Kilz vs Zinsser- Making the Best DIY Primer Choice

Paint primers are the foundation of every great paint job. Whether you’re painting furniture or a driveway or leather, you need to apply a good-quality primer first to ensure the best outcome for your project.

When choosing paint primers, the decision always comes down to two major product brands – Kilz Vs Zinsser.

These two are the most popular choices in the painting community, and every painter likes them for different reasons.

The different opinions about them cause so much confusion, especially for newbie painters. Therefore, in this article, I compare Kilz Vs Zinsser to help you select the best one for your project.

Zinsser is a thick and strong product; therefore, it offers adequate surface coverage and bleed-through protection. These features also make it durable, making the paint job hold for longer.

However, Zinsser’s thickness is also its downside. The heaviness of the product makes it hard to stir and apply, which can be a problem, especially for beginners.

On the Other hand, Kilz is lighter than Zinsser; therefore, it’s easier to stir and apply – that’s why many beginner painters love it. It also has a more intense white color; thus, it provides ample surface coverage.

On the downside, Kilz’s thinner consistency means that you’ll need to apply more coats than Zinsser to achieve the perfect coverage. It also doesn’t provide great bleed-through protection.

This is just a summary of the key things you need to know about Kilz Vs. Zinsser, but let’s dive deeper into the properties of each to help you understand them better. I’ll compare all their physical and functional properties to help you make a more informed choice.

What Is Kilz?

Kilz is a primer brand made by Masterchem industries – a well-established company that makes surface coating products. Most of their products are water-based except their Kilz-original interior primer, which is oil-based.

Because their base/solvent is water, Kilz products have a thin consistency; therefore, they are easy to apply.

They also produce low fumes as you use them; hence, they’re gentle on the respiratory system. Besides, they are perfect for both indoor and outdoor projects.

Even though Kilz is non-toxic, it produces a powerful odor as you apply it. Therefore, you must always wear protective gear to prevent the smell from affecting your work.

You must also ensure that your workspace is well ventilated and far from other people to keep the smell from irritating them.

You can apply Kilz primers with either a sprayer or a paintbrush. Both methods are ideal because the product is already thin, so there’s no need to dilute it further.

Sprayers are perfect for professionals who know the proper spraying techniques, while paintbrushes work well for both professionals and newbies.

Actually, newbie painters get the most advantage with paintbrushes because it is hard to leave brush marks when working with thin products. Thus, they do not have to fret about making such mistakes.

Even though their products are water-based, Kilz manufacturers have created several versions of their product, each with a unique function.

They have adhesion primers for sleek surfaces, primers made for drywall, and even all-purpose primers that suit different applications.

For this reason, you can use these products on materials like wood, concrete, galvanized metals, etc.

Pros of Kilz

  • Kilz products dry fast; therefore, you won’t have to wait long for them to dry between coats before proceeding with painting.
  • They are water-based; therefore, they don’t emit toxic fumes, making them safe for you and the environment.
  • You can apply Kilz primers using either a paintbrush or a sprayer, allowing you to work with whichever one you prefer best.
  • Their thin consistency makes them easy to use, and you won’t leave brush marks on the coat.
  • They are versatile, so you can use them to prepare many kinds of surfaces for painting.

Cons of Kilz

  • They produce a pungent odor as you apply. The smell is not toxic to your health, but it may prevent you from doing your work effectively.
  • They are thin; hence you’ll need more coats to guarantee proper coverage.

What Is Zinsser?

Image of primed concrete so, How Long Does Paint Primer Take to Dry?Zinsser is a primer brand marketed by Rust-oleum, a well-known surface coating manufacturer in the world.

When the manufacturers made it, they used different solvents to create different types of primers.

This move gave consumers more product options to suit their specific needs.

The different types of Zinsser primers are oil-based, shellac-based, and water-based.

They are all versatile and work well on various surfaces, but each has a specific trait that makes it more suitable for some projects than others.

For instance, shellac-based products are best when your surface is severely stained or has a foul odor, but they release a lot of fumes as you use them.

The water-based versions will not block stains and odors very well, but they are flexible; hence better for materials that expand and contract – materials such as wood and concrete.

On the other hand, the oil-based versions are versatile and durable; thus, you can use them on many surfaces. However, they dry slowly; therefore, they are not suitable for projects that need quick finishing.

Zinsser primers have a thick consistency, giving them better coating abilities than most primers. You can enjoy full coverage with a single coat, and as a plus, their thickness allows you to apply them without sanding.

The reason is that the liquid attaches itself properly to the material, and it will flow out and fill any tiny crevices, thus leveling the surface.

