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  #16  
Old 07-12-2013, 10:03 AM
Tom West Tom West is offline
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Heat lamp is my tool for this job.
Tom
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  #17  
Old 07-12-2013, 10:06 AM
YamaYairi YamaYairi is offline
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Quote:
Originally Posted by charles Tauber View Post
You don't need any clamps. I encourage you to think creatively.

I use two 3/16" diameter machine screws with 4 washers and 4 matching wing nuts. I use two gluing cauls. The first goes on the inside of the guitar and matches the size and shape of the bridge plate. The second goes on top of the bridge and is the shape of the bridge to be glued. Through the two cauls, I drill two 3/16" holes that match the two outside strings (high and low E).

Clamping is accomplished by inserting the two screws through the "sandwich" of, from inside out, the bridge plate caul, the bridge plate, the top, the bridge and the bridge caul. The screws go through the outside two holes of the bridge and sandwich. On the inside is one washer and one wing nut per screw. On the outside is one washer and wing nut per screw. If needed, I use pliers on the outside wing nuts to tighten it down. (I don't use the head on the screws for two reasons: 1) I can get more torque with pliers than a screw driver and 2) if the screw driver slips, as they often due, even with Robertson head screws, damage to the guitar will almost certainly be the result.)

Once the "sandwich" is tightened down, I use a pair of small wooden wedges at each end of the bridge, wedged between the bottom of the bridge caul and the top of the bridge. In each pair, the wedges are inserted opposite to one another and squeezed inwards, creating downward pressure on the "wings" of the bridge.

The two cauls can be made of plywood or solid wood.

No clamps required. Easy to clean up the glue, if the bridge caul is shaped to match the bridge. I've used this method for 30 years. It works very well, at least for me.

EDIT: don't forget to wax the bridge plate caul's mating surface. Guitars don't sound very good with the addition of a permanently attached 3/4" thick plywood bridge plate. (Alternatively, you could use a piece of wax paper instead of wax.)
Brilliant!
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  #18  
Old 07-12-2013, 04:45 PM
kennyk kennyk is offline
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Quote:
Originally Posted by arie View Post
just don't hit the "steam" button. in fact, drain the water out of the iron completely.
I think a bit of steam might help melt the glue.
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  #19  
Old 07-12-2013, 06:31 PM
Ned Milburn Ned Milburn is offline
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Quote:
Originally Posted by charles Tauber View Post
You don't need any clamps. I encourage you to think creatively.

I use two 3/16" diameter machine screws with 4 washers and 4 matching wing nuts. I use two gluing cauls. The first goes on the inside of the guitar and matches the size and shape of the bridge plate. The second goes on top of the bridge and is the shape of the bridge to be glued. Through the two cauls, I drill two 3/16" holes that match the two outside strings (high and low E).

Clamping is accomplished by inserting the two screws through the "sandwich" of, from inside out, the bridge plate caul, the bridge plate, the top, the bridge and the bridge caul. The screws go through the outside two holes of the bridge and sandwich. On the inside is one washer and one wing nut per screw. On the outside is one washer and wing nut per screw. If needed, I use pliers on the outside wing nuts to tighten it down. (I don't use the head on the screws for two reasons: 1) I can get more torque with pliers than a screw driver and 2) if the screw driver slips, as they often do, even with Robertson head screws, damage to the guitar will almost certainly be the result.)

Once the "sandwich" is tightened down, I use a pair of small wooden wedges at each end of the bridge, wedged between the bottom of the bridge caul and the top of the bridge. In each pair, the wedges are inserted opposite to one another and squeezed inwards, creating downward pressure on the "wings" of the bridge.

The two cauls can be made of plywood or solid wood.

No clamps required. Easy to clean up the glue, if the bridge caul is shaped to match the bridge. I've used this method for 30 years. It works very well, at least for me.

EDIT: don't forget to wax the bridge plate caul's mating surface. Guitars don't sound very good with the addition of a permanently attached 3/4" thick plywood bridge plate. (Alternatively, you could use a piece of wax paper instead of wax.)
Nice method!!

