Patched areas should be spot-primed before painting too, so if you've filled in nail holes or patched dents, be sure to prime those spots after sanding. Without primer, the paint absorbs into the surface unevenly, leaving an inconsistent finish with patched areas showing through the final coat of paint.
If these repairs are small, you do not need to purchase a primer but apply a light coat of your regular paint on those areas once the spackle or joint compound is dry. This process is called “spot priming.” If you already have primer, simply use a little primer on those patch areas.
If the wall surface is smooth, you can skip the primer step. However, if there are textured areas or wrinkles on the wall, you'll need to prime it first. If your wall has been previously covered in wallpaper, you should definitely plan on using a primer before painting.
KILZ® Brand offers a family of hardworking primers suitable for all types of painting projects large and small, indoor and outdoor. Trusted by pros for over 40 years, KILZ® Original Interior Primer is available in a convenient aerosol formula, ideal for small painting projects and spot priming interior surfaces.
Oil-based primer
The average time for oil-based primers to cure is about 24 hours. The paint will be dry to the touch in a few hours, but it will take longer than that for the primer to harden completely (cure). That's why not a lot of people prefer this type of primer, as it can take longer to dry.
Before painting, most primers can stay on a surface for anywhere between a few hours and 30 days. The amount of time depends on the kind of paint and primer you're using, how long it takes the primer to dry, the surface you're painting, and external conditions like heat and humidity.
Paint peeling only usually happens when you're trying to paint over an unprimed or poorly primed surface. For those who aren't sure, give yourself a primer drying time of at least 1 hour, or simply leave your model in a dry and clean place overnight.
You will want to use 2-3 coats of primer to ensure there is a good bond between the new paint and the wall, and also to cover up any previous colors, especially if they are red, orange, or a strange outdated color. In short, you will typically need 2 coats of primer for most painting projects.
The primer coat doesn't have to be perfect, but it should cover the surface (no bare spots) and it shouldn't be so blotchy that you get drips or visible unevenness.
Most latex primers dry to the touch in 30 minutes to one hour. But for best results, don't paint until the primer completely dries—which can take up to 3 hours, depending on temperature and humidity. Once the primer is completely dry, it's prime time for painting.
Then, you are free to prime and paint. Many professional painters use a tinted primer before painting. This is an inexpensive way to bring your walls close to their final intended color before adding the more pricey topcoat. Ask about this at your paint store if you are painting a bold or dark color.
With fresh drywall, the substrate actually absorbs a coating really well, like a sponge. However, because it absorbs so well, without a primer coat, you'll experience uneven coverage, especially along drywall seams. This means you'll need to apply more paint to finally get an even coat.
It is not necessary to prime the whole wall if you're using the same or similar color. When the “spot-prime” areas are dry, you can paint the wall normally. Always prime your walls before painting if the surface is porous. The surface is porous when it absorbs water, moisture, oil, odors or stains.
When painting over oil based paint it's very important to sand the surfaces and prime with an oil based or shellac primer. These types of specialty primers are what will assure a good bond. Quality paint primers are designed to stabilize the surface, harden and bond the surface.
In most situations, a good rule of thumb is to use a primer plus two coats of paint. If you use this rule, you may do one more coat than needed but this won't hurt the final product. There are few situations where this rule of thumb will result in doing too few coats though which is why it is prevalent advice.
The more cars you can prime with a roller and the less time you spend cleaning up, the more savings you'll accrue. The rolling of primer is dependent on the shape and contour of the vehicle. It simply won't work in certain areas, like around the fog light. It is generally recommended for smaller areas.
Using too much primer may make your skin slippery and oily, especially if you're using a product containing silicones or hydrating ingredients. Be careful with colour-correcting primers, focusing on areas of discolouration. If you use too much of a green primer, you may look sickly.
After your first coat of paint is dry, it's safe to recoat typically after four to six hours. A good rule of thumb is to wait at least three hours to recoat your paint or primer if it's water-based. Waiting 24 hours is best for oil-based paint and primer.
You're painting unfinished drywall or plaster.
Two primer coats are recommended in this scenario because much of the first primer coat will be soaked up by the wall; the second coat will replenish any primer absorbed by the surface and hide any flaws in the wall.
Applying the second coat too early will result in lost time, money, and effort. Not only that but it'll also create additional stress that's not necessary. Applying the second coat too early will result in streaks, peeling paint, and uneven color.
As Phillips mentioned, you want to wait a full minute or more to allow the primer to dry completely before going in with makeup, as this will help to curb pilling or patchiness. Another mistake people make is choosing a primer that's wrong for their skin type.
For your finish to be vibrant and not dull sanding after primer will ensure that the finish is not excessively dulled when you apply your paint top coat. You will typically use finer grit sandpaper and aim to achieve a smooth wood finish so that you get a fine appearing wood finish when you apply your topcoat.
A VOC is a gas that various products or processes emit into the air. They're both dangerous on their own and when they mix with other pollutants to form new gasses. So, no, you don't want to sleep in a freshly painted room unless you've used low-or-zero-VOC paint products.