I've always read with interest the lengthy discussions about proper
ways to seal leather.  I'm going to stick my head in the noose here,
but has anyone ever used Organ Supply Industries' Silicone Leather
Conditioner, a silicone solution that comes already diluted?

It's to be applied after the leather is glued in place.  I've used
it many times to seal bellows and organ pneumatics.  You can see a
significant decrease in porosity after one or two applications.

I read discussions about diluting bathroom RTV, which is silicone.
It seems like purchasing the product already suspended in a solvent,
most likely naphtha or heptane, would be the way to go.  This product
has been on the market for years.  I'm just surprised that no one has
ever mentioned it, either pro or con.

I know that pipe organs operate at much lower pressure differentials
than those seen in a vacuum system, and may not provide as much
sealant as other methods.

Jim Quashnock