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Greetings
I've had two bridges partially separate early in the life of the instrument (first several months) on guitars with Lutz tops. I've only built about five with Lutz so that's a pretty high percentage. I'm about to re-glue one and the other has been fine for a year in the hands of a professional player since it was re-glued. One was hide, the other LMI white. I've built 30 sitka instruments and had no problems in any of those. Anyone else had this experience? The bridges were radiused to the top and had good squeeze out all around.
Terry

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It's not what you don't know that hurts you, it's what you do know that's wrong.

Terence,
my third guitar was Lutz and the bridge is still on with full tension on the strings and after all this time I see no sign of lifting at all. It was glued on with Titebond. I also built another one glued with LMI white and no issues either. Were your bridges made from the same piece of lumber?

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Peter M.
Cornerstone Guitars
http://www.cornerstoneukes.com

Terry...I have three BRW bridges glued to Lutz with HHG. Two 1" wide pyramid bridges @ 25.4"scale with light strings...after 3 years. One 12 string belly bridge @ 24.9" scale... after 6 months.

No sign of separation and no apparent difference from other spruce species.

What wood was used for your bridges?

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JJ
Napa, CA
http://www.DonohueGuitars.com

Terence,

It's very doubtful if the top material is the culprit. Lutz is a wonderful tonewood and it's gluing properties I would guess are just like any other spruce. I've made about 15 Lutz topped guitars and I love the stuff. A couple of things could be occurring. There's always a possiblity of a bad batch of glue in the case of the LMI white, or a bad mix in the case of the hide glue. Another thing to take note of is when you removed the bridges, what was the condition of the bottom of the bridge and the top? Usually this will tell you what the problem was. If there were spruce slivers still on the bridge, look to see if there is an square termination anywhere on the perimeter of the bridge. This could indicate that when you scored the finish and scraped off the lacquer, the score was too deep and broke the fibers of the top at the perimeter and the bridge tension lifted the fibers at the score line. (If you taped the bridge area or used some method that doesn't involve scoring the finish, obviously this wouldn't apply.) If there is little or no glue residue on the top, it may indicate that all the lacquer didn't get removed prior to gluing.

Without knowing your usual prep/gluing/clamping procedure, it's difficult to pinpoint a specific cause, but with 30 guitars under your belt and no other failures, it's not likely a process problem. We all have these kinds of unexplainable things happen from time to time, I sometimes feel like I'm a forensic luthier, trying to reverse diagnose issues like this. It just goes with the territory.

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Jimmy Caldwell
http://www.caldwellguitars.com

sorry, double post

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Jimmy Caldwell
http://www.caldwellguitars.com

Thanks guys. Good to know that you have not had any problems with Lutz. The one with LMI white was a Martin type belly bridge and I figured it was a glue issue. The hide one was a pyramid on a 4 month old parlor which just came in so it's not removed yet. I'll let you know what I found.
Thanks
Terry

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It's not what you don't know that hurts you, it's what you do know that's wrong.

I agree with Jimmy;
prep. of the two glue sufaces and the condition of the glue is very important.
Make sure the bottom of the bridge is not rounded front to back.
It must be flat.

Was there any top fibers still glued to the bottom of the bridges?
I've never had a bridge lift on one of my guitars,even the cedar top ones.
Lutz is a tenacious wood,great for guitars .

Mike

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Mike Collins

one thing not noted was pressure. You can over tighten a clamp and glue starve a joint. I personally will mask off the bridge area or route the area so I know I have clean wood surfaces. The slightest amount of finish or sealer will not allow the glue to do its job.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

I have been routing off my finishes for a long time now and usually cut a shallow ledge in the edge of the bridge to clear the rim of finish. I'm sold on that method. I may have been guilty of over clamping however.
TJK

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It's not what you don't know that hurts you, it's what you do know that's wrong.

I removed the latest bridge, a pyramid glued with hide with the treble wing lifting. The wing that came up looked like it hung up on a chip of finish. There was very little glue under it. My fault. It's fixed now.
Terry

_________________
It's not what you don't know that hurts you, it's what you do know that's wrong.

SUCCESS

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it