I recently bought a 1969 Gibson B25 12-string needing repair. It has the adjustable bridge and trapeze tailpiece. A well-meaning but clueless person glued an almost 1/4 inch thick piece of rosewood filling almost all the area from behind the bridge plate to the lower face brace. I've probed to check the strength of the glue joint, and it's very well attached. I'm concerned that using my bridge plate iron in an effort to soften the glue line on such a thick piece of wood might damage the top. Other than softening the glue line with heat, the only other way I can think of is to mechanically remove the patch in pieces with chisels and sandpaper, which may wreck my forearm. I would really appreciate any advice or ideas. Thanks!
Hi Harry, my first thought was why was that oversized plate put there? The fact that there is also a tailpiece and adjustable bridge leads me to think that the top, in its original condition, was in a really bad way. So, I'm thinking that removing that heavy timber reinforcement is still going to leave you with a top to fix, or a neck to reset.
You may want to investigate if a new top might be the better option.
Thanks very much for your reply! The main issue with the B25 is cracks on each side of the fingerboard extension with the neck block and attached top collapsing into the soundhole. I've had good luck using a jig to clamp the neck, block, and top back into the correct position and reglueing and reinforcing it while clamped. Anyway, the bracing looks very clean and well attached, and there is no visible warping of the top or braces. In any case, I really want to get that huge piece of rosewood off the top. If there is any give under string tension, I can go with much lighter spruce reinforcement later. Thanks again!
Hi again, I hear you with the neck issue, I've had a few of those very same neck block area repairs recently. The last one was a real challenge.
Good luck, oh, and I have had the forearm problem too, I had a row of bruises on my arm for the rest of the week after the job was done. Hahaha.
When I remove bridge plates, I first soak them with a damp to not quite fully wet sponge overnight. You need to use cellulose sponge. Other types of sponge allow the water to drain out, you don't want that. Cut the sponge the shape of the piece to remove, it cuts easily when it's dry. You can cut the thickness too. Place it on the piece to remove with the guitar on it's face. When you hit it with a hot bit of metal you want it to generate a bit of steam, so get the iron good and hot. I use thick aluminum, which is easier to cut into specific shapes. Put a threaded hole in it and make a handle out of threaded rod. I've pulled large Rosewood bridge plates out of Martins fairly easily doing this. The thicker Rosewood you describe might need to soak more than over night. Sounds like a real P.I.T.A.! Can you even get to an edge that you can hook the bridge plate to pull it?
Option B is to remove the back.
Thanks very much for the advice, Paul. I can get to the back edge with a hook. Luckily, I have skinny arms! I do have the Stewmac bridge plate iron. I will remove the back if necessary, but the back and sides are so clean that I'd really like to avoid that if possible.