You don't have to , buti f it makes you feel more secure go ahead, it won't hurt.
Yes, it is absolutely necessary, as it covers the seams smoothly. If you don't prime it you WILL see seams.
yes If you dont prime new drywall, then there is a chance that the orange peel texture maynot cover all unpainted surfaces and you may have to repaint due to the obsorbtion of the paint in the drywall. It also helps seal the surface of the new drywall and makes for a better and more uniform finish.
You prime it with drywall primer.
No, the prime coat can go on anytime.
No, it isn't . The wood and drywall are NOT contaminated.
Hello! Just a couple of guesses as to why the drywall compound is coming off the drywall while you are attempting to prime: First, is the compound totally cured; that is, is it hard and dry? Second, are you using a primer that is specifically designed for new drywall? Lastly, maybe too much paint, or even overworking the paint could saturate the compound, turning it back into a wet goop.
Yes, you can use it....but what are you trying to do? The drywall primer is specifically designed to seal the drywall and make the surface uniform. You will not get any benefit from using it on top of a finish coat except for using it as a base coat for changing colors.
In the best of all possible worlds, YES. If you are doing new construction yourself, then a primer coat before installation of trim & cabinetry is fantastic. Wish more of the "pros" where that conscientious.
Regular drywall primer.
You can't. Prime over it with a good primer.
Depending on how bad the cracks are just filling them may or may not last very long. Sanding it all the way down to the drywall will make blending the new compound to hide the seems in easier but not completely necessary.
tape, float, sand, re-float, re-sand. . .then prime
"Drywall primer" -Yes, -it's called exactly that -right on the can !