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Removing Bridgeplate from Vintage Martin

Posted: Fri Nov 16, 2012 3:06 pm
by Michael Stephenson
I have a 1946 Martin 000-28 that I am in the process of restoring with the help of a local luthier (new bridge, neck reset, new frets, repairing some cracks). This is a guitar that my great uncle owned and it has had the neck reset in the past as well as having the bridge sanded down to keep from having another neck reset.

When I got the guitar the bridge was off and took a lot of the wood with it - so much so that there was a hole in the guitar top. The Luthier and I removed the section of bad top and wanted to put in a slightly larger top plate to reinforce the front edge of the new piece of wood.

We noticed that the bridgeplate is tucked under the X-braces, something that I have now learned is common to older Martins. I have also learned that properly replacing these plates is not for the faint of heart.

We tried heating up the area, but were not having any luck getting the plate loose. We want to try to get it out in one piece so that we can use it as a template for the new bridgeplate. We have contemplated a few courses, such as cutting the plate along the braces and even removing the back of the guitar (which I do not really want to do) and even leaving the bridgeplate alone and adding an extension to it.

My questions: What is the best way to remove the bridgeplate on a vintage Martin? Is there an alternative way to reinforce the front edge of the new piece of soundboard without messing with the bridgeplate?

Re: Removing Bridgeplate from Vintage Martin

Posted: Fri Nov 16, 2012 3:40 pm
by Rodger Knox
There's an article on this topic in the latest issue of American Luthierie that is worth reading.

Re: Removing Bridgeplate from Vintage Martin

Posted: Fri Nov 16, 2012 3:56 pm
by John Steele
Frets.com is an excellent resource for Martin repairs.
This link from the sight:
http://www.frets.com/FretsPages/Luthier ... rplt1.html

Some of the restoration blogs could provide some help as well.
J

Re: Removing Bridgeplate from Vintage Martin

Posted: Fri Nov 16, 2012 5:00 pm
by Mark Swanson
If the top is flat and not buckled, then I'd leave it in place and just put a piece in front of it and underneath your wood patch. You'd do the least damage and alteration that way and it would be fine.

Re: Removing Bridgeplate from Vintage Martin

Posted: Mon Nov 19, 2012 3:11 am
by Michael Lewis
That is a nasty bit of missing structure in that top. I suggest you need to make a new bridge plate that is larger than the original, to spread out the load onto structurally sound top wood. This will likely change the sound a bit, though it has already been changed by the removal of top wood at the leading edge of the bridge.

I have made bridge plates by stacking .080" - .090" hard maple , .030" carbon fiber sheet, and .020" hard maple veneer,and it must lap at least 3/4" onto the solid top wood beyond the hole, and don't for get to fill the hole with spruce. I used West systems epoxy for the lamination process to build the bridge plate and used hot hide glue to attach it, gluing the maple veneer surface to the inside of the top. This leaves the thicker maple to take the brunt of the string balls. The guitars I did this repair to are still working well last time I heard. The repairs were done many years ago.

This process is a hail Mary to save the top, and is a bit more complicated than I just explained, but works well in a dire situation. Make the plate first, then fit and glue it in. Once the bridge is in place you drill the holes for the pins, you must use a block inside to back the bridge plate as the drill exits the inside surface.

Re: Removing Bridgeplate from Vintage Martin

Posted: Tue Nov 20, 2012 1:29 pm
by Michael Stephenson
Thanks for the replies. It will be a week or so before I meet with the Luthier again. In the mean time he is consulting with some of his mentors to get their take on what we should do. When we have executed a solution I will post it so that everyone knows how we chose to resolve this.