I had some bamboo flooring left over from my dining room, and I find it works great for cauls, since titebond won't stick to the finish. I don't need to wax, nor do I need wax paper, when using this wood as cauls. (Although I always have wax paper handy for other gluing operations.)
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  #20  
Old 07-13-2013, 01:33 AM
arie arie is offline
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Quote:
Originally Posted by kennyk View Post
I think a bit of steam might help melt the glue.
I don't. It's not a neck joint so steam won't help. The finish surrounding the bridge will take on a new form of life after the steam has had it's way with it unless you have protected the area really, really, well.
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  #21  
Old 07-13-2013, 10:28 PM
nate clark nate clark is offline
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Quote:
Originally Posted by reality View Post
@nate

I will most probably have to do it myself.. Could u tell me more about removing the bridge cause i really dont know much about the heat blanket stuff..isnt there another way to soften the glue??
You can use a heat lamp to warm up the bridge/soften the glue, just be sure to mask the top with aluminum foil wrapped around a piece of cardboard wih the shape of the bridge cut out from the center.
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  #22  
Old 09-06-2014, 12:58 PM
krm27 krm27 is offline
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Sorry to bump an old thread, but the discussion of using cauls to clamp bridge has me totally confused... I'm looking at an old, inexpensive classical guitar with the bridge off of it...there are no holes in the top under the bridge. The caul system seems to involve having screws going through the top of the guitar and through the bridge itself, but I have no holes there. In fact, I never heard of acoustic guitars having holes going from above the bridge and through the top of the body. So I'm wondering if I'm just misunderstanding the explanation. Can anyone clear this up? If I can avoid buying new clamps to fix my bridge, I'm all for it.

Ken
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  #23  
Old 09-06-2014, 01:15 PM
charles Tauber charles Tauber is offline
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Quote:
Originally Posted by krm27 View Post
Sorry to bump an old thread, but the discussion of using cauls to clamp bridge has me totally confused... I'm looking at an old, inexpensive classical guitar with the bridge off of it...there are no holes in the top under the bridge. The caul system seems to involve having screws going through the top of the guitar and through the bridge itself, but I have no holes there. In fact, I never heard of acoustic guitars having holes going from above the bridge and through the top of the body. So I'm wondering if I'm just misunderstanding the explanation. Can anyone clear this up? If I can avoid buying new clamps to fix my bridge, I'm all for it.

Ken
It isn't the use of cauls that has you confused, but rather the use of screws (bolts) through a bridge with pin holes.

Obviously, one cannot put screws through the holes in a bridge that does not have bridge pin holes, such as a classical guitar bridge or some pinless steel string guitar designs. However, when using traditional clamping methods, regardless of a pin bridge or painless bridge, one should use clamping cauls, typically one on the inside and one on the outside of the guitar.

The interior clamping caul should fit either over or around the bracing on the interior of the guitar. The exterior caul can be stepped and shaped to conform to the contour of the bridge, or not. Used together, the cauls distribute the clamping forces and prevent the clamps from damaging guitar services.

Generally, the cauls are used in conjunction with clamps that fit through the sound hole and squeeze the assembly of the cauls, bridge, and top.

If one attempts to clamp a pinless bridge to the top using clamps that span the outer surfaces of the top and back one runs the risk of crushing the top or back and splitting them.
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  #24  
Old 09-06-2014, 11:57 PM
Ned Milburn Ned Milburn is offline
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Quote:
Originally Posted by krm27 View Post
Sorry to bump an old thread, but the discussion of using cauls to clamp bridge has me totally confused... I'm looking at an old, inexpensive classical guitar with the bridge off of it...there are no holes in the top under the bridge. The caul system seems to involve having screws going through the top of the guitar and through the bridge itself, but I have no holes there. In fact, I never heard of acoustic guitars having holes going from above the bridge and through the top of the body. So I'm wondering if I'm just misunderstanding the explanation. Can anyone clear this up? If I can avoid buying new clamps to fix my bridge, I'm all for it.

Ken
You can still use Charles' method on a classical, but it means drilling holes in either the saddle slot (if wide enough) or better still, the tie block. The tie block would then need to be re-capped with a veneer or mosaic (available at Luthiers mercantile), or the drill holes filled with an inlay dot.

You will need to build a caul for the inside of the guitar that matches the camber or flatness of the original build of the guitar. If you aren't sure, a slight camber should be fine. (About half to three quarters of a mm center deviance along the length of the bridge.)

If you use C-clamps, you can use a system of above-bridge cauls where only 2 clamps are required, but it is easiest in the beginning to try a 3 clamping system - a clamp for the tie-block/saddle holder, then one each for the wings.
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