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  #1  
Old 02-06-2020, 11:17 AM
hrtfxr hrtfxr is offline
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Default Bridge plate repair question

My bridge plate is badly worn. My luthier would put a thin maple cover/cap over it.
I have a long relationship with this guitar that has remarkable tone.
My questions are, will the tone be affected and is this a good way to do it? I see that there are newer techniques.
Thanks
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  #2  
Old 02-06-2020, 12:01 PM
charles Tauber charles Tauber is offline
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Stiffness is proportional to the cube of the thickness. Adding thickness will add stiffness. Will adding stiffness audibly alter the tone? You won't know for sure until after it is done.

I think there are less intrusive repair methods that can be used. One option is to use a specialized tool and insert plugs of replacement wood, leaving the bridge plate effectively unchanged, but repaired. I think that would be a better choice but would require the repair person to either invest in the tooling or make his or her own.

If you are having work done, have the bridge pin holes slotted and replace the pins with un-slotted pins. That will eliminate future wear.
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Old 02-06-2020, 02:18 PM
Howard Klepper Howard Klepper is offline
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A photo would greatly improve the quality of the advice you receive.

You can use a phone camera with a timer.
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Old 02-06-2020, 06:07 PM
mirwa mirwa is offline
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Adding another wooden plate is IMO a bad idea as mentioned above.

Thin brass plates can be installed with less concerns

The plate can be repaired by drilling and replugging each hole - best option IMO

The bridge plate can be removed and replaced - not an easy job.

Steve
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Old 02-07-2020, 10:31 AM
redir redir is offline
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Wouldn't brass be even heavier then a thin slice of wood though? I've added thin veneers before and never noticed a difference in tone. That stewmac hole plug tool bothers me a little bit because you might actually be weakening the bridge plate by drilling larger holes in it and then you are essentially driving wedges into each individual hole. I know a lot of people use it successfully though but it's just a though.

My favorite way to fix these problems I think I got from John Arnold and that is simply saw dust and glue fill and drill. But we don't know the extent of the problem, as mentioned above pics would certainly help.
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Old 02-07-2020, 06:33 PM
mirwa mirwa is offline
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Yes brass is heavier than wood gram for gram, however you can get away with a super thin piece of brass rather than a super thin piece of wood.

The bridge plate plug tool is extremely well designed and simple to use.

Steve
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Old 02-07-2020, 07:34 PM
John Arnold John Arnold is offline
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Quote:
My questions are, will the tone be affected and is this a good way to do it?
I used to do these routinely, and never noticed an adverse effect to the sound. If anything, the sound was improved, due to the more solid anchoring of the string ball.
These days, I prefer repairing the plate with CA and wood dust.
The only downside of using a hardwood 'helper strip' is when the total thickness of the bridge and the other elements is too much, and the contact point for the string ball is close to the end of the bridgepin. The small diameter there may not be sufficient, considering that the minimum size of the hole must be able to pass the string ball, which is larger than the tip of most bridgeplins. But in most cases, that is not an issue.
Bridgeplate wear is often caused by the use of slotted thermoplastic bridgepins, which distort, allowing the string ball to climb into the hole in the bridgeplate. I highly recommend slotting the bridge and using unslotted pins made of a material that is not likely to dent or distort. This can be a hard plastic (polyester or Galalith), a hard wood (ebony or similar), or bone or ivory. The unslotted type is inherently more durable.
Quote:
Yes brass is heavier than wood gram for gram, however you can get away with a super thin piece of brass rather than a super thin piece of wood.
For some inexplicable reason, PlateMates are made of brass, which is heavier than steel (never mind wood), and over three times as heavy as aluminum. IMHO, these should be made of aluminum.
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Old 02-07-2020, 08:52 PM
Otterhound Otterhound is offline
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Why not use a piece of Lexan instead of the brass Plate Mate ?
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Old 02-11-2020, 10:53 AM
John Arnold John Arnold is offline
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Lexan is certainly tough. I think Formica would also be a good choice, if going the plastic route.
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Old 02-12-2020, 06:51 AM
murrmac123 murrmac123 is offline
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Quote:
brass is heavier than wood gram for gram
Absolute classic.
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  #11  
Old 02-12-2020, 07:54 AM
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hubcapsc hubcapsc is offline
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There's a kind of very lightweight wood epoxy made by Abatron that is
strong enough to repair structural elements in buildings... once it sets it
can be worked like wood, cut, routed, drilled, etc... I wonder about
it when I read about fixing the holes in bridge plates...

