Primers. What are they used for? Do I need a primer? Do “paint-and-primers- in-one” work? We’ll take a look at all these questions along with more in this blog post. Find out what your project needs and whether or not a primer is necessary.
What Are Primers?
A primer is a paint-like substance that is applied to a substrate in order to protect and prepare it for painting. Everything in or outside your home that has been painted has also been primed (at least, it should have been). Without a primer, you are setting yourself up for paint failure. You can find a number of different primers from different paint brands for different purposes, but in the end, they're all made for the same goal: preparation for painting.
What Do Primers Do?
As mentioned above, primers prepare your surfaces for painting. However, there are three main attributes to primers
o Sealing
o Adhesion
o Stain-Blocking
Sealing. Unpainted, porous surfaces such as wood, drywall and concrete have pores that will absorb a large amount of paint. In order to use less paint (which is typically more expensive than primer) and to create a more even base, primers fill these pores in with their high-resin formulas. This not only saves from the amount of paint you need to buy, but also creates a surface that will have a smoother, more even finish.
Adhesion. This is probably the most important purpose of primer. Paint does a very good job at protecting your home from the harmful ultraviolet rays of the sun along with general weather. However, itself is not a very “sticky” substance when it comes to long term durability. Primer, on the other hand, is perfect. It acts as a glue bond between your paint and substrate, allowing for a longer life for your project.
Stain-Blocking. This property tends to be the most well-known of the three. Whenever we paint a darker-colored room to a more neutral color, people usually ask, “did you use a coat of primer?” (the answer is usually “no”, since we use higher-quality paints with better coverage). However, that’s exactly what primer can do for you. If you have something that might show through your two coats of paint, then you’ll want to use a primer that can block and trap those stains underneath. Those “stains” could be darker colors, water or smoke stains, rust spots, grease stains, pencil marks, wood tannins, and more.
When To Use Primers
Do you need a primer? Primers are not always necessary, and it doesn’t make sense to waste the time and material if not needed. When it is needed, though, you don’t want to bypass it. Here are some common situations where a primer is necessary:
o Changing from a very dark color to a very light/neutral color
o Blocking any water, smoke, rust, grease or graphite stains
o Blocking out odors in walls (cat urine, smoke, etc)
o Sealing unpainted drywall, wood, masonry, tile or concrete that is going to be painted
o When painting bare metal
o When painting a surface that is very glossy (after a scuff-sand)
o When painting over oil-based paint
o When painting areas where paint has flaked or been scraped/sanded off
When Not To Use Primers
If your surface is clean, dull and in overall good condition, skip the priming step. We find that most interior repaints don’t require much priming, and for exteriors we have actually begun using products like Duration Exterior from Sherwin Williams that have a self-priming capability. That being said, we always have multiple primers on site for when the opportunity arises.
Which Primer Do I need?
Always ask your paint store employees what primer is required, as they can listen to your situation and guide you with their specific products. However, here’s a comprehensive list of the right primer for your job:
o PVA/Drywall Primer: great primer for sealing new drywall. It’s low cost and has great coverage so you spend less money on material
o Wood Primer: used for raw wood. Has medium adhesion and high sealing properties
o Bonding Primer: this is a very high-adhesion primer that is great for glossy surfaces (such as painting over a high gloss trim) and for surfaces that need that extra “bite”. We tend to use these primers on tile, high traffic areas such as handrails, metal surfaces, and areas with very flakey paint. If adhesion is ever a concern, lean on this type of primer as your safety net
o Stain-Blocking Primers: normally oil-based, these primers are exceptionally good at blocking those pesky stains such as water, rust, grease, graphite, etc. These are great to use on exteriors for “spot” priming as they’ll guarantee to hide exterior stains. These primers are also great for trapping smoke and urine odors. They also should be used on woods that are high in tannins- naturally occurring tinted oils secreted by the wood. Tannins, commonly found in richer woods such as cedar and redwood, will bleed through a normal water-based primer or paint, so an oil-based stain-blocking primer is vital for this.
o All purpose: a very general category, many of the most well-known primers are one’s that can do a variety of jobs. Those normally include priming wood, drywall, metal, tile, light water stains, and more. Always read the can for instructions and uses.
o Shellac-Based Primers: this primer really belongs under “stain-blocking primers”, however due to its effectiveness and unique properties, we decided to list it separately. This is one of the most flammable and odor-emitting paint/primers out there, but it does an excellent job at blocking persistent stains.
Oil-based vs Water-based
All paints and primers come down to a water-based or solvent-based formula. Water based formulas are going to use terms such as latex, acrylic or waterborne. These will generally have longer dry times, won’t give off too strong of an order, will be low in VOC (Volatile Organic Compounds), and will clean up with soap and water. Solvent-based formulas will normally be oil-based or shellac-based. These will generally have shorter dry times, will give off strong odors, will be higher in VOC’s, and will require a solvent such as mineral spirits or denatured alcohol to clean up.
Besides the faster dry times, why would I ever use solvent-based? Great question.
Certain applications, such as ones listed above, require a stronger adhesion or stain blocking ability. In those circumstances, a solvent-based product is required.
Paint-and-Primer-in-One?
Aw, the paint-and-primer-in-one. One of the more successful marketing campaigns out there. Many, on the surface, claim to cover in one coat. However, upon further reading, they’ll explain that it must be the same color or very close to the color you are covering. They also will point out that certain applications require an additional primer. In the end, paint-and-primer-in-one’s are not bad. We used to use “Superpaint” from Sherwin Williams often, and it’s a great mid to high quality paint. However, we always used two coats and we never skipped priming. In our mind, the only advantage to a paint-and-primer-in-one is that it has better coverage than other paints. So, a third coat will rarely ever be necessary when using these. For us, we’re going to stick to using “Duration” and other high-end products that have very similar coverage.
Favorite Primers
o Zinsser Bullseye 123 Water-Based Pimer (water based, all-purpose primer)
o Zinsser Cover Stain Primer (oil-based, interior/exterior, stain-blocking primer)
o Zinsser Peel Stop Primer (water-based, exterior, bonding primer)
o Insl-X Stix Bonding Primer (water-based, interior/exterior, bonding primer)
o Sherwin Williams Extreme Bond Primer (water-based, interior/exterior, bonding primer)
o Sherwin Williams Premium Wood and Wall Primer (water-based, interior, wood primer)
o Kilz PVA (water-based, interior, drywall primer)
Final Thoughts
Primers are an important part of painting. They provide the foundation for everything that follows. Each application is going to require the appropriate primer, so always make sure to check with the paint store employees to clarify and confirm. When in doubt, you can always call a paint manufacturer or the manufacturer of your substrate to confirm which primer to use. Stay smart, stay safe, and go tackle your next paint project!
Comments