Portlights stuck to rubber gasket - how to lubricate?

[Disailor]

I use SuperLube for many problems on board. It prevents plastic threads from becoming difficult (PB jars storing varnish/linseed oil), waterproofs electrical connections, keeps dodger zippers running freely, etc,etc

[GreenWave]

I use silcone grease. Once I started, all my leasks stopped. I also use it to lube the strainer cap o-ring whenver I clean them out.

[rwidman]

Originally Posted by Jammer

Talc. You can get unscented talc for tires from auto parts places, or Grainger, or Aircraft Spruce, or any number of other places. It's used to keep inner tubes from sticking to tires.

Baby powder, athlete's foot powder, many things in a common medicine cabinet are mostly talcum powder.

I put new rubber gaskets on my floor hatches and had the same problem as the OP is having with his portlights. Talcum powder spread on the mating surface fixed the problem.

[Quebramar]

I use Vaseline from a drugstore. Recommended by boat builder to be applied prior to winterising

[Capt.Don]

I've been using fan-belt rejuvenator spray.
Don

[CaptTom]

I ended up buying some Super Lube at Lowe's. Works pretty well. The ones I rarely open do stick a bit, but I can open them by hand now, no prying. It also seems to work well on the hand-operated Jabsco head pump.