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PostPosted: Mon May 17, 2021 11:52 am 
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Koa
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Any creative solutions for re-gluing the bridge on this tiny guitar with very unconventional bracing and very small offset soundhole?


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PostPosted: Mon May 17, 2021 2:51 pm 
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A stack of books? Not kidding - did it that way once or twice when nothing else would work.

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These users thanked the author Chris Pile for the post: Conor_Searl (Mon May 17, 2021 3:36 pm)
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PostPosted: Mon May 17, 2021 3:51 pm 
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Brazilian Rosewood
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Re-top it?

:D

If you have a tremendous amount of patience and some special curved and long forceps you might be able to wedge some 'go bars' under the bridge patch and clamp it from the outside. Perhaps using magnets to align them.



These users thanked the author jfmckenna for the post: Conor_Searl (Wed May 19, 2021 3:21 pm)
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PostPosted: Mon May 17, 2021 4:20 pm 
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Koa
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Make sure the fit is perfect (as always) and use HHG. Hi clamping pressure not necessary. At least it has bridge pins to help keep it aligned.


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These users thanked the author Tim Mullin for the post: Conor_Searl (Wed May 19, 2021 3:21 pm)
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PostPosted: Mon May 17, 2021 10:21 pm 
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Like Tim says, perfect fit and HHG. Then a vacuum clamp.

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These users thanked the author Pat Foster for the post: Conor_Searl (Wed May 19, 2021 3:21 pm)
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PostPosted: Tue May 18, 2021 3:38 am 
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Rare earth magnets are really handy for something like this.

I'd use HHG and hold the bridge in place with hand pressure until the glue grips it.

Then apply the rare earth magnets outside, taped to some card taped to the bridge, then magnets inside applied on the end of a bent stick.

Finally heat the bridge to reactivate the glue, then leave overnight before removing the magnets.



These users thanked the author profchris for the post: Conor_Searl (Wed May 19, 2021 3:21 pm)
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PostPosted: Tue May 18, 2021 11:31 am 
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Koa
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Tim Mullin wrote:
Make sure the fit is perfect (as always) and use HHG. Hi clamping pressure not necessary. At least it has bridge pins to help keep it aligned.


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Is hi clamping pressure unnecessary because of the use of HHG, or simply not necessary for regluing a bridge?


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PostPosted: Tue May 18, 2021 11:32 am 
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Koa
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profchris wrote:
Rare earth magnets are really handy for something like this.

I'd use HHG and hold the bridge in place with hand pressure until the glue grips it.

Then apply the rare earth magnets outside, taped to some card taped to the bridge, then magnets inside applied on the end of a bent stick.

Finally heat the bridge to reactivate the glue, then leave overnight before removing the magnets.


Do you think this method could work using original tite-bond? I've never used HHG. The extra open time of tite-bond could mean not having to re-heat the bridge once magnets are in place.


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PostPosted: Tue May 18, 2021 11:43 am 
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Pat Foster wrote:
Like Tim says, perfect fit and HHG. Then a vacuum clamp.


Vacuum clamps are slick! I'd never looked at them too closely. That might be the perfect trick.


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PostPosted: Wed May 19, 2021 1:50 pm 
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Koa
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You have some good advice here. I've done these before, they're interesting.

Make sure the fit is perfect (100% perfect no exceptions) and use HHG or Old Brown Glue. I made a little micro go bar deck that only reached over the bridge area (like a 1x3) and would screw to the bench. That way it was super easy to get equal pressure on all parts of the bridge and to get it aligned correctly. If you want I can draw it out for you but you're pretty smart and could probably figure it out.



These users thanked the author DanKirkland for the post: Conor_Searl (Wed May 19, 2021 3:21 pm)
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PostPosted: Wed May 19, 2021 3:22 pm 
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Koa
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DanKirkland wrote:
You have some good advice here. I've done these before, they're interesting.

Make sure the fit is perfect (100% perfect no exceptions) and use HHG or Old Brown Glue. I made a little micro go bar deck that only reached over the bridge area (like a 1x3) and would screw to the bench. That way it was super easy to get equal pressure on all parts of the bridge and to get it aligned correctly. If you want I can draw it out for you but you're pretty smart and could probably figure it out.


So the go bars are exerting pressure from the outside, but there's nothing inside?


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PostPosted: Wed May 19, 2021 3:33 pm 
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Conor_Searl wrote:
DanKirkland wrote:
You have some good advice here. I've done these before, they're interesting.

Make sure the fit is perfect (100% perfect no exceptions) and use HHG or Old Brown Glue. I made a little micro go bar deck that only reached over the bridge area (like a 1x3) and would screw to the bench. That way it was super easy to get equal pressure on all parts of the bridge and to get it aligned correctly. If you want I can draw it out for you but you're pretty smart and could probably figure it out.


So the go bars are exerting pressure from the outside, but there's nothing inside?


Not quite. You want maybe 14-16" of space between the beam and the bridge. I used small cutoffs from tops as the pressure bars. You can drill little spots into the bar to give them something to hold onto while you place them. This way you have access to the bridge during the glue up. Sorry I wasn't more clear previously.


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PostPosted: Wed May 19, 2021 3:38 pm 
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Brazilian Rosewood
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I think what conor is saying is that with that gobar set up there is no opposing force from the inside. That's why I was suggesting putting gobars on the inside so that when you clamp you have something to take the pressure. I'm sure it would work though. You just have to be careful applying pressure to the bridge that is not supported on the inside. I have done this before and it works. You don't get ideal clamping pressure but as mentioned a good fit with HHG is probably good enough, that with a bit of pressure even better.

It would be a PIA to get gobars inside that thing but violin makers do something similar with the sound post.



These users thanked the author jfmckenna for the post: Conor_Searl (Wed May 19, 2021 4:30 pm)
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PostPosted: Wed May 19, 2021 4:21 pm 
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How about inflating a balloon inside to provide the opposing pressure to the gobars or to the Pile of books?



These users thanked the author CarlD for the post: Conor_Searl (Wed May 19, 2021 4:31 pm)
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PostPosted: Wed May 19, 2021 4:31 pm 
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Koa
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jfmckenna wrote:
It would be a PIA to get gobars inside that thing but violin makers do something similar with the sound post.


This is why violin makers are the real luthiers right? beehive



These users thanked the author Conor_Searl for the post: jfmckenna (Thu May 20, 2021 9:49 am)
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PostPosted: Wed May 19, 2021 7:24 pm 
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Koa
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Nobody HAS to do any job. If OP is not experienced in this job on this sort of guitar, I think he can encourage the owner to look elsewhere without feeling bad about it. This repair is sounding like a time-and-materials job and the owner's gonna faint when he sees the bill. Or OP will have given his time away on an unprofitable job.

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PostPosted: Thu May 20, 2021 11:35 am 
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No need to complicate this. As stated by experienced repair folks here, HHG is recommended because (1) it’s by far the easiest glue to clean up and (2) it will literally pull a well-fitted joint together. Some classical builders would argue “no clamping required”, i.e., a “rub joint”. Some VERY LIGHT pressure can be organized in a go bar deck, without any distortion of top or bridge. No interior bars, magnets, or cauls. And once you use HHG for a bridge, you’ll never go back.


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These users thanked the author Tim Mullin for the post: Conor_Searl (Thu May 20, 2021 12:17 pm)
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