However, you must always sand and repair your substrate if it has more severe damage, even if you’re using Zinsser products. 

Depending on your skill, you can apply these primers with a paintbrush or a sprayer. However, if you choose to use a paintbrush, I urge you to be careful not to slather on too much product because it will take too long to dry or dry poorly.

You may also leave brush marks on the primer coat, which will show through the paint and ruin the whole finish.

Pros of Zinsser

  • Zinsser products have different primer bases to suit various projects and surfaces.
  • They are the best at blocking severe blemishes like water stains and unpleasant odors – especially their shellac primers.
  • They have a thick consistency; therefore, you need very few coats for full coverage.
  • Their thickness allows you to apply them without sanding and not experience paint peels and lifts.

Cons of Zinsser

  • The heavy texture of these products makes them difficult to spread smoothly – you’re more likely to leave brush marks in the finish.
  • Most of their products dry slowly.
  • They produce a pungent odor as you apply.
  • Their products, except the water-based ones – emit VOC fumes.

Kilz vs Zinsser

We often consider several factors when scouting for paint primers. We choose primers with excellent stain-blocking properties if we have a large patch that needs covering before painting.

On the other hand, we will need a proper adhesive primer when we want the paint to stick to a sleek surface like glass or vinyl. 

Kilz and Zinsser’s primers are excellent products ideal for different projects, both indoors and outdoors.

Manufacturers formulate them with almost similar ingredients, but the final products have particular properties that make them fit for some tasks more than others.

So in this section, we’ll discuss the similarities and differences of the different properties of Kilz Vs. Zinsser. We’ll look at essential features such as odor, cost, adhesion, dry time, etc., to see which is the best fit for you.


Consistency refers to how thick or heavy a primer is, and it is one of the most important things to consider during the purchase.

The thickness of a product affects how easy or hard it will be to manipulate and apply the coating.

Kilz primers are thinner than Zinsser’s; hence they are easy to stir and apply. Accordingly, many beginners prefer it to Zinsser, especially when working on their very first project. However, the thinness of Kilz comes with a few drawbacks.

First, there may be a few lapses in coverage which will cause some bleedthrough. You may apply several coats to compensate for this, but it won’t hold up for a long time.

On the other hand, Zinsser primers are thicker; hence they are more durable than Kilz. They offer better converge in as little as one coat, and they prevent stain bleed throughs much better.

On the downside, the thick consistency of these primers makes them more susceptible to brush marks. Therefore you must always be careful during the application or allow a professional to do the work for you.


All coating products have an odor; however, the strength of the smell is what determines how comfortable you’ll be during the application process.

Kilz has a very distinctive foul odor compared to Zinsser, so have a gas mask at the ready if you choose it. The fumes aren’t toxic, but they are irritating all the same.

Zinsser products have an odor too, but it’s not as strong as Kilz’s; therefore, it is more comfortable to use during application.

However, remember that this primer brand formulates their products using different bases, so their smell levels differ slightly.

Their shellac and oil products have the most potent smell, so it is better to use their water-based products if you want something mild.


A primer’s adhesion capability is one of its most crucial aspects. If the primer doesn’t stick to the surface, it lowers the chances of your paint job lasting a long time.

Both Kilz and Zinsser have excellent adhesion properties, but the latter is more powerful. It can adhere to surfaces perfectly, and you can get away with applying it without sanding. You may only need to sand if your project requires the strongest bond for success.

Kilz primers’ adhesion isn’t that strong; hence they require you to prepare the surface by sanding before applying them.

On the bright side, the manufacturers created a specialized adhesion primer,  which you can purchase whenever your project calls for something stronger.

Coverage and Bleed Through

Image showing wood Knots. Know How to Stop Knots Bleeding Through PaintOne of the primary purposes of a primer is to cover the stains that you cannot wash off and prevent other stuff from coming up the surface and through the paint.

Both Zinsser and Kilz offer fantastic coverage; therefore, if you want to know which one’s better, you have to consider the bleed-through protection.

Zinsser products are thicker; hence offer the best bleed-through protection.

They even have a shellac-based product, and we know shellac primers have the best stain-blocking ability.

So if you have a surface like cedar or redwood, Zinsser products are your best bet to keep their tannins from seeping through your paint.

On the other hand, the thinness of Kilz primers sets them back when it comes to bleed-through. Therefore I recommend only using them on surfaces that only require stain coverage.

Rust Inhibition

When painting a metal surface or any surface with metallic components, you must apply a rust inhibitive primer to prevent the metal from corroding after painting.

Both Kilz and Zinsser offer primer options with rust inhibitive additives, but I recommend Zinsser.

