Re: [Harp-L] was XB-40 bending, now making plastic combs tighter with silicone

[David Payne <dave@xxxxxxxxxxxxxxxxxxxxxx>]

Zombor is dead on with this. Kitt Gamble turned me on to non-toxic aquarium silicone. The problem with those hollow plastic combs is there is a very small area of comb that sits against reedplate. It's just a little line. Reedplates are stamped out, so they are never perfectly flat. They have slight undulations. Now on a flat wood comb, if you have an undualtion, it's no big deal cause it redolates (just made that word up) by the time you get to anywhere air can leak to.... but on a plastic comb, air can leak inside the comb itself.
So silicone stops this.. You don't necessarily need a syringe or anything fancy. Your finger will do. What you are doing is basically smearing a VERY THIN coat of silicone on the comb surface - that very thin line of plastic - at the edge of the hole where it meets reedplate. I put a very small amount on the comb, then wipe it off very lightly with a finger - it takes just the right amount off, a rag takes off too much, a scraper or knife isn't consistent enough - then take a scraper and scrape off excess on the sides.
 
There's a lot more to the bluesified Concerto than yanking off the appropriate valves. The harmonica shouldn't really work like it does, there's a major balance of stuff that has to be redone for the blues side to respond and bend by itself, yet the two sides respond in unison when the full two-harp octave chord is played without one side lagging slow or weak in the full chord.. I guess I'm revealing a little trade secret here, but non-toxic aquarium silicone plays a big role in making that possible It's applied in some places, but not others. controlling those leaks plays a role in balancing out the two sides... that, the valve arrangement, the gap setup and where the silicone is applied makes it work like its supposed to.   
Less is most definitely more when applying silicone. I use so little because when you use too much it gets on the blow reeds and the Concerto is pretty tight inside the holes, since there's four reeds (in groups of two) in each hole.  Right before I put the reedplates back on, it doesn't really look like there's silicone on the comb at all, that thin comb wall just looks kind of shiny. Besides chromatics, the Bluesified Concerto is the only thing I use silicone on. 



David Payne
http://www.elkriverharmonicas.com/


Elk River Harmonicas Forum now available via Iphone app, www.elkriverharmonicas.com/forum


________________________________
 From: Zombor Kovacs <zrkovacs@xxxxxxxxx>
To: "harp-l@xxxxxxxxxx" <harp-l@xxxxxxxxxx> 
Sent: Saturday, June 16, 2012 3:50 AM
Subject: Re: [Harp-L] XB-40 bending
  
Hi,

Yes, I have a tip. When I bought my XB-s I had to realize that the factory airtightness was poor. I sealed all my harps with silicone. I do not recommend anybody to do this (you can mess up reeds), because it was a very delicate job what I did with a syringe of silicone and a dispensing needle. But the result was close to dramatic together with some regapping and embossing. The response could not remotely be compared to factory response. What I can still recommend is regapping, some embossing and SEALING with silicone grease or a similar non curing agent. Even silicone grease or similar could get into reed gaps if you are not careful and temporarily block reed action (even for a longer time since it gets out of the gap slowly). But if somebody feels he is clever enough to do an all round sealing with the above mentioned method, he can expect some good results. I sealed the combs between the reedplates. If you don't want to actually get it
 bonded
together, you should apply some release agent to the reedplate (it can be either grease or real release agent). However I warn you again that you need special equipment. Professional adhesive dispensing needles, a syringe and choose the right viscosity silicone (not too low). Seal the mouthpiece as well. 
The problem with the XB is that wall thicknesses are very low (not enough sealing surface) and not enough clamping force as bolts at the front are far from bolts at the back and there is nothing in between to press the reedplate to the comb where air escapes from one chamber to another. Of course if you could add extra bolts, that would be the best, but you have to drill holes and I am not sure if it is a good idea, so I stayed with the tricky silicone sealing. I am not saying this is the only way, it is just how I did it. 

Zombor






________________________________
From: "burket@xxxxxxx" <burket@xxxxxxx>
To: harp-l@xxxxxxxxxx; robert@xxxxxxxxxxxxxx 
Sent: Saturday, June 16, 2012 6:07 AM
Subject: Re: [Harp-L] XB-40 bending


Hi Robert:

Nice to see folks still in support of the the XB 40.  I picked up a few new keys myself recently.  

I'm not sure if this will help, but:

I recently had a problem with a brand new, out of the box Low D XB40 which had a very weak and unresponsive 1 and 3 hole draw.   Phhhffftttt,   Phhhffftttt.  (sounded like that- right :)  The 2 and 4 draws and all the low blow notes were nice and tight.  Not a good way to start a
 relationship with a new harmonica.  

In taking it apart and checking the reeds, I noticed that the 1 and 3 draw gaps of the primary notes were set pretty high and not profiled all that flat  (   \___    ).   I worked on this a bit, but still did not have much improvement.  I then looked at the sympathetic/ bending reed gaps for those same notes and noticed that they were gapped "way" high. Almost as high as the primary reeds themselves.

All the other bending reed gaps for the other notes (except the 1 and 3 draw), were set very flat, and very tightly gapped.  I re gapped the bending reeds for the 1 and 3 draw almost to where they were closed, made a slight tuning adjustment to the low E, and the harp plays great now.  That fixed the problem for me.  I have to thank Rick Epping for pointing me in the right direction in terms of how the reed chamber, primary, and sympathetic bending
 note reeds interact on this amazing piece of harmonica construction.  

It makes sense that if the bending reed gap is too high, you end up leaking critical air that should be going to the primary reed.  

I'm going to take a look at my other keys and see if there are any similar problems.  If others have any other tips for maintaining and working on the XB I'd be very interested in hearing your experiences.


Good luck
Burke T.



Message: 1
Date: Thu, 14 Jun 2012 16:31:30 -0700
From: Robert Hale <robert@xxxxxxxxxxxxxx>
Subject: [Harp-L] XB-40 bending
To: harp-L list <harp-l@xxxxxxxxxx>
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I have an XB-40 in A.
What reed adjustments can I consider for making Blow 3 and 4 a little more
responsive?
Everything else is sweet.

Thanks.

Robert Hale

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