[Harp-L] comb swellify factor (was MB-D comb swelling) and probably more than you wanted on wood comb swellification

[David Payne <dave@xxxxxxxxxxxxxxxxxxxxxx>]

Here's my take on why some combs swell more than others.

I remember once I was over at a plastic-comb guy's house and he was dissin' the wood, saying it swelled. I was explaining about when you sealed wood, that wasn't an issue, but wasn't getting far...  I had a Marine Band I had made a mahogany comb for and beeswaxed. As far as playing, it was dry as a bone. 
So what I did, he was dissin' the wood, I asked for a glass of water. I chunked the harp in it and started talking about something else. 
I'm talking and he keeps looking at me, then looking at the glass, looking at me, looking at the glass, after a couple minutes, he starts figiting, after three minutes or so, he yells "are you crazy!?" 
I pulled the harp out, tapped out the water, played it and showed him the comb teeth. They were fine. BUT, about an hour later it started to swell, not extreme, but it was noticeable... it unswelled, but very slowly. I learned then that even the best sealed combs are slightly permeable to water.
However, the factory sealants I've seen have been sufficient for playing... mind you, I've never had an MB DeLuxe, so I don't know its sealant specifics. The factory sealings I have experience with are from Hering and Seydel.
Besides the thickness and types of sealant applied at the factories, there's another factor at work, the wood underneath. The swellify factor, for instance, is a greater issue with pearwood than it is with beech. On the Payne Swellify Scale of 1-10 (10=swelliest, 1=impunity to swelling) Pearwood is 9, Beech 6, mahogany 5.5, maple is 3, black walnut 2.  The denser a wood is, the less places there are for water to go inside.  
So, even if the amount of moisture permeating into the wood is equal, pearwood would be more prone to swelling than other woods, as illustrated by the Payne Swellify Scale.
There is yet another factor at work... WHERE in the tree the wood came from. Let's say your comb is cut from total sapwood it's swellification factor will be 9 Paynes. You cut a comb from the heartwood of the same tree and it will now register a mere 8.2 Paynes. 
So, even if all other factors are the same, there is a variance in the wood... the heartwood is in the center and its job is to be dense and keep the tree from falling over. Sapwood is the next layer out from the center. In the living tree, sapwood is designed by providence to soak up water. It acts as a sponge that soaks water from the earth, the cambium cell layer (the only part of the tree that grows) is on the outside of that and drinks from the sapwood sponge, as do the leaves. It transports water by diffusion, just like a sponge. As the tree grows, the sapwood becomes heartwood, it quits soaking up water and starts holding the tree up. In some trees, like Osage orange and cedar, it even changed color as it becomes heartwood.
It's a two-edged sword, when you seal a comb with a Payne swellify factor of 9, it takes a lot of sealant, more sealant is soaked into the wood instead of curing on the surface. At Payne swellify factor 6, the surface is better sealed with the same amount of sealant, plus the wood underneath is less permeable to what moisture gets through.
On diatonic combs I can not tell, but on chromatics it's pretty easy on Seydels, at least, because of how the combs are cut, the grains run vertically. When you sand off the outside finish of a Seydel chromatic, it's like looking at a tree stump, although grain is not very visible on pearwood. I've not been able to get a read on the 270s, they don't look like a tree stump on the bottom when you sand them down. Both Seydel and 270s are pearwood, but they have different properties.
I know from cutting out wood to mount external slide springs flush, there is most definite  difference in density there. Some I've chiseled out have been like butter. Others have felt more like oak as I chiseled. The Seydel chromatic combs have been pretty hard.
As we know, pearwood trees aren't anywhere near as tall as maple trees. Thus, the difference between pearwood heartwood and sapwood is not as pronouced on pear, but there is a difference. 

Dave
____________________________
Dave Payne Sr. 
Elk River Harmonicas
www.elkriverharmonicas.com 


----- Original Message ----
From: ChappyOnIce <chappyonice@xxxxxxxxxxx>
To: harp-l@xxxxxxxxxx
Sent: Saturday, October 4, 2008 11:59:16 AM
Subject: [Harp-L] Re: Fallacy of "Playing Wet" (was MB-D comb swelling)

I'll vouch...I've had my MB Deluxe swell as I am learning overblows.
Right at the 4, 5, and 6 holes it's swelling after an hour or so of
practice.  Though I would say it may be uncommon just because I'm
strictly working overblows so I'm blowing a lot of air (and
condensation) into the harp in those spots.  Normally and hour of
practice would not swell my MB Deluxe.

On Oct 2, 4:34 am, Will duFauve <harpgu...@xxxxxxxxx> wrote:
> Gee, guys. I guess some of you weren't around 2 or 3 years ago when people were discussing the MB Deluxe comb, and offering remedies like lacquering the insides with Hard-As-Nails nail polish top coat.....I only asked what is current re: varnishing them, should I use the Behlin's salad bowl finish, etc. That's not a cue to go off on "you play too wet, you play too hard, do you soak them, it never happens to me, do you sleep with them in your mouth 24/7.
>
> Thanks for the put-downs. And, what's with all the private emails trying to sell me something? Your parents never taught you any social graces, like starting out saying "Hey, Bud. How's it goin'? Nice day?" like I'm a fellow in the brotherhood of musicians, and then try and sell me something?
>
> I will now explain the fallacy of playing "wet." All harmonica playing is played wet. Moisture is unavoidable. You put them in your mouth and exhale. The wetness proof? 1) go outside and exhale into the air on any cool day. See your breathe? Water condensation. 2) Cup it like a bullet mic and breathe into a clear drinking glass. See condensed water coat the glass in only one or two breathes? 3) Play any harp for a few minutes, disassemble it, and observe all the little condensed water droplets on the reeds, reed plates, covers and comb.
>
> Is this water (proofs 1 thrugh3) saliva from poor technique and "playing wet?" No! It is condensed moisture from your exhaled breathe. You never accidently gapped a low reed just a hair too tight, so the harp played great for the first 3 minutes untill the condensation made the reed stick and you had to go in and open the gap a little more to get it to vibrate under the weight of the condensation?
>
> When you exhale thru a harp you make the innards very wet simply by breathing into it. If you play that harp for a half hour, it stays wet for (more than) a half hour and much of that condensation will be absorbed into an unsealed wood comb, I don't care how good your driest technique is. I doubt there's very few uninformed newbies anymore who think you break-in a harp by soaking it in a glass of beer, and they're not usually buying MB-Deluxe's a dozen at a time at $53 a pop.
>
> For the guy who said he only plays single notes, no tongue blocking, or split octaves, etc., you probably need to give up keeping your instruments dry in favor of developing some fat wet tone. I think I'll sparingly use the Behlin's on the bare wood innards of the combs, and leave the factory finish intact. That should work.
>
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