(4) Good, both for static and dynamic seals
http://www.efunda.com/designstandards/oring/oring_chemical.cfm?SM=none&SC=Castor%20Oil
Thanks. Useful.
when castor oil drys it becomes hard and acts like glue,. i would not use it anywhere near seals.
when i was a kid i used to build model airplanes, we used castor oil for 2 things, we soaked rubber strings in it so it performs better, in rubber powered planes, but it can’t be exposed to cold, it will harden, and would make rubber hard and brittle.
second use was additive to fuel for compression engines, (ether, castor oil, kerosene) , all of those engines needed to be taken apart and washed in solvent, cuz if you do not, and let it sit with oil inside, in few months it would glue all parts of the engine together, and it would be a lot harder to clean.
i would not use anything but silicone grease on seals