Stevelegh
194 posts
Apr 19, 2011
4:32 AM
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Hi everyone,
This might be a rubbish idea, but I'm sitting at work and I read Boris' post about Sjoberg combs.
I sell radiators for a living and something just came to me. In order to join cast iron radiators section by section, you use fibre or rubber rings in order to achieve water tightness.
Wouldn't the same principle work with harp combs. If you took a comb and put a thin layer of rubber / silicone / polypropelene on the flat surfaces then fitted the reedplates, you'd get a airtight seal.
I don't know if this would affect the mechanics of the harp, or make a huge variation in tone, but providing the 'rubber' was thin enough, surely this would be a big help.
Another step would be to create a 'rubber' comb. Providing you used a material hard enough not to distort, but soft enough for the reedplate to 'bite down' into the material slightly, you would achieve a totally airtight harp.
Any thoughts? Has it been tried? What were the results?
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chromaticblues
782 posts
Apr 19, 2011
6:16 AM
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Yes! Thats why I put a layer Bert's bees chapstick on each side of the comb. The chapstick works like silicon form-a-gasket. It dries up after awhile and looks like wax. Works great for wooden combed harps.
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Stevelegh
196 posts
Apr 19, 2011
7:02 AM
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Todd!
You've just used a word I haven't heard in a while and brings me back to a previous career of selling skateboards. Durometer.
A hard polyurethane would be an interesting material. I wonder if it would deaden the tone beyond use? I'd assume it would need moulding as opposed to CNC cutting.
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toddlgreene
2907 posts
Apr 19, 2011
7:18 AM
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I don't see why cnc wouldn't work, or possibly die-cutting(cheaper), but regardless-bonding to the comb would be crucial. Seems to me that keeping excess material from inside the comb would be ideal, i.e., only having the gasket attached to the comb in way of the cover plates for a good seal, and less sound-deadening.
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Todd
Eudora and Deep Soul
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Stevelegh
197 posts
Apr 19, 2011
10:09 AM
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Hey Todd,
I had a little look into this and you can get Polyurethane sheet for food uses (conveyor belts etc).
I might see if I can get some samples
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isaacullah
1466 posts
Apr 19, 2011
11:05 AM
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I think this has been done already. The "Turboliner" from turbo harps:
This is not to discourage you, but just to show you that it's out there...
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Stevelegh
199 posts
Apr 19, 2011
11:18 AM
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Isaac,
Interesting that it's using the reedplate template rather than the comb template. Makes some sense, although I'd imagine some alignment issues.
I did think about another possible material. My dad used to steal it from work. He used to call it 'Heatshrink' It was a tube of rubber that you placed on the think you wanted it to 'shrink' onto and put it over a flame.
Quite how it would work with comb tines, I don't know, but I may find some and have a play around.
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toddlgreene
2908 posts
Apr 19, 2011
11:39 AM
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Damn, Isaac bursts my bubble. Now, if you'll excuse me, I need to go buy some Powerball tickets.
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Todd
Eudora and Deep Soul
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MrVerylongusername
1676 posts
Apr 19, 2011
4:33 PM
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@Isaac
Look again closely - the Turboliner is not acting as a gasket, especially not in relation to the draw plate. The turbo liner appears to add ridges along side the reed to alter airflow around the lateral edges of the reed.
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Jehosaphat
48 posts
Apr 19, 2011
5:44 PM
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First Off: there have been extensive tests done on the ability of players to identify comb material.In all cases no one could on blind testing.Combs were made from polythene to concrete.(search Harp-L)
Back when i used wooden combs the best material i found for sealing was a paint on liquid rubber that is used to seal ornamental ponds and potable water tanks..Completely non toxic(fish swim in it) and when it cures you have a thin pliable membrane for the plates to clamp onto.
I used to dip the combs into the tin of it and leave to dry.That way the inside of the comb teeth got a thin coating too and would effectively make slots more airtight,easier than embossing.
In fact those harps were almost too airtight in some ways.I had to play a lot softer than i normally would,sorta like you do with a good embossed custom.
Worth trying for you guys who like to experiment.
If the membrane is dry when you assemble the harp you can dissasemble it later as the plates don't stick to it
Last Edited by on Apr 19, 2011 5:47 PM
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nacoran
4026 posts
Apr 19, 2011
6:18 PM
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Hey Todd, if you ever need a crazy harmonic invention idea I've got about twenty swirling around in my head and no way make 'em real! :p
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toddlgreene
2912 posts
Apr 20, 2011
5:21 AM
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Email me nac-I'm a 3d amigo, and I've done a few patent drawings over the years as well, and thousands of fabrication drawings.
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Todd
Eudora and Deep Soul
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HarveyHarp
230 posts
Apr 20, 2011
8:11 AM
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About 12 years ago, or so, I decided to try to spray a Lee Oskar comb with rubber. I used the kind that you spray on tool handles, to insulate them, and it worked great, so I sprayed my whole set of Lee Oskars. Well, they started flaking off a little, and getting stuck in my reeds. It was a bad and sort of costly experiment. Any one have a spare set of Lee Oskar Combs? Anyone want to buy a set of Lee Oskar Harps with flakey combs. LOL
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Last Edited by on Apr 20, 2011 8:11 AM
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isaacullah
1469 posts
Apr 20, 2011
8:50 AM
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@ MrVLUN: Well I'll be! You are right. I just always supposed that they were being used as a gasket, but looking at the detailed explanation below the main picture, they are instead being used to change the airflow into the reed... Hmmm. I wonder if that actually does anything?
Actually, talking about gaskets and airtightness. I think it would be pretty cool if someone could mill a brass comb that is also the reed plates. That is, an entirely one-piece sort of deal where the reeds are screw directly to it. It'd be a little tricky to drill out the screw holes for attaching the blow reeds, but I think it could be done. You'd need some serious CNC action, or maybe even a laser cutter, but I think it could be done. That'd be on airtight SOB, though!
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MrVerylongusername
1678 posts
Apr 20, 2011
10:29 AM
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The turboliner also goes under the draw plate, i.e. not between the plate and the comb (presumably it is self adhesive).
Is this just one of Turbodog's ideas or are these actually in production?
Great idea BTW!
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nacoran
4032 posts
Apr 20, 2011
6:35 PM
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Isaac, that's one of my crazy ideas! Another possibility would be two thick reed plates that came together without a comb in between. It would basically accomplish the same thing but still let you work on the reeds from either side.
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Nate
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