Re-topping

Even if it ain't broke you can still fix it.
Ben-Had
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Joined: Fri Sep 03, 2010 2:14 pm
Location: Creedmoor, NC

Re: Re-topping

Post by Ben-Had »

Thanks. While I'm waiting for the top to cure and for final finishing I thought you might be interested in what caused this top to need replacing. Here is my diagnosis, let me know what you think and If you have any theories of your own based on the pic provided.

It seems there may have been a perfect storm of issues here are the measurements: top thickness .092, bridge plate thickness .098. Also, notice the bridge plate placement, the back side of the bridge is extending past the bridge plate. You can see (I hope) how the top bellied forward toward the sound hole significantly (it was much worse before removal and flatten quite a bit after the bridge was removed) and the bridge lifted before it was removes. I think the combination of thicknesses and misplaced bridge plate cause premature bellying.

What say you?
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Tim Benware
johnnparchem
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Re: Re-topping

Post by johnnparchem »

I think the bridge plate position more than the thickness. It may have rotated on the change in stiffness between the end of the bridge plate and the overhang of the bridge, Most of the tension is right at the back of the bridge. Also if the wings of the bridge is where the lifting occurred than it was not tied to the xbrace and all bets are off.
Ben-Had
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Joined: Fri Sep 03, 2010 2:14 pm
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Re: Re-topping

Post by Ben-Had »

johnnparchem wrote:I think the bridge plate position more than the thickness. It may have rotated on the change in stiffness between the end of the bridge plate and the overhang of the bridge, Most of the tension is right at the back of the bridge. Also if the wings of the bridge is where the lifting occurred than it was not tied to the xbrace and all bets are off.
I agree more plate than thickness but the combo is why I saw it as a perfect storm. Here is the bridge location, I drilled holes on the outline of the top so you can see where it sat.

Edit: FYI this was forward shifted bracing on a "0" sized guitar.
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Tim Benware
Ben-Had
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Re: Re-topping

Post by Ben-Had »

Finish is on, leveled and buffed and the neck, bridge, PG and strings make it ready to go!
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Tim Benware
johnnparchem
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Re: Re-topping

Post by johnnparchem »

Wow that turned out nice. Good warranty work!
Ben-Had
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Joined: Fri Sep 03, 2010 2:14 pm
Location: Creedmoor, NC

Re: Re-topping

Post by Ben-Had »

johnnparchem wrote:Wow that turned out nice. Good warranty work!
Thanks John.
Tim Benware
nkwak
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Joined: Sat Nov 13, 2010 9:55 pm
Location: Pittsburgh PA suburbs

Re: Re-topping

Post by nkwak »

Wow!

Thanks for this! I've got an old beater in my basement that I've been wanting to try this out on.

Now regarding the bridge plate placement, was there an issue with the size of the bridge plate that you weren't able to account for because the main X brace was forward shifted? It occurs to me that a forward shifted X brace results in a wider are between the lower portion of the X brace where the bridge would sit. How did you address this this time? Did you have to make a wider bridge plate?
~ Neil
Ben-Had
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Joined: Fri Sep 03, 2010 2:14 pm
Location: Creedmoor, NC

Re: Re-topping

Post by Ben-Had »

nkwak wrote:Wow!

Thanks for this! I've got an old beater in my basement that I've been wanting to try this out on.

Now regarding the bridge plate placement, was there an issue with the size of the bridge plate that you weren't able to account for because the main X brace was forward shifted? It occurs to me that a forward shifted X brace results in a wider are between the lower portion of the X brace where the bridge would sit. How did you address this this time? Did you have to make a wider bridge plate?
Yes. When you shift the x-brace forward it widens the bridge plate. Just remember the bridge, of course, will remain in the same place so I locate the bridge and trace its location on the top, then I lay the bridge plate blank over the bridge tracing on the top, place the x-brace in position and trace the x-brace location on the bridge plate blank. That give you the oversized bridge blank shape, then I check it for correct fit and glue the bridge blank into place and locate all the other braces to the bridge plate.
Tim Benware
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