Your ceiling may have been oil based, or really anything other than latex. If you used latex primer over oil then there is really nothing you can do except remove it and get a super low gloss oil base.
Yes, you can if you are sure you need to.
Any oil based chalky surface sealer should lock the calcimine down, providing a stable surface that will accept any latex ceiling paint.
Yes, it is always necessary when carrying out repairs . The area surrounding the repair is sanded , and the primer patch extends outside the repair onto this "feathered" area. Both epoxy and urethane based primers are suitable.
Yes. Oil based primer works over just about any surface.
Epoxy primer has to go over a bare surface otherwise it can act as a stripper, causing the base coat, along with the newly applied epoxy to delaminate or lift from the surface.
Over Your Head - 2006 Ceiling Repair 1-12 was released on: USA: 13 January 2007
Not and have it stay. Start by sanding the ceiling. make all necessary repairs to cracks, water damage etc. Prime the ceiling with a top quality high hiding primer... if you have water damage be sure to use a non-water based primer, I use Kilz (not kilz 2) with great results. Ten use a Kitchen/bathroom specific paint as your top coat.
Depending on what type of spackle you are using and how thick it was applied it may need to dry longer, but you also need to prime the spackled area before painting. My experience has been to use an oil base primer and any type of paint can be used over it, oil primer works well for a bathroom.
Yes, you can if you are sure you need to.
No
you only use primer over bare wood or stains. If you have really tough stains you might need to use shellac based primer, otherwise any stain covering primer.
Any oil based chalky surface sealer should lock the calcimine down, providing a stable surface that will accept any latex ceiling paint.
Either oil or latex primer can be used over interior latex paint.
Latex.
To fix a ceiling that was spackled with drywall mud instead of spackle you can use sand paper to scrub it. I don't understand why you have a problem with it. That's quite common. you normally just paint primer over it. Using sand paper to scrub it is going to be extremely dusty.
Primer is a base coat that can accept all types of paint so no stripping is necessary and you can definitely primer over primer but remember to fill and sand before to eliminate blemishes and maintain a smooth finish.
No, it isn't a primer or any use as one.