Have a mishap...

I have a vintage glass dome lantern that i installed in the toilet. It is the classic type of threaded base into which you can screw a glass dome or a glass jar, with E27 socket inside. The base is made of porcelain

Right now i relamped it, and went to screw the glass dome back in place. I screwed it lightly but a bit askew, and noticed that it stopped after just 1 turn....

Now i CANNOT get it off at all. It did not move when on the ceiling, i pulled the entire thing off (ripped out the screws from the ceiling and cut the wires) so now it is down here. I tried unscrewing the base with 2 hands while holding the dome tight with my legs, NOTHING MOVES it is stuck dead

How i take it apart again ?

Do you have WD40 to lubricate? Always take your time, or you may break the glass.

WD40 on glass or the non glazed side of the porcelain ? i sorta dont like this

Meanwhile i tried to submerge the dome (only the dome but not the base) in cold water to get it to somehow shrink, but no effect

Or soapy water...
But you will have to clean out and maybe replace all the electrical parts after that...

Or gentle tapping (with some small screwqdriver,...) while pulling it to unscrew - the tiny shocks may cause the materials to jump over and finally get loose. But just gently - you do not want to break it...

I thought of wrapping the dome with some sort of rubber (medical tourniqet, ...) to spread the force more evenly and try harder to just turn it. If i just apply force without anything "sharp" or etc, will this let me apply more force while still not breaking it ?

Maybe a tool like this ?

Did you install the lantern in the toilet?

The tool that sol suggested sounds like the best idea to me. I have screwed these covers on the wrong way before, and nothing could remove them other that excessive force.

I will get around to trying that in a while