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PostPosted: Mon Sep 12, 2022 3:20 pm 
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Joined: Wed Oct 08, 2008 11:36 am
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Location: Southeast US
City: Lenoir City
State: TN
Zip/Postal Code: 37772
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Focus: Repair
Another one here. I tape off the bridge and fretboard areas with Frisket before finish. Frisket is thinner than masking tape so it doesn't get in my way. After I take it off I scrape with a razor blade before gluing on the bridge and fretboard.

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PostPosted: Tue Sep 13, 2022 2:28 am 
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Old Growth Brazilian Rosewood
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Joined: Fri Nov 02, 2007 9:49 am
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Location: Ann Arbor, Michigan
First name: Hesh
Last Name: Breakstone
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Juergen wrote:
Hi Clay,
that`s the real truth, that we as amateurs can make a lot of mistakes without having nothing to eat next week :)
But as Hesh describes it is commen in the classical world to finish after glueing everything in place. On the other hand lifted or pulled off bridges are his daily repair work, and I have tried to find a possible answer in the way finishing is done beyond all other possibilities like bad glueing, not well done glueing surfaces etc.


Juergen build what you want how you want to build it and here is wishing you the best of luck with what you do.

It's my belief and experience and I am not alone either that all glue joints may fail in time and space or given the right circumstances. With guitars it's a question of when for a bridge to lift not if and as such makers should do what it takes so the instrument is serviceable in time and can live to play again after the bridge is reglued. I feel the same way about neck resets and Martin guitar just changed their view too to now expect that neck resets will be needed making them more normal wear and tear than a defect eligible for warranty service.

When you glue a bridge and clear finish to the perimeter and it's a steel string with a lot of tension we often see bridges plowing the finish on the leading edge before they lift on the back edge. Once this happens the top finish is visually compromised and the bridge footprint on the guitar top is larger than the bridge. This then requires finish touch-up and doubles the effort and price of the repair not to mention the time to complete. And it's not necessary.

Now your math on losing 10% of the gluing surface for rabbiting a bridge is flawed and incorrect. We estimate maybe 1.5 - 3% on a Martin style bridge with a rabbit .010" in from the perimeter. We did the math yesterday and that's what we arrived at.

There is also the issue of a non rabbited bridge spanning the finish ledge where the drop off where the finish ends prevents wood to wood connection for some distance inward. A rabbit eliminates this and where it's intended to have full wood-to-wood contact that's indeed what it has.

Others who rabbit bridges include some of the best makers in the world such as Collings Guitars.

Regarding your dismissal of using film when Professional Finishers and amateurs alike use it with no issues is also incorrect with your statement about residual adhesive. We remove that and in fact no bridge or bridge patch in our shop ever gets HHG applied until it has been freshly scraped with a very sharp scraper removing contamination and then debris is vacuumed off and then we glue.

And your statement about the top being weakened by finish clean-up or removal is not accurate either. As Eric Reid posted we do the same, very sharp chisel and some skill... and no wood or very little is removed just finish. We use very sharp chisels to expand the gluing area on lifted bridge to near the perimeter and then we rabbit. The bridge is also a brace and one of the most important braces on a guitar. If you were correct and you are not that cleaning the bridge patch weakens that's more than countered with a bridge slapped on top....

But again do whatever you want and I hope it works out for you.

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PostPosted: Tue Sep 13, 2022 4:11 am 
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Brazilian Rosewood
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No rabbets were harmed in the making of this thread.



These users thanked the author meddlingfool for the post: Hesh (Tue Sep 13, 2022 8:15 am)
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PostPosted: Tue Sep 13, 2022 6:20 am 
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Brazilian Rosewood
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meddlingfool wrote:
No rabbets were harmed in the making of this thread.


Rabbity, rabbety, rebates -buy a bunny, get a rebate on rabbits! bliss

Hesh wrote:
"When you glue a bridge and clear finish to the perimeter and it's a steel string with a lot of tension we often see bridges plowing the finish on the leading edge before they lift on the back edge. Once this happens the top finish is visually compromised and the bridge footprint on the guitar top is larger than the bridge. This then requires finish touch-up and doubles the effort and price of the repair not to mention the time to complete. And it's not necessary."

This is one of the things I referred to when I mentioned the "next guys" problem. For Classical guitars with well fitted bridges and French polished finishes it is less of a problem than for steel string guitars with greater string tension and often tougher but more difficult to repair finishes.
Some repair people add a big honking bridge to save the finish repair work. [uncle]



These users thanked the author Clay S. for the post: Hesh (Tue Sep 13, 2022 8:19 am)
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PostPosted: Tue Sep 13, 2022 8:27 am 
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Old Growth Brazilian Rosewood
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Joined: Fri Nov 02, 2007 9:49 am
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Location: Ann Arbor, Michigan
First name: Hesh
Last Name: Breakstone
City: Ann Arbor
State: Michigan
Country: United States
Status: Professional
Clay S. wrote:
meddlingfool wrote:
No rabbets were harmed in the making of this thread.


Rabbity, rabbety, rebates -buy a bunny, get a rebate on rabbits! bliss

Hesh wrote:
"When you glue a bridge and clear finish to the perimeter and it's a steel string with a lot of tension we often see bridges plowing the finish on the leading edge before they lift on the back edge. Once this happens the top finish is visually compromised and the bridge footprint on the guitar top is larger than the bridge. This then requires finish touch-up and doubles the effort and price of the repair not to mention the time to complete. And it's not necessary."

This is one of the things I referred to when I mentioned the "next guys" problem. For Classical guitars with well fitted bridges and French polished finishes it is less of a problem than for steel string guitars with greater string tension and often tougher but more difficult to repair finishes.
Some repair people add a big honking bridge to save the finish repair work. [uncle]


Good point Clay and it's VERY important to us to not create a "next guy's problem" for anyone from anything we do. Serviceability is our North Star in our shop and it became my North Star for building after I began to learn the repair side of the business.

I wish that I could draw because the finish ledge issue I mentioned above has a rather dramatic point to make. Say you have .005" thick finish under the bridge. If the bridge sits on the finish and is not rabbited there will be no wood-to-wood contact for a goodly amount of space inward from the bridge premier. If the bridge was flexible like putty this would not be the case. So I'm guessing that if a bridge has to be in contact with the finish at all this can be an issue.

Our rabbits are sized so that the bridge may be a very slight distance above the finish on the underside of the cut-out. Every guitar is different so our bridge fitting is always an individual thing. Maybe a thou or two. It's really quite eloquent and we have never had a rabbited, HHG bridge from us lift. I'm sure it will happen since we can't control what people do with guitars and when it does we can glue it back down and no finish touch-up will be necessary and the repair will be completely invisible. That's what serviceability means. :)

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