Official Luthiers Forum!

There seem to be a few makers using double tops on their guitars..either using nomex or some kind of arrangement where the 2 surfaces are separated by thin strips of wood.
My question is this,will a double top "Age"."open up","mature" like a single top made from solid timber?
The reason I ma asking is that surely a double top is a laminated design...and they (lamintaed tops) don't "age/open up/mature.
If they don't get better with age..is that because they are meant to sound their best from the word go..until forever!!
any one want to comment?

I would guess they will a little, but less than a solid top.

Improvements with age are supposed to be due to a process called "sublimation" where some of the solid top is converted directly to gas due to the vibrations from the strings. This loss in mass (without a loss in strength) is supposed to be what causes the phenomenon.
Sounds insane I know!

The nomex tops from what I understand have very little material in them at all, meaning less for this process of sublimation to occur on.

I could be wrong here but I have always felt that sublimation was only a part of the equation. As wood ages its resins harden with age. I would guess sublimation plays apart in this process, but back to my point I have rightly or wrongly always assumed that the crystallizing of the resins also played a part in the change of tone of an instrument over time

As woods cells get older they shrink a tiny bit with every bit of moisture lost!
This makes them smaller and eventually makes the cell case (so to speak) harden!
That's why wood gets lithe in weight as it ages !
I would supect the double tops would benifit from the process just like any other top!
After all they are top sandwich!!!

Mike

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Mike Collins

In that case why aren't 2 pieces of solid wood glued together (plywood) also "top sandwich"?
I am really interested as to why a double top ages but plywood (2 layers) apparently does not.

Plywood!
opposing grain with each layer !

This is not PLYWOOD!
The grain is positioned in the same direction !!
The two are glued to each other under the F.B & on the outside edges -but have a layer of Nomex between them in the lower bout!
All woods lose moisture over age-unless salt dried!
This hardens the cells !
Then the wood is lighter in weight-so it responds quicker & with more volume -etc....
Mike

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Mike Collins

I went to the seminar on double tops by Charles Fox (Healdsburg 'o5) and was under the impression the entire nomex core was glued.. Maybe I missed something but he was using what looked like an ink roller and glueing the whole core? The roller kept the layer of glue super thin & consistent. The bridge patch was to add additional surface area where the top would be stressed the most and prevent the strings from pulling the bridge and top apart.

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CVT Inc.
A tour of our shop (Somewhat outdated)
My Personal eBay profile. BCWoodBug

Ah I think I misread what you were saying there Mike..

never mind

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CVT Inc.
A tour of our shop (Somewhat outdated)
My Personal eBay profile. BCWoodBug

[chemist hat]
Sublimation is indeed the direct conversion of solid to gas (think dry ice) - but there's absolutely no way this happens with wood. At the molecular level, about the most that can happen is the cellulose can break down into simpler compounds, but its not evaporating - the vapor pressure of dry cellulose is practically nil. And after all, you have trapped it underneath a finish!
[/chemist hat]

My understanding is that this "opening up" is nothing more than the gradual breakdown of the wood structure at a fiber to cellular level due to vibration. You might expect the same to happen with a double top - Nomex is basically an impregnated paper.

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The member formerly known as erikbojerik....

Easy dude..it was only a genuine question.
Anyone can use exclamation marks..look !!!!!!!!.........easy

If sublimation was a factor, we'd be putting tops in wind tunnels instead of 'playing them in'. That one's a pseudoscience fantasy.
edit: And it looks like Mr Hauri beat me to that one

So far as the cellular collapse...that theory's why people are fond of baking tops now. If you bake 'em then the cellular collapse has happened before the top's even on the guitar in all three cases. In a 'plywood top' there's a lot of resin/glue content and so the effect will be lessened. In a double top or a solid top, there's very little non-wood content.

I don't think cell water-carrying capacity is the main factor at all, actually.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Double tops definitely age.

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Jim Watts
http://jameswattsguitars.com

Hemicellulose sublimates.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Basslord, whoever you are, Mike is a longtime regular here, and he always writes with a lot of exclamation points. That's his style. He wasn't over-reacting to your particular post. Mike is also a very experienced and very good guitar maker. I would suggest thanking him graciously for his input, rather than condescending to him. If I were Mike, I'd never reply to another one of your questions. But Mike is probably a better man than me.

What the ______ is your real name, anyway?

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Thanks Todd.
I'll keep the !! out as much as I can.

I use them when I think a bit of info is important.

Sorry -basslord !
Mike

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Mike Collins

Somewhat OT - but I beg to differ. Hemicellulose is nothing more than complex sugars contained within the dried cells; it might break down and dehydrate, but I find it highly unlikely thyat you have these big non-volatile molecules emerging from the wood. Yeah everything has a vapor pressure, but some vapor pressures are so small as to be negligible.

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The member formerly known as erikbojerik....

My apologies too Mike.

As a new comer to this forum I do not know the individual writing styles of each contributor.
and as we all know it is difficult to get a sense of the true meaning of sentences when emailing. If I came across as condescending it is only because I thought that I was being treated that way.
I have apologised for any unintentional offence.
As for you I don't care one way or the other if you reply to one of my questions.

Aw, Mike! I like your exclamation points! To me, they convey enthusiasm, passion, verve! Don't change, man! (I mean it. I'm not being the slightest bit sarcastic.)

...And you are certainly a better man than me for apologizing to basslord!

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

basslord ;
Are you a bass player,bass maker, or a bass fisherman?

This is a helping place-we all strive to learn & make better instruments.
The sharing of info here is second to none!!!!!!!!!

Todd is an experienced maker & repairman!
Insulting him is a slap in the face for all of us!!!
His input here is filled with real knowledge from years of instrument work. !!!

Mike !!!!!!!!!!!!
sorry Lance !!
for mouthing off!

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Mike Collins

Mike, my temper flared when I felt that you'd been insulted, but I'm afraid some of my angry comments have fanned the flames more than helped the situation. Now, I feel like I'm partly responsible for getting you riled up. I'd say we'd better both just cool our heads get back to the shop. This ain't worth the fuss.

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/