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Re: A clarinet plays better than Bb. Why?

Author: Chris P
Date: 2022-08-03 01:43

You don't get (create) a seat (impression) in a cork pad - well prepared cork pads seat against the equally well prepared toneholes. They will of course develop impressions over time depending on spring tension of closed keys and from the finger pressure of the player, but cork pads don't need excessively strong spring tension nor gorilla-like grip to close them against their toneholes when they're installed.

There's two ways you can seat cork pads.

One way is to glue (with shellac) the cork pad directly and solidly into the pad cup and then grind the face down with several grades of pumice block (from coarse to smooth) and check how the pad is seating against its tonehole. This method is time consuming as you need to take the key off each time you grind it and check your progress with a feeler gauge and grind down the area that's seating heaviest to even out the pressure between the face of the pad all the way around the tonehole crown and also ensuring the pad side wall is even all the way around the pad cup wherever possible.

The benefit of this method is the pad is very solid and stable as it can't move in the pad cup. The downside being the pad can't be shifted in the pad cup should it need to be (eg. if a key gets bent) and can only be adjusted by further grinding on pumice until it seats.

Another way which is much easier is to grind the face of the cork pad on several grades of pumice block and dome the back of the pad so it can shift around in the pad cup fairly easily, as well as making the pad the correct thickness so the pad sits evenly in the pad cup (which isn't always possible on the side keys of many clarinets). Then install the pad in the pad cup with shellac as that provides a solid foundation as opposed to hot glue as Buffet and others do which is much softer. You may have to check and regrind the pad as the heat of molten shellac can warp the cork pad if the grain pattern in the cork isn't lying parallel to the surface (and cork DOES have a grain pattern like wood).

Whilst the shellac is molten, the pad can be shifted around in the pad cup until it seats against the tonehole and will then remain seated once the shellac cools and hardens. The benefit of this method is the pad can be adjusted at will and at any point in time. The downside is if not enough shellac is used it can lead to noisy action when the pad closes if there's a void (an air space) left between the pad and the pad cup or the pad can eb unstable if it's not fully supported with enough shellac.

In any case, cork pads should seat perfectly by using light finger pressure or spring tension to simply close them against their toneholes as opposed to being forced to close onto them. Excessive spring tension or finger pressure will cause cork pads to stick to their toneholes (especially if they're in a location prone to getting wet and not blotted dry after playing) or cause them to crack.

Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.

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