Weak Cedar Top

[smatel]

Let me first apologize for restating this question, which I originally posted yesterday. Also, please blame my weak social skills for my barging in on your venerable group uninvited, and thank you for the help I may get from you!

 

I have a guitar (Lowden F25C) with a cedar top and a br, pin through bridge. The bridge has pulled away from the top for the second time. The first time I took it to a luthier in Milwaukee. He re-glued the bridge and I was set for a couple of years. I called the luthier yesterday and he says he sees this from time to time; pin through bridged pulled off cedar tops. Couldn't suggest any real fix except to reduce string tension or reinforce the bridge/bridgeplate connection with a couple of screws. I'm already using light strings and I thought to tune the instrument down a half step. Not my first choice.

 

So what about the screws? Have any of you luthier types seen this and what would your suggestions be.

 

Thanks to FreemanKeller who got me started yesterday.

[Queequeg]

You needn't aplogize for being here.

We welcome you to the HCAG forum, smatel!

Since this is the second time this has happened, I think I would contact George Lowden for his recommendation.

 

To contact Lowden Guitars:

 

+44 (0)28 44 619161

or

info@georgelowden.com

[Freeman Keller]

I second the suggestion to call Lowden. They might fix it under warranty. Many classical guitars have both pinless bridges (I assume that is what you are talking about) and cedar tops and you don't hear of the bridges pulling off (they are under a lot less tension, however). But a properly done glue joint should be stronger that the parent wood - if you try to split it you should tear fibers out of both sides.

 

The only time I have heard of screws through the bridge is to repair something like a badly damaged laminated top or for a JLD or something like that. I would do it to a fine guitar only as a last resort.

 

And last, but far from least, welcome to HC and please ask this sort of question an time - its the ones about ethics or snow shoveling that we don't like

[JasmineTea]

Sounds like something went wrong with the glueing of the bridge...twice.

 

I'd try having it glued again, only make sure there is'nt any residual chemicals, oils, or whatnot left on the cedar top, or the bottem of the bridge.

 

You might also consider having a pin bridge made. With pins, the string pulls on the top from inside the guitar. The Lowden pinless bridge is pulling the bridge straight towards the soundhole, pin bridges are actualy rotating the plate and bridge towards the soundhole.

[JasmineTea]

Many classical guitars have both pinless bridges (I assume that is what you are talking about)

It's a steel string.

[smatel]

Thanks for the replies. You guys sound like you know what you're talking about!

 

When I inspected the damage I noticed wood fibers on both sides. The force seems to have torn the fibers along the grain and there is not much glue visible. This condition is consistent with the findings of the inspection of the first separation, two years ago. My conclusion is that the wood is weaker than the glue.

 

I thought of converting it to a pin bridge, as JasmineTea suggested. My hesitation comes from not really understanding the difference between the architecture of a top/bracing pattern designed to support a pinless bridge and one designed to support a pin bridge. I seems like at the very least I may change the responsiveness of the guitar. What am I looking at here?

 

On the theory that the bridge plate, top, and bridge are, for all intents and purposes, a unit, how much harm could it cause to fasten the bridge to the bridge plate using glue and "something else?"

[smatel]

 

It's a steel string.

 

 

JT knows the instrument.

[JasmineTea]

I think I'd go with a different type of bridge, or re-glueing the old bridge again before I'd run any screws into it. Reason being, if the glue/wood gives a third time, all that's going to be holding it on would be the screws, which would eventualy rip throught the top making a bigger problem.

 

I'd thought about the "architecture" thing when I first posted, and although the git was not designed for a pin bridge, I don't see any other option.

 

Call Lowden.

[Dan Hall]

 

On the theory that the bridge plate, top, and bridge are, for all intents and purposes, a unit, how much harm could it cause to fasten the bridge to the bridge plate using glue and "something else?"

 

I sure don't know for certain but my instincts and my limited knowledge of fasteners tell me that if it's pulling the wood apart it will pull the fasteners through the top.

 

Are there any other factors? Moisture? Temperature extremes? Cycling between highs and lows of either?

 

Oh, and welcome. This is a wonderful place full of great people. Sometimes we just don't notice the new post or two.

