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On a Cedar top is there any relevant difference between using a Cedar bridge patch vs. a Spruce patch?

All else being equal - except the intrinsic property of Spruce being stiffer, if I normally use a .075 Spruce patch, wouldn't it be just as good going with perhaps a .085 Cedar patch?

The only reason I ask is I normally use the soundboard cutoff for the patches, but Spruce for the bracing. Wondering if anyone has any numbers or empiric data on spruce braces with cedar patches vs. all spruce (brace and patch).

Steve

I'd be hard pressed yet to say whether I could tell the difference between building with or without a bridge patch, much less +/- 0.01"
on a given patch.

In any case, you would certainly be dealing with variability between different wood samples. If you don't know your 'right' target stiffness, how would you tell what thicknessing to a given dimension was getting you?

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Jim Kirby
kirby@udel.edu

I could be wrong and am willing to stand to be corrected but I'd guess it don't matter how many you've built, the randomness of variables in the equation won't make a difference.

I'm told, Romanillos says he's built both ways and doesn't feel they make much of a difference in the sound. He chooses not to use them. However, he does not build Cedar topped guitars, either.

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

I use a rosewood patch (it's called the bridge...) <G>

you guys crack me up

you're right. As a complete noob (my teenage son say's that means rookie), it wouldn't notice or care one way or the other. But I'm am looking to increase my knowledge base.

As I build, I'm always looking for reasons why; why spruce for bracing on a cedar top? If for classical guitars the bridge patch is so important, why not a hardwood like rosewood (weight?); is the weight significant that it makes that much difference?

etc.

I'm making so many mistakes just starting out, that another won't make any difference - never touch woodworking tools before, let alone understand the "feel" of wood. But I want to do this for a long time and I value the experience you all have.

So thanks for indulging the Guitar Noob. I think I'll add that as my new signature.


Steve

I think many of us were saying that it is not particularly important. It does little to improve sound in a classical guitar, if anything. Weight is always an issue with a classical. The bridge gives all the bracing you need at that point. The only thing I can think of that it might do is to reduce, somewhat any propensity for the top to scallop along the brace lines at the point of the bridge.

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

One of the useful effects is to help keep the doming until the bridge is on, and help the actual bridge glue-up by reducing those scallops between the braces that Waddy mentions.
It is also useful if you bridge wood is particularly light or not stiff enough. This is not only the case with light bridge wood, but with very heavy wood as well which needs to be thinned a lot.

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Build log

I've decided to not even use one any more and I like it, saves me time and I believe the fan braces could loose strength when they are notched there even if done properly. The only convincing argument I have heard for having one is that it will help in times of stress due to shrinking and swelling of the top/bridge assembly from moisture changes. There's better ways to control that.

As a self professed new builder, the usual suggestion is to get a good plan and follow it, so if the plan you are using has a patch, then use one if it doesn't don't. In the beginning it is a good idea to assume that the plan, be it a Hauser or Torres will make a good guitar and has reasoning behind the design that the original builder developed during his career.

There is nothing wrong with having an enquiring mind, but the answers you get from more experienced builders who are trying to help you, should be taken as meant.

I don't use bridge patches at all on my Torres based guitars, if the finest builder of guitars of all time didn't, then I'm not going to argue with him.

As to why spruce for bracing and, if used, bridge patch is that it has the lowest weight to strength ratio and as Waddy said on a classical, with its low energy system, weight is a killer.

Personally I don't like cedar topped guitars either, but that is personal taste.

Colin

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

I make guitars for the sound my client wants to hear.
This includes bridge patches for some.
Especially cedar top Fan braced guitars.
Because of the reason Waddy has posted.
The scalloping .
I use a Marcelo Barbero Flamenco bracing and he uses a patch in the plan I have.
I've noticed a tighter treble with the patch-more free or open without it.
Mike

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Mike Collins

The bridge patch adds another glue line and makes the construction a little more like plywood in this area of the top. It probably does enhance the stability of the shape of the top some. Some designs extend it past the bridge wings, to decrease the likelyhood of cracks in that area, I have been told.
It's nice to have an idea what people's thoughts are behind these small items. It helps us decide how necessary they are and what importance we should attach to them.
Hauser used bridge patches, Torres didn't. They both made great guitars.