Official Luthiers Forum!

I am looking at buying a supply of either Sitka or Engelmann woods for kerfing, bracing and front and tail block. What would be the difference in structure and what would be the difference in tone between using these woods. The wood for the tops that I have is Sitka and the bodies will be either Indian Rosewood or Mahogany. Iam wondering about strength difference and tone differences again using either Sktka or Engelmann inside the guitar.

Also, if I make the bottom braces from one of the two woods I am guessing I should use the same wood for the top bracing correct?

Thanks,
Chuck

For kerfed linings and blocks I don't think it will make any difference what kind of spruce you use as long as it is dry- you could use mahogany or other species as well.
For top bracing you should get lots of opinions here . Spruce would be my recommendation.

There's no need to use the same wood for both top and back bracing - lots of builders use mahogany or Spanish cedar for back bracing, though spruce works well also.

Cheers
John

Dude, when it comes to bracing, spruce is spruce and thats about the size of it.

However if your into the ultimate spruce bracing, me do has some rather rair Mongolian spruce that was harvested from the Gobi desert. It was used for the support beams in Ganghis Kans' yurt and has been remilled. This stuff is over 800 years old and stiff like Viagra. Tops are $800 and braceing wood is only $200 bucks.

Dude, Go score a 2x6 of spruce from the lumber yard for $5 bucks and you gonna has enough bracing for a few builds. Cheap like borsch too. Of course if you are a conosure and want the very best of the best, well then pm me and we talk about the Mongolian spruce.


blessings
Padma

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Audiences and dispensations on Thursdays ~ by appointment only.


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Sitka & LUTZ are tough woods!
They both will work for blocks.
Any wood will work for linings!
I like denser woods -Mahogany etc. for linings !
Helps with the side to top stiffness a bit !

Engelmann is a great wood for instuments
IF you can get pieces without RUNOUT !

Get some LUTZ from Shane at Highmountain !
It''s really the best !


Mike

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Mike Collins

Hey Mike, stop yelling!
My friend says adi is best,
but I'm with the Padma on this one, spruce is spruce.
A top plate you might notice a diff,
but I probably couldn't.
Some day I wanna find me a spruce log, long enough for weiss tops, and split and process them meself.

Spruce may be Spruce but I can tell you from my testing that it's possible for any species to have a 2X spread in stiffness. You need to be selective about brace wood in my opinion, and I not talking about variety.

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Jim Watts
http://jameswattsguitars.com

Look at it this way: the top itself for a steel string will weigh something like 150-180 grams. The bracing, all of it, will weigh maybe 30-50. Saving 10% of the brace weight will reduce the overall mass of the top by a couple of percent, and most of that saving will be in the upper cross brace and the upper ends of the X that don't move much anyway. I'm not saying that the brace wood isn't a factor in the sound; everything is. It's just not the _main_ factor, and certainly the mass of the bracing is less of an issue than the toughness and resistance to creep. IMO it's much more important to have some method of optimizing the function of the bracing on the top, such as deflection measurements, tap tones, or Chladni patterns.

I'm very much in the camp that feels that 'spruce is spruce'. If you use a low-density piece and make the bracing a little taller to make up for the overall lower Young's modulus, you'll save a little weight, but not much. I would use spruce though, simply because it tends to be tougher (harder to break) than cedar, redwood, or Doug fir.

Thanks Alan. Are you sure about the Douglas Fir though? I've never used it for guitars, but anytime I've used it for other things, it sure seems like tough stuff, almost more like a hardwood in some cases. Impossible to drive a nail into some of the old stuff I've had.

Hey Darrel, I not Alan but I thought I should just add that by "tough" Alan is referring to the tenacity of Spruce. D-Fir tends to be a lot more brittle than spruce so will break under less deflection than spruce. The thing that makes spruce so good for instruments is the LOOOONG fibre that spruce has. This allows it to remain intact while thin and under fairly significant loads yet still be light in weight. But you are right, D-Fir has about the same specific gravity as Honduras Mahogany if I remember correctly.

Shane

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Canada

Thanks for that Shane.

The meanings of 'less' and 'more' tough here depend on whether you are comparing beams of the same size or same weight, I think.
Stiffness (Youngs modulus) and fracture toughness are different things but, as Alan has pointed out previously, the stiffness and density of softwoods track together. So, a DF beam will be stiffer than one of Sitka spruce if they are the same dimensions (Youngs Modulus about 25% higher for DF, density about 20% higher).

I wouldn't consider using DF for most of the bracing in a guitar, but I have used it a few times when I wanted to immobilize the 'end-of-fingerboard' area and didn't care much about the weight. I'd probably use spruce there, were I to do it again.

I've had some DF that was very sinewy and tough, while other samples had along-the-grain flaws that made it very splintery. That's the fun of woodworking!

Cheers
John

All the Doug that I've ever used tended to be really splitty, with low shock resistance. Spruce is much better that way, and that's what I mean by 'tougher'.