[JasmineTea]

Also, if you had a luthier make a pin bridge for it, he'd probly make a new plate for it as well. The combination of plate and bridge, and that the strings would instead be pulling from inside the guitar would, I think, keep it from coming off again.

 

I'm not a luthier though.

[smatel]

 

Also, if you had a luthier make a pin bridge for it, he'd probly make a new plate for it as well. The combination of plate and bridge, and that the strings would instead be pulling from inside the guitar would, I think, keep it from coming off again. I'm not a luthier though.

 

 

That's a cogent suggestion. I think that after I contact Mr. Lowden, and depending on what he tells me, I will talk to the local luthier.

 

Thanks

[smatel]

 

I sure don't know for certain but my instincts and my limited knowledge of fasteners tell me that if it's pulling the wood apart it will pull the fasteners through the top. Are there any other factors? Moisture? Temperature extremes? Cycling between highs and lows of either? Oh, and welcome. This is a wonderful place full of great people. Sometimes we just don't notice the new post or two.

 

 

No real extreems except maybe RH. We're experiencing a cold snap, here in the midwest, and It's tough to keep the RH up. I did, however, mention this to the luthier in Milwaukee and he believes temperature changes would be more likely a culprit than humidity changes. Of course he's the one that repaired it in the first place, so despite his stellar reputation, I'm tempted to take what he tells me with a grain of salt.

[Freeman Keller]

A couple of thoughts, guys. First, I was pretty sure it was a pinless bridge but wanted to confirm that (first post says "a br, pin through bridge"). Second, I was pretty sure it wasn't a nylon string (altho Lowden makes 'em) but wanted to say that pinless bridges are common on cedar topped classical and they don't pull off. I know it was kind of confusing.

 

The whole idea of making it a pin type bridge scares me - pinless bridges have a much lower break angle (which implie to me less rocking force on the bridge which implied to me possibley lighter bracing. You would have to add an bridge plate - not impossible but not trivial either. You would most certainly void any consideration of Lowden ever supporting this. Here is a pic inside one Lowden - no idea if it resembles this one.

 

http://www.frets.com/FRETSPages/Musician/Guitar/XGallery/XGalleryViews/lowden.jpg

 

Good luck and let us know what Lowden says

[Dave W.]

Since the bridge is pulling bits of cedar top off, which is what a good glue joint should do, I wonder if you have a weak piece of cedar, or maybe one with a weak area. I think Lowden's advice is the right place to start, a pretty serious guitar maker. Is it under warranty?

[Hudman]

You got some great advice. I think JT is on the money about making sure the surface of the bridge plate and the contact surface on the guitar are perfectly clean and free of glue and wood residue.

 

Here's how I would fix it based on your description of the damage:

 

Sand down the bottom of the bridge and sand the contact area on the cedar top (tape off the area surrounding it). I would apply a light coat of wood filler over the shredded area, let it dry and sand it to insure the bridge contact surface area is level. I would glue the bridge down with a high quality wood glue like this: http://www.lmii.com/CartTwo/thirdproducts.asp?CategoryName=Adhesives&NameProdHeader=Instrument+makers+glue

 

Without looking at it, it sounds like your luthier failed to properly prep the contact area befor regluing the bridge. Glue will fail nine times out of ten if the contact area is not clean and level.

[smatel]

 

Since the bridge is pulling bits of cedar top off, which is what a good glue joint should do, I wonder if you have a weak piece of cedar, or maybe one with a weak area. I think Lowden's advice is the right place to start, a pretty serious guitar maker. Is it under warranty?

 

 

Probably no warranty. I bought it used from a "reputable" instrument retailer in Madison, WI, which claimed the guitar had been traded for an O10, by a guy who had bought the F25C just over 30 days before.

 

I will write Lowden anyway. You never know...

[smatel]

 

You got some great advice. I think JT is on the money about making sure the surface of the bridge plate and the contact surface on the guitar are perfectly clean and free of glue and wood residue. Here's how I would fix it based on your description of the damage: Sand down the bottom of the bridge and sand the contact area on the cedar top (tape of the area surrounding it). I would apply a light coat of wood filler over the shredded area, let it dry and sand it to insure the bridge contact surface area is level. I would glue the bridge down with a high quality wood glue like this: http://www.lmii.com/CartTwo/thirdproducts.asp?CategoryName=Adhesives&NameProdHeader=Instrument+makers+glue Without looking at it, it sounds like you luthier failed to properly prep the contact area befor regluing the bridge. Glue will fail nine times out of ten if the contact areas are not clean and level.

