[Harp-L] Introducing the GASKET-VALVE System

[Vern]

> On Jun 12, 2019, at 3:47 AM, <bren at xxxxx> <bren at xxxxx> wrote:
> 
> Hi Vern, David and Harp-L peeps,
> 

> Thanks Vern for your typically sceptical, combative queries!
> 
In the spirit of peer-review, I plead guilty to “sceptical”.  But “combative”……never!
I stand in awe of Brendan’s harmonica playing and would never question a word he utters on that subject.

> Most of your questions relate to chromatics, but for now we're only releasing the diatonic version. Chromatic Gasket-Valves for existing chroms would require all the in-situ valves to be pulled off and their glue patches thoroughly removed. That's a job most chrom players will not wish to do, I think! Tedious and rather pointless. For them it still makes more sense to replace individual valves as necessary. 

I agree.
> 
> However I'm hoping in the future the Gasket-Valve idea will be licensed by one or more manufacturer, to be installed on chromatic harmonicas at the factory. It would save them a lot of time and cost, I believe. A couple of manufacturers are currently assessing it, so let's see what happens.

GVs would be a boon to mfgrs  because one operation replaces 12 or 16.
> 
> But anyway, to answer your chromatic Gasket-Valve questions:
> 
> - The mouthpiece assemblies are made for a given height of the comb+plates.  Would not four GVs increase that height?
> The GV material is about 0.1mm (.004”) thick. Assuming no extra spring material for two-part valves (not decided at this stage), that's only 0.1mm extra height on each reedplate, because the outside valve is a strip attached with double-sided tape behind the coverplates. If you had an extra spring part on the inner Gasket-Valve it would be thinner, maybe 0.05mm. So at the most 0.15mm extra height per side. I think exI attach some pictures for a test Seydel Saxony design to give you the idea.

I understand.  I agree that most chromatics would tolerate that much increase in plate and comb height.
> 
> - If the GV material is stretchy (like Ultrasuede) would not alignment of all 12 or 16 valves be impossible?

> It's not stretchy, it's stable. I don't want to reveal the material at this stage, but it is a food-safe polymer often used for drink bottles etc.

OK it is not stretchy.
> 
> - When one valve fails, does the repairman replace the whole (presumably expensive)  gasket/set?
> Can do, or he/she could simply cut it out and replace with a single valve of a different type. I show how to cut out the valves with scissors in this video (12:41 - 14:03):
> https://www.youtube.com/watch?v=nT7-ZAH0W9Q&t=45s <https://www.youtube.com/watch?v=nT7-ZAH0W9Q&t=45s>

OK, I understand cutting out a failed GV valve.
> 
> - What holds the outside GVs in place against the plate, glue?  Longer screws with washers and nuts?

> Double-sided tape. You can see me applying them in the same video on diatonics (egg at 7:18 - 7:58).

OK, double-sided tape.  This is arguably a form of adhesive or glue.

> - Because they get wet, more than 50% of valve replacements are outside on blow reeds.  Replacing one outside valve seems a lot easier and less costly than replacing the whole gasket set.
> As stated before, there is no incompatibility between using the multiple-valve Gasket-Valve parts and replacing individual valves if you wish to.
> 
> Incidentally, that test Seydel chrom with the single-piece Gasket-Valves (no extra valve spring) plays very well several weeks after I installed them, no valve issues so far. It's still early days with this new approach to valving harmonicas, but all the evidence from my own testing indicates the valves are stable and reliable over the long term. As well as playing extensively with Gasket-Valved harps at home over recent months, I've also done several gigs using them. Believe me, I would certainly not be releasing the Gasket-Valve system if I weren't confident they will work well for other players too - the repercussions in customer service issues would be too much of a disincentive!

I don’t see how this differs much from Mylar of equal thickness which is prone to sticking and popping.  However, the undisclosed material may be different in some important way. It is textured/bumpy and that may help. If it it performs well, then the interesting question will arise as to what properties make it so. 

I make valves as close as I can get to 1/8” or 3.2mm.  Scaling from your picture which shows perfect alignment, it appears that your valves are tapered from about 3.8mm at the base to about 2.7mm at the tip.  Assuming that the slot is 2.1mm, This allows only .3 mm overlap along the sides at the tip.  This alignment accuracy would be much harder to achieve over the length of a chromatic.
l 
> I hope that answers your questions sufficiently.

It does and thank you.

One additional advantage shown in the picture is transparency.  You can easily see (mis)alignment .  Also, you can backlight the plate and see the reed-slot clearances.  Neither is possible with opaque materials such as Ultrasuede.

Wax on the plate helps regardless of reed material.

Vern