Re: [Harp-L] Question for all you Marine Band Customizers

This is why they leak... and what you can do...
Take the reedplates off and run your fingers over the comb, you'll be able to feel how they, besides being uneven, the comb gets thicker at the comb teeth. Combs have been made that way since the 1800s. Seydel, Hohner, everybody was doing it in 1900, about as far back as my personal experiences (of seeing harps from the periods) go on these things. 
Now I believe the idea back in the 1800s was that the comb and reedplate would touch near the mouth. When the wood soaked up moisture and swelled, it would want to take the path of least resistance, the top, already flush with the reedplate, would swell first and wedge itself between the reedplates. Now, as the middle of the comb tooth starts to swell, it pushes in all directions, the easiest path is to fill in that gap between the middle and the reedplate. It needs moisture to get tight. That's why guys used to soak them in beer (not recommended). 

On a Marine Band 1896, it's not extremely leaky, but when you get up to a 365 or even 364, this gap is magnified because the holes are deeper... and since the holes are bigger, the minute amount of time it takes to go from negative to positive air pressure in the hole, or vice versa as you play is increased. All this adds up to  a leaky harp. The answer is to flatsand and seal, it will be fine with the nails on. If you drilled it out for screws, you could make the screws hold with more force, which buckles the reedplate slightly and closes some of that gap. But that it is not optimum. Optimum is a perfectly flat comb with the reedplates snug, not tight, SNUG against them. 

Now if you flatsand, you've eliminated the swelling mitigation of the designers and your wood, with no place to go, will go up and you've got a worse cheesegrater than ever. But if you sand it, then seal it, you've taken care of this. 

Remember what I said about the larger chamber size affecting play? If you make the comb chamber smaller you can change that and make it more like an 1896, the way you do that is to flat sand it thinner. Keep in mind, if you go too thin, you can't add back on. But it will help. a lot.

I think you could get away with not sealing the entire comb. Probably 90 percent of moisture absorbed comes from the top of the comb tooth, especially if you put your tongue on it. I've seen prewar Seydels where Seydel only sealed the very top, where a tongue blockers tongue would be. Seydel still makes the Hochlandsklange this way. Putting sealant on just the top of the comb tooth (better if it's apart, so it doesn't run in on a reed) will reduce swelling. 

We think they didn't give a crap about comb swelling back in the day, but they did. There's all kinds of patents where they tried to overcome it. Mitigating comb swell was the holy grail back in the day. Seydel was sealing the top where your mouth goes on some, Hohner came up with this metal strip that ran all along the moisture-absorbing surfaces. Jason has one of those. I've seen the patent, it was one of those patents awarded to Matthias Hohner himself a few years following his death. 

I know I posted links to these earlier, but I'll put them in this email for the archives' benefit. Here's what needs done to the 365. When you flat sand it, you need to attach it to something that is not only flat, but will not bend. 
Flat sanding:

Sealing a comb (prewar Seydel Bandmaster), it's a 10-hole, but about the size of a 364)

Then lightly flat sand after the seal._________________________________
Dave Payne Sr. 
Elk River Harmonicas 

----- Original Message ----
From: Richard Hunter <turtlehill@xxxxxxxxxxxxx>
To: harp-l@xxxxxxxxxx
Sent: Saturday, November 15, 2008 1:35:21 PM
Subject: Re: [Harp-L] Question for all you Marine Band Customizers

I own 3 model 365s in different keys, all set up in SBS tuning.  Out of the box, all three of them were leaky as hell--practically unplayable, in fact.  I found this quite distressing, because I think the basic setup of these harps is fabulous. Big low end, high register up in the clouds. You can do a lot with one of those harps--when it's working, that is.  (I'm pretty sure Jelly Roll Johnson is playing one on one or more of the cuts on his most recent CD.)  

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