 

 

 

 

What type of wood filler, assuming there are different kinds. Can we expect the wood filler to make at least as good a bond with the cedar as the glue?

[Freeman Keller]

If I were going to do it, I would clean it of every bit of residue, sand both parts, use no filler, and glue it with hide (1st choice) or AR (yellow glue, tight bond or LMI's stuff). Build two very good clamping cauls - one that fits inside the X brace and one the exact shape of the bridge (or use one of the fancy bridge clamping jig thingies) with at least 3 deep c-clamps. Of course alignment must be perfect (with a capital P)

 

This is a pin type bridge on a spruce top (which makes alignment easy 'cause you can use the old pin holes) but here is the proceedure.

 

http://www.frets.com/FRETSPages/Luthier/Technique/Guitar/Bridges/ReglueBr/regluebr1.html

[Hudman]

 

What type of wood filler, assuming there are different kinds. Can we expect the wood filler to make at least as good a bond with the cedar as the glue?

 

 

I've heard of luthiers using epoxy based fillers like this: http://www.lmii.com/CartTwo/thirdproducts.asp?CategoryName=Filler&NameProdHeader=Z%2Dpoxy

[smatel]

 

If I were going to do it, I would clean it of every bit of residue, sand both parts, use no filler, and glue it with hide (1st choice) or AR (yellow glue, tight bond or LMI's stuff). Build two very good clamping cauls - one that fits inside the X brace and one the exact shape of the bridge (or use one of the fancy bridge clamping jig thingies) with at least 3 deep c-clamps. Of course alignment must be perfect (with a capital P) This is a pin type bridge on a spruce top (which makes alignment easy 'cause you can use the old pin holes) but here is the proceedure. http://www.frets.com/FRETSPages/Luthier/Technique/Guitar/Bridges/ReglueBr/regluebr1.html

 

 

Wow! Thanks for the detail. I really need to understand things and this surely contributes to that end.

[smatel]

If I'd known how gracious you guy are I'd have interacted with you much sooner. Thank you!

[bjorn-fjord]

Sorry to hear about the problems with your guitar. A relative of mine (who is one hell of a great player http://www.andysheppard.com/) owns a Lowden cedar top with a pinless bridge and his story is exactly the same as yours. His bridge is pullling up for the second time.

 

You've gotten some good advice here and the only thing I would add is that guitars with pinless bridges generally have the same type of bridge plate as pinned bridge guitars so converting your guitar should not be a problem. As a luthier, this is the direction I would take. However there is a slight chance that there may be a conflict between the placement of a pin hole and a soundboard brace. This would have to be determined before any major surgery was contemplated.

 

The bridge plate performs more a more critical function than simply protecting the soundboard from the string ball-ends. It stiffens the area of the soundboard that is under the most torsional force from the pull of the strings. A steel string guitar without a bridge plate would not survive very long.

 

Now, I don't mean to take your misfortune as an opportunity to be smug, but I can't help but notice the absence on this thread of any of the forumites who have flamed me in the past when I expressed my concerns about cedar steel strings and pinless bridges.

[telelurker]

Talking to George Lowden is a must - Lowdens have significant constructional differences from other guitars. You can be confident of a courteous and helpful response. Lowden's literature states that at less than 40% relative humidity there is a risk of the bridge pulling off, so that might be a contributory factor.

[Cripes]

Okay. This is all interesting. I have a pinless bridge on a Breedlove with Cedar top. Doomed?

[Freeman Keller]

 

Okay. This is all interesting. I have a pinless bridge on a Breedlove with Cedar top. Doomed?

 

 

 

Breedloves have a JLD which is almost always bolted thru the top. So I would think not. Which returns us to Smate's original question - I guess this would be an example of a pinless bridge on a cedar top WITh a bolt or two.

 

And Bjorn, thanks for the comments