There is a brand of paint sold in most hardware outlets for painting plastic or vinyl . This paint does not need primer first. It is called Krylon Fusion.
PVA is a better primer for new drywall. Do you need it, not really. Any good latex primer will do the job just as well. I guess it really just depends on what you expect your primer to do. Cheap primers will seal the drywall, but not much more. I find bonding primers and pva primers will provide a much more solid platform for topcoats. They may cost more and be a little overkill, but they will provide you with layer of primer that will allow your topcoat to dry in even. You can also dry a high build primer, which is the product I prefer to use. They give you a great platform to work from, and since they are usually about 3 mils thicker that standard primer, they fill in a lost of voids in your wall. If you go with this kind of primer, it is best to spray it. You really can't achieve the mil build up you need from a brush and roller application. If you use the roller application, and are worried about really sealing the wall and filling voids, I would recommend two coats of primer.
Yes, you can.
Primer is needed when there is no existing paint is present. If new drywall is present then a drywall primer is applied, a paint primer then paint. Read the instructions on what ever paint you buy. Most new paints say that you don't need to prime over the old paint and they cover better then they use to. So you follow the instructions on the new paint, it will either recommend priming the walls or it won't. But if you don't use a primer over old paint, you should buy a paint cleaner that preps the wall for the new paint. This will give the old paint a good surface so the new paint adheres well to it and down the road you don't get bubbling or peeling.
I wouldn't use old paint that may have separated. Buy a primer.
The fairly new adhesive, PL Premium, will glue vinyl and leather.
New galvanized what ? -Are you talking about galv steel framing ? If so it need no priming. Steel studs are within the wall and do not need any kind of primer or paint.
Yes it can. (but it's kind of expensive to use as primer ! )
Regular drywall primer.
Normally, installing new vinyl directly over old vinyl is not recommended because most manufacturers will not honor the warranty. Any bumps or dips in the surface can translate through your new vinyl. Dye or stains from the old vinyl can also seep into the new vinyl. But you can remedy this by applying an embossing leveler over the old vinyl, and then sealing it with an acrylic sealer. Then trowel your glue onto the sealed surface, and install your new vinyl. Most recommended practice, however, is to remove the old vinyl OR install new wood underlayment on top of the old vinyl. Then spread your glue and install new vinyl. As always, check the installation instructions for your new vinyl.
Vinyl siding looks good and is easy to install. You shouldn't have any problems using vinyl siding on any house, old or new. Its lightweight and just nails right on.
The New England Primer was removed from public schools in the middle of the 20th century.
About 3-4 gallons of primer. Don't be stingy with it. Better primer coat improves your finish coat and primer is cheap.
vinyl is impervious to liquid and does not need any sealing.
"Drywall primer" -Yes, -it's called exactly that -right on the can !