How do I remove "layers" of PVA glue from bridge area on 1980 Martin D-35

[Jim Glenn]

I'm new here and hope that I'm not asking a question that has been covered many times before.

I purchased a 1980 D-35 recently that has had a history of the bridge coming off.  The bridge was glued down on it when I got it, but popped off after about 6 months. I can see that there have been a number of different attempts to re-glue the bridge during it's life. I purchased a bottle of De Glue Goo and tried using it to soften and lift the PVA glue, but apparently did not get as much off as I thought I had. I tried re-gluing it last week and after letting it set for 48 hours, the bridge came up as I was bringing the strings up to pitch. It seems as though the pores of the wood are sealed by previous glue attempts. I'm hoping that there is a better product or procedure available that I'm not aware of. This guitar has amazing sound when it is playable, so I want to do everything possible to rescue it.

[Mark Pollock]

Pictures are a big help. Beyond that, careful scraping is needed, and you also want to make sure that the bridge is truly making 100% contact with the top. Any gaps will completely sabotage your glue up.

How are you clamping this?

[Jim Glenn]

Seems as though there are several things going on here that are working against a successful glue job. After examining the guitar top  where the bridge attaches, I can see that I did not have it flattened out sufficiently for the bridge to make full contact. I'm going to start over with the De Glue Goo and try again to totally remove 100% of the old glue, then get shoot for 100% contact. Thanks for your response.

[Jeff Highland]

I have not use deglue goo as it is not available here.

Once you have started to use it, if you have not removed all the old glue completely it would be a weak layer. You absolutely need to get back to fresh scraped wood. You should also go for wood contact over the full bridge footprint not the 1/8" inside that Martin typically used till recently

Does anyone neutralize the wood after using this product? Remnants of acetic acid can not be good.

Also worth checking the condition of bridge plate and braces in case there was a structural reason for the multiple bridge failures.

[Paul Verticchio]

Hi Jim.

To get you the best & most relevant answers, could you give us a little background on your experience with guitar repair and skill level.

Your continued reference to DeGlueGoo leads me to believe you have minimal experience. Scraping is the preferred and industry standard method. Also, answering Mark's question about your clamping methods will be of significant benefit.

Thanks and best of luck :)

[Jim Glenn]

My experience with guitar repair has a gaping hole in it. During the '70's I did quite a lot of repair work on guitars and mandolins, primarily on bluegrass instruments that I purchased and resold. Hide glue was the only thing that I worked with and was very comfortable with its' properties. I gradually got away from any repairs until just recently. PVA glues and their properties are a mystery to me. I realize that my thinking is pretty outdated, but certainly prefer working with hide. I put off reattaching this bridge for a couple of months hoping that I would find something that would loosen the PVA so that I could get back down to bare wood. Stew Mac sent out an email a few weeks back extolling the virtues of De Glue Goo and it sounded like what I needed.

I use a homemade bridge clamping caul that is fairly similar in design to the one that is sold be Stew Mac

[Mark Pollock]

There are a LOT of folks here who would say that hide glue is still the best stuff, although your joint might be contaminated enough that it should be avoided. Now I'm curious to hear folks thoughts on what glue to use in this situation. 

[Jim Glenn]

I would also be be interested in what the forum member recommend. I've been in a quandary as to what type of glue would best fit in these circumstances.

[Jeff Highland]

I doubt you will find anyone here discouraging you from using HOT hide glue

It's all I use for bridges.

[Jeff Highland]

There are a few things  which contribute to bridges coming off

-margin of finish around the edge reducing gluing area and giving a thicker glue line

-Hot car

-broken bridgeplate or braces

I'd be putting the bridge in place, tracing around it and then scraping down the  whole area to  fresh wood even if you lose a few thousandths of an inch, then glue with HHG

[Jim Glenn]

This Martin has been refinished at some point in it's life. Because of how it was done, the finish line butts up the bridge, but does not extend under it.

I've been all over the inside of the guitar with a mirror and inspection light and haven't found anything in the way of cracked or broken braces, bridgeplate, etc. As for the hot car, I can't say what has happened before I got it,but I'm a real fanatic about never putting a guitars into hot cars. I have several vintage Martins and I'm very careful about temperature changes or extremes.

Does PVA glue penetrate into the wood and seal it, or once I remove it from the surface will it be open to accepting hide glue?

BTW- does anyone else out there use a baby bottle warmer to keep hide glue at the proper temp?

[Jeff Highland]

I use a baby bottle warmer

Spruce is relatively non porous but you will have to take the top off the surface

[Robbie Collins]

Make sure you scrape and level the bottom of the bridge. Also, don't assume the bridge was located correctly to begin with.