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I'm a newb to the world of lutherie , but looking to make this my retirement hobby. A long time player and tinkerer on my own stuff I realized I enjoyed doing this and thought I'd work start slow and work up to building things.  I started with my own collection (dozen basses, guitars, etc) and some yard sale rejects.  However, this big opportunity fell into my lap when I was back home for a visit this summer. 

My brothers prized '73 Guild F112 had the bridge pulled up on the bass side and the top has a slight belly bulge.  Apparently, it had been that way for many years.  I offered to take a crack at it (free of course) which my brother agreed to, so I brought it home to California (I live not far from Franks shop, Gryphon Instruments.) When I removed the bridge the top underneath the loose side had fine wood 'hairs' - not typical tear-out from what I can tell <see photo>.  As I said, I'm new to this, so maybe you've all seen this type of damage.

My first question to everyone is, do I try to glue that stuff back down first, or just clean it up and start fresh, hoping there's enough top left for support?  Or do I have to patch in some new wood?

I also found a loose brace which may be the root cause of the bridge problem.  Its the one behind and right up against the bridge plate and really hard to get to, so I reasoned it might be easier to remove it altogether and clean then reglue rather than try to work it in place.  I was able to use a hot palette knife to loosen it. However, working blind I also poked the knife right through and split it. Real rooky move, but then I'm a real rooky. The other end also split a little. 

So can I get away with gluing that back together, or is it new brace time?  I'm assuming I'll have to solve the brace problem first before regluing the bridge.

I also intend to put a Bridge Doctor in.

Thanks in advance.

Bruce

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Yup -

No problem to flatten if it doesn't make the bridge too thin or ugly (uneven thickness at the ends - that sort of thing.   If it is just a bit twisted, cupped or otherwise uneven, it can still be successfully glued to the top, which will bend a bit under clamping pressure to conform.  Either way, the gluing surface, glue, and clamping pressure will be the determining factors.

About the brace that split when I was removing it - the split is only about an inch and a half. Is gluing it OK, or do I need to replace it?

Thanks Frank

Heating and clamping flat will also fix a twist.

I use 3/4" thick Aluminum scrap I got from a local machine shop to cut up for various size heating cauls. A piece large enough to accommodate a bridge is my heater. The bridge is whetted by wrapping it with wet paper towels. Whetting generates steam and helps coax the bridge flat. The glue residue on the bridge has been lightly scraped off before whetting. The Aluminum bar is heated up on a hot plate to no more than 350 degrees, any more than that will start to burn the wood. I monitor the temperature with a bi-metallic thermometer I bought from Stew Mac. Once the Aluminum is up to temperature, clamp the whetted bridge to it and leave it until cool. Leather gloves recommended to quickly handle the hot Aluminum bar and get the bridge clamped on! Use clamping cauls or you may leave dents in the top of the bridge.

What happened to the attach image button? All I get is a simple field for copy only when I click reply.

Excellent advice Paul.  I had started thinking along these same lines, but your response gets me to the goal. Luckily I work at a place that has a comprehensive shop that should have some suitable scrap.

Yes, I'd love to see those pictures.

Hmm, edit option not working either. Just tried that to see if I could add images there.

Looks like the editing fields are working today....

Just to be clear, the wet paper towels are just a convenient way to introduce some moisture into the bottom side of the bridge to generate a bit of steam. They are not left on the bridge when it is clamped to the hot Aluminum.

Not too much more info looking at the pictures Bruce but here you go.

I reread your initial questions, did you break one of the X braces?

Thanks for the pix Paul. Good stuff.  I was able to pick up a couple aluminum pieces at work. They're only 3/8" but should do the job.  Not sure if bolting them together buys me more joojoo.

And yes, I broke the brace.  I just skewered it with my palette knife which caused a split down to the bottom about 2 in total.  The brace came off fairly easily at that point.  Also one end split, but came off clean. I glued everything back with Titebond.  Here it is before gluing. After gluing it seems structurally pretty sound.

Bruce, the 3/4" thick Aluminum will hold the heat longer. I think the 3/8" would be OK if you just stack and heat two loose pieces the same size, then clamp it all up together.

Your image does not look like an X brace, fortunately, that would have required removing the back of the guitar.

Good luck...

Correct, its a secondary brace directly behind the bridge plate.  There is one more behind that, I guess because its a 12 string.

So, in your opinion would the original glued up brace work, or do I need to build a new one?

The split is not so bad and could be glued. Some of the bottom surface looks chewed up but it would not affect the brace enough to worry about if you sanded some off of the bottom to clean it up. The other side of the coin is that you now have a template for a new brace. I personally think you could go with either option.

Here is another image for you, an easy way to sand the underside of the top where the replaced brace will go. I use magnets for this, the inside magnet has sticky back sand paper on it, works very well.

Clever.  I'll try that.  I think what you are seeing on the bottom of the brace is glue, not rough wood.  I've already sanded that on my Perma-Grit sanding block (marvelous device)

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