Gasket Caulk?

[harryball]

I saw some caulk going into window gaps that when it dried was like a rubbery gasket material. It occurs to me it would make a good gasket on a vac mask.

Anyone know what this magic caulk is and where I can get it?

/RB

[Gary Campbell]

Robert...
Butyl is my exterior window caulk choice. It stays flexible. If you want a real gasket use RTV silicone. If you want it to never come loose, use a urethane caulk like Vulchem or Sika Flex. And lest we forget, there is always 3M 5200.

Butyl is sometimes sold as "gutter caulk" by DAP and others in the big box stores