen on many Gibson guitars)

Repairing Loose Guitar Bridges A loose bridge is not an uncommon sight and can be caused by heat, insufficient glue, stress, a cracked bridge plate or gluing the bridge to a painted surface.

For an invisible repair it is essential to:

Loose bridges almost always require complete removal in order to properly repair. The only time I may opt not to remove the bridge is when only a very small amount is actually loose (like the tip of the outer wing for example) otherwise you are probably just postponing the inevitable.

The top has been cleaned of glue and the bridge is ready to reglue.

A cracked or warped bridge plate can also cause a bridge to pop loose and must be addressed before the bridge can be reglued. When the structural integrity of the top is weakened by a cracked bridge plate or loose braces the top may loose necessary stiffness and take on an excessive arch or hump behind the bridge. This "arching" of the top now places incredible pressure on the bridge and the two surfaces, no longer conforming in shape, may cause the bridge to pop loose.

Leaving an instrument in a hot car, attic or other hot environment may cause the glue to soften which can allow the bridge to shift or creep forward. Unfortunately this usually does some damage to the finish as well.

The finish in front of the bridge was damaged when
 the bridge slid forward after being left in a hot environment.
 

Replacing An Acoustic Guitar Bridge-   Bridges may require replacement for several reasons. Bridges that have come unglued and left for a long period of time can warp and twist. Cracks can develop thru the bridge pin holes or in front of the saddle and cause the bridge to split. And some may have been thinned by a well meaning repair person who was trying to lower the action without resetting the neck.
The bridge is a top brace, albeit an exterior one and should not be cracked or loose as it weakens the structural integrity of the top and can affect the tone as a result of the poor coupling. An overly thin bridge also changes the dynamics of tension/torque placed on the top and the distance of the strings from the soundboard. 

Intonation Correction Another reason we may have to replace an acoustic guitar bridge is to correct intonation problems caused by an inaccurate placement of the bridge/saddle. You can read more about this in an article detailing a Martin guitar bridge replacement to correct intonation.

View More Bridges

Factory replacement bridges- Quite frankly this is the exception rather than the rule. Basically the only time we can use a factory made bridge is on newer construction or on instruments where designs have not changed thru the years. This is normally less expensive, so when the bridge is available it is purchased thru the factory.

Bridge Conversion  (See the second picture above) Some instruments were built with bridges which incorporated adjustable saddles. These designs usually consisted of bolts, screws, nuts, washers and a large porcelain/ceramic or wood saddle. Quite frankly they often sounded bad and I've replaced quite a few. They lack good coupling and create a gap between the base of the saddle and the topt. More

I do not offer to make custom bridges for retail sale as parts (no installation). I make only that which I install.

Special Considerations

Painted Guitar Bridges - Removing certain painted guitar bridges poses another problem. Most manufactured classical guitar bridges are finished (painted) and if we must heat the bridge to remove it the finish is likely to be destroyed. This requires stripping and refinishing of the bridge after removal which make them more time consuming and costly repairs.

Plastic Inlays - Some acoustic guitar bridges have been inlayed with plastic appointments (faux pearl, ab-alony!) . These need to be removed before the bridge is heated or they are likely to go up in a cloud of smoke.

Thick Top Finishes / Poor Surface Preparation - In order to reduce prep time some manufactures of inexpensive instruments forego removing the finish beneath the bridge (others may not remove all of it). Bridges glued to finish will usually pop loose pretty quickly (these same manufacturers often add a pair of screws coverd by dot inlays as well).
When the finish is as thick has a credit card (thick polyester as seen on some imports) we must scribe around the bridge and scrape the finish away in order to glue the bridge to wood. But, the real problem I have is the end result, the cosmetic outcome. Truly thick finishes can create such a ledge between the newly scraped area and finished top that the bridge is in effect being inlayed into the finish. Yuck, it's awful and it's extremely difficult to make it look good. I personally don't touch those.

Related Articles:

Martin Bridge Replacement
Pictures of Bridge Replacements
Bridge Plate Repair/Replacement
Bridge Pin & Stringing Facts
Intonation
Saddles