https://www.abatron.com/product/woodepox/

-Mike "I can pound a 16 penny nail in a 2x4..."
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  #12  
Old 02-19-2020, 12:05 PM
pacrimcat pacrimcat is offline
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Quote:
Originally Posted by John Arnold View Post

For some inexplicable reason, PlateMates are made of brass, which is heavier than steel (never mind wood), and over three times as heavy as aluminum. IMHO, these should be made of aluminum.
From Allan, Stephen. "Which Materials Carry Sound Waves Best?" sciencing.com, https://sciencing.com/materials-carr...s-8342053.html. 18 February 2020 (who gave online permission to cite): “Sound travels at one of the fastest rates through aluminum, at 6,320 meters per second . . . the next-fastest speed for sound is 4,600 meters per second in copper.” Elsewhere I read that just being an efficient transmitter of sound doesn’t mean that the frequencies you value most are what is going to get heard, i.e., there were a handful of companies in the late 1800’s that made aluminum guitars, banjos, mandolins and violins that were just “okay” instruments, and one author described the aluminum "sound" as solid and chunky.

Copper is the next best element and adding tin makes bronze, which is harder/stronger and more brittle than brass. Bronze is used in bells and cymbals and noted for being very efficient, durable, with a lot of sustain and pleasant to the ear. So, I am thinking of using bronze and hoping that the string manufacturer’s use of bronze is a positive sign that bronze is the way to go.

Aluminum weighs about a third of what brass and bronze weigh but isn't as strong, so maybe I can use just a very small 3” x ¼” x 1/32” strip of bronze to abut my non-slotted bone pins. My 1954 Martin 00-17 already had the bridgeplate replaced prior to my buying it in 1978. A luthier is doing the Bridgesaver repair next week and I am then going to consider trying the bronze strip as “preventive maintenance” for my newly repaired bridge plate and hoping that it doesn’t change the tone. I am a “tractor guy”, not experienced in any of this, just did a little reading on the internet to post this and solicit opinions as to whether I am on the right track or on the wrong track, as I want to pass this guitar on to my kids/grandkids.
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  #13  
Old 02-19-2020, 01:52 PM
John Arnold John Arnold is offline
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It's not about strength or sound transmission, it is about protecting the bridgeplate from wear without adding unnecessary weight. Adding weight will reduce volume. Aluminum is plenty hard enough for this application. So is Formica.
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  #14  
Old 02-19-2020, 03:07 PM
pacrimcat pacrimcat is offline
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Okay, thanks. For my application with slotted bridge and unslotted pins, the 3" adequately covers the length and I copied PlateMate's 1/32" thickness for a proposed 3” x ¼” x 1/32” bronze plate (weighing 2.7 grams)

As a starting point for aluminum, with a 3" plate length, what dimensions would you suggest for depth and thickness?

Help me with the starting dimensions and I will complete the test in April (2020!)
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  #15  
Old 02-20-2020, 03:32 AM
Hamptonguitar Hamptonguitar is offline
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Quote:
Originally Posted by charles Tauber View Post
Stiffness is proportional to the cube of the thickness. Adding thickness will add stiffness. Will adding stiffness audibly alter the tone? You won't know for sure until after it is done.

I think there are less intrusive repair methods that can be used. One option is to use a specialized tool and insert plugs of replacement wood, leaving the bridge plate effectively unchanged, but repaired. I think that would be a better choice but would require the repair person to either invest in the tooling or make his or her own.

If you are having work done, have the bridge pin holes slotted and replace the pins with un-slotted pins. That will eliminate future wear.
I’m currently having a 1980 Martin repaired using exactly this method.
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