I recommend Zinsser because they’re marketed by Rustoleum, a brand known for producing rust prevention coatings and even products that you can apply directly over rust.

Mold Resistance

Both Kilz and Zinsser offer products infused with mold-resisting fungicides. After painting, they help keep your walls, furniture, and kitchen cabinets from irreparable mold damage. However, the difference comes in the way you use the two products.

The Zinsser products do a better job of killing mold and preventing them from growing in the future. However, the Kilz products cannot prevent mold from growing back.

For this reason, you must always remove any mold present, then wash your surface with a  mild acid like regular white vinegar.

The acid will kill any mold spores that remain after washing, thus preventing them from regrowing after applying the paint.

Remember, not all Kilz and Zinsser primers kill mold, so as you shop, look for products that indicate they’re equipped for mold resistance.


When working with a primer, it is customary to sand the surface to give it a little tooth to grip the product correctly. The case is the same with Kilz and Zinsser, but Zinsser has more leeway.

Zinsser products are a thick, powerful blend that will stick to most surfaces without sanding, except sleek surfaces. On the other hand, you must always scuff your surface before applying Kilz primers to make your paint job last longer.

On application methods, you can either use a sprayer or a paintbrush to apply these products.

However, since Zinsser is thicker, paintbrushes will leave marks on the coat if you do not follow proper application techniques.

You can remedy this by thinning the primer a little and using it in a sprayer. You can also still apply the thinned coating with a brush.

Either way, do not use more than 10% of the thinning agent to avoid diluting it. On the other hand, the Kilz primers work well with paintbrushes and sprayers because they are already thin.

Dry Time

Dry time refers to the duration it takes the primer’s solvent to evaporate after applying it. Kilz primes dry faster because they are water-based, and water doesn’t take long to evaporate.

On the other hand, Zinsser products have varying drying times because of their different solvents. The shellac and water-based Zinsser products dry quicker than the oil-based ones, but they all dry slower than Kilz because they are thicker.


Generally, in terms of pricing, Zinsser products cost more than Kilz, so if you’re on a budget, go for the latter. However, since both brands offer different primer varieties, it is common to find a specific Kilz primer that costs the same as a Zinsser product.

Therefore, check all prices extensively to get what works for your pocket.

When Do You Need a Primer?

You need a primer for all your painting projects if you want your work to be smooth and long-lasting. No matter the surface you’re painting, primer is your best bet at achieving a professional finish, even if you’re a beginner. 

Primers are meant to prepare surfaces for painting by solving any problems that may ruin the paint.

There are different types of surfaces, each with unique physical properties; therefore, they all don’t accept paint in the same way.

They need particular kinds of treatment to allow the surface to hold the color so that it can serve the purpose you intended.

Below is a breakdown of each surface and why you need to use a primer before painting it.

Porous surfaces

Porous surfaces have spaces that allow external matter – especially liquids – to pass through them. The most common ones that we paint include bare wood, newly installed drywall, and masonries like brick and concrete.

When you paint over these materials without priming first, they will absorb the paint, which will ruin the surface and the paint job.

You see, paint is a coating. It is supposed to sit on top of the surface to protect it and beautify it. So when it gets absorbed instead, a few things happen.

First, the paint loses its authentic color because most of its pigment is absorbed. Second, the paint job won’t be smooth – it will have an orange peel effect which isn’t beautiful.

Some painters try to compensate by applying several paint coats to counter the wrinkles, but they just use more paint, and it never works.

Therefore, it is always best to prime such surfaces before painting. The primer will seal the pores allowing the paint to sit on top of the surface as intended.

Sleek Surfaces

Sleek surfaces have a smooth and shiny appearance, and the most common ones we paint are glass, tile, plastic, vinyl, etc.

The smoothness of these surfaces becomes a problem when you want to paint them because they don’t have enough teeth to hold paint.

When you paint directly onto a sleek surface, the paint will have nothing to grip. As a result, it will lift and peel off the surface after a short period.

Therefore you have to apply a special kind of primer to act as a magnet between the surface and the paint, holding it fast for a long time.

The best primers for these surfaces are adhesion/bonding primers because they are the only ones that can stick to sleek surfaces.

Stained surfaces

The other purpose of paint primers is to hide any stain that you cannot wash off to prevent it from showing through the paint. Even if you can remove the stains, sometimes they are too many or too embedded into the surface that getting rid of them is just hard work.

In such cases, you need a good-quality primer with good coverage and stain-blocking capabilities. The primer will seal off the crayon marks, water stains, grease stains, and any other stains to give you a blank surface to color.

Painted surfaces

Sometimes after painting a surface, you may feel like you chose the wrong color, or the color you chose may go out of style. In such cases, you have two options – remove the paint and start over or paint over the old paint.

Painting over the old paint is always the easy choice. However, you must always take measures to ensure that the old color doesn’t affect the new one.

There are two main instances when you must always use a primer when painting over a previously painted surface:

When you want to paint a light color over a dark one.

Painting over glossy paint

Darker colors will always show through light colors, which is terrible for painting because it will ruin the finish. Therefore, you must apply a stain-blocking primer to seal the old color before applying the new one.

On the other hand, glossy paint behaves like sleek surfaces – it doesn’t grip paint easily. For this reason, you must always apply a good adhesion primer to help the paint stick.

What Is Kilz Primer Used For?

Here are some of the uses of Kilz primer.

  • Changing Paint Colors

Kilz primers have a deep color that is enough to cover both dark and light colors. They give the surface a neutral color like a blank slate when you paint on it.

For this reason, it is ideal for projects that require you to apply paint over a previously painted surface.

  • Blocking Interior Stains

Kilz’s ability to hide colors also makes it perfect for blocking stains. However, it only works on mild interior household stains. It won’t work well on exterior surfaces with harsh stains like oil grease.

Its thinness won’t hold back the stains for too long, and they will end up seeping through them and show on the paint.

  • Seal Porous Surface

Since Kilz is water-based, it is perfect for sealing porous surfaces, and it works exceptionally well on wood and drywall.

  • Provide Mildew Resistance

Some Kilz products have additives that make the paint strong enough to resist mildew and other fungi. The only catch is that you remove any fungi present on the surface before priming it for the product to work efficiently.

  • Promote Paint Adhesion

The Kilz line has products whose sole purpose is to promote paint adhesion on har to paint surfaces. The other primers also help paint adhere to surfaces, but these get the job done more efficiently.

What Is Zinsser Used For?

Uses of zinsser primer include:

  • Covering and Controlling Mold

Some of the Zinsser primers have powerful fungicides in their formula to help control mold growth. The best thing about Zinsser is that you don’t have to remove the mold with a mild acid first.

You can apply it directly, and it will get rid of the mold and prevent it from growing back. However, not all Zinsser primers can control mold, so when shopping, look for products indicated as mold resistant.

  • Sealing Pores and Hairline Cracks

The thick consistency of this product allows it to seal tiny pores and cracks in the wood. This feature makes it perfect for reclaimed wood or wooden structures that have been standing for a long time.

It is also ideal for the times you want to skip sanding, provided your surface is in good condition.

  • Bleed-through Protection

The one thing that ruins paint jobs is bleed through. Whether from wood tannins or liquid stains seeping up through a surface.

Zinsser is the perfect product to use against these problems because of its consistency. It is thick enough to keep the damaging elements from destroying your work.

  • Priming New Wood Furniture

If you’ve seen new wood furniture before it’s painted, you may have noticed that it is full of tiny nail holes, pencil marks, stains, and sometimes even glue.

These stains are a nuisance to remove, so you need a powerful stain-blocking primer to hide them before painting. Zinsser primers, especially the shellac-based variety, are the best products for this task.

  • Waterproofing

Zinsser created one of the very few waterproof paint primers. This feature makes it ideal for preparing surfaces in moisture-prone areas for painting. Surfaces in bathrooms, kitchens, or even outdoors get the most benefit from this product.

Does Zinsser Primer Kill Mold?

Yes, it does. It is a fungicidal protective coating designed to paint over and kill any existing mold, moss, mildew, and bacteria that cause foul odors.

After application, it keeps the mold and other fungal organisms from regrowing, thus keeping your paint in good shape.

The good thing about Zinsser mold-killing primer is that you do not have to do extensive precleaning. However, if you are a stickler for surety, I recommend killing the fungi with a mild acid before applying the primer.

And when you topcoat the primer, use paint with mold resisting properties just to be safe.

Does Kilz Primer Kill Mold?

Kilz primers do not kill mold, but the manufacturers designed them to prevent the fungi from growing back. Therefore, you must destroy the mold before applying Kilz mold primer to your surface. This way, the primer will do its job as the manufacturer intended.

Before you kill the mold, you must first determine the root cause of the fungi and remedy it before proceeding. It could be a dripping pipe near the wall, high humidity, or even a leaky roof.

Whatever the cause, you must fix it to make the problem go away permanently. Failure to do that can cause the mold to regrow right through your paint and primer, becoming a recurring problem.

Best Paint Primers 

Some of the top-rated primers in the market based on my experience are:


The KILZ 3® PREMIUM primer is a high-quality water-based product that performs three functions – stain blocking, priming, and sealing.

It has a thick creamy consistency with high hiding capabilities – the feature that supports its three main functions. It also has a mildewcide in its formula to help prevent mildew growth after painting.

Since it is water-based, this product dries very fast and is often ready for coating in as little as one hour.

It produces a low odor which is perfect for when you’re working inside, but it also comes in handy when working outside where there are other people and animals.

Furthermore, the Kilz 3 premium primer produces very low VOCs; thus, it is safe for you and the environment.

This product is an excellent stain blocker, hiding heavy or light stains caused by tannins, water, grease, felt markers, etc. Its heavy formula also allows it to hide the color on previously stained or painted surfaces when they need a retouch.

The Kilz 3 Premium primer is a versatile product; hence, you can use it on all surfaces, interior, and exterior. You can use it on wood, stucco, masonry, plaster, painted metal, and properly prepared sleek surfaces.

Furthermore, you can coat it with oil-based or water-based paint; therefore, your options aren’t limited.

On the downside, you need to apply 2-3 coats of this product for it to cover the stains adequately. Furthermore, you cannot use it on floors because it cannot withstand the constant traffic.

Image of Kilz PrimerPros

  • It has extremely low VOC levels at just 5 grams per liter.
  • It performs three functions in one – priming, sealing the surface, and blocking stains.
  • It dries fast because it is water-based and is usually ready for a recoat in 1 hour.
  • It has a fungicide in its formula to kill mold.
  • You can use it on all surfaces, including wood, masonry, and painted metal.


  • You need to apply several coats to cover the stains and colors effectively.
  • You cannot use it on floors.
  • Sometimes it doesn’t hold up well, and tannins bleed through after a while
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ZINSSER® Bulls Eye 1-2-3 PLUS Primer

ZINSSER® Bulls Eye 1-2-3 PLUS Primer is one of the most advanced water-based paint primers by Rustoleum. It is a fantastic sealer and stain blocker ideal for various projects both indoors and outdoors.

The stain-blocking capabilities of this product surpass what we usually experience with regular water-based prime

rs. It delivers benefits like blocking water and smoke stains, functions traditionally associated with solvent-based primers.

The manufacturers of the Zinsser Bulls Eye 1-2-3 designed it especially to resist re-wetting. This means it can se

al in both water-soluble and oil-soluble stains allowing you to complete all kinds of projects with just one primer.

The Bulls Eye® 1-2-3 Plus also delivers excellent adhesion functions that make it easy to paint sleek and porous surfaces such as ceramic tiles, melamine, plastic, masonry, and wood.

It also dries quickly; therefore, your project turnaround time will be fast.

This product also contains a potent biocide that will protect both your surface and your dried paint from degradation caused by fungi.

For this reason, it is perfect for use in high humidity areas such as bathrooms and laundry areas because they are more prone to mildew attacks.

Image of Primer On Kilz Vs ZinsserPros

  • Water-based, therefore it dries fast – 30 minutes-1 hour
  • Blocks even the tough stains caused by water and smoke
  • It produces a very low odor
  • It has low VOC emissions
  • You can use it on indoor and outdoor surfaces
  • It kills and prevents mildew from regrowing


  • It is a little thick; therefore, it is easy to leave brush marks.
  • Not ideal for use around food
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ZINSSER® B-I-N Advanced Synthetic Shellac Primer

As the name suggests, the ZINSSER® B-I-N Advanced Synthetic Shellac Primer is shellac-based. It is one of the best stain-blocking primers that hides the stubborn stains that won’t wash away.

It is also thick enough to seal wood knots and prevent tannins from bleeding through the topcoat.

This product has an odor, but it is not as harsh as standard shellac primers. It dries fast like most shellacs and delivers excellent adhesion to help paint hold out for a long time.

Even though this primer dries quickly, it doesn’t dry all the way through; therefore, you should not touch or handle the surface aggressively until after 24 hours.

You can apply this primer using a paintbrush or a sprayer, but I recommend sticking with the paintbrush for best results.

From tests we carried out, you must thin this product before using it in a sprayer, or use it unthinned but use a sprayer with a 310FF tip to get a uniform spray.

When it comes to sanding, you must wait for the primer to dry for at least 24 hours before you do it. When you sand it before the entire day lapses, it will roll up and clog your sandpaper.

Note: Even though you can use this primer on both interior and exterior surfaces, you cannot use it in the same way for both of them.

You can use it as a whole-surface primer or for spot-priming interior surfaces. However, it is best only to spot prime when using it on outdoor surfaces.

The reason