Dear all,
I just had my antique Wallis refurbished and it came back with the pads replaced by circles of cork. Is this common practice? I thought leather or silicon was more likely.What do I know. Oh, and one of them leaks like crazy so I can’t get bottom D/E. 
May I ask your (collective) advice? Thank you,
Julia C
Circles of perfectly-faced cork may certainly be used as pads. This is not an uncommon practice for both oboe and piccolo, two instruments that have a well-earned reputation for being extremely hard to pad and regulate.
I have seen piccolos padded in this way that played beautifully!
A repairman will usually “float in” the cork pad on melted shellac.
On your key that leaks, I would suspect the cork has broken loose from the shellac behind it and is moving freely in the cup.
Any good repairman ought to be able to melt the shellac and reattach and reseat the cork pad. I wouldn’t recommend trying this yourself, though–there is a very real danger of burning yourself or even catching something on fire.
I would personally prefer good cork pads to silicon–I would think they would be less noisy.
–James
A famous piccolo repairman told me once that cork pads felt like “playing with little poker bettting chips under your fingers.”
Some players prefer cork pads because supposedly they give a brighter sound. They also last for a long time (which may be one of the reasons repairmen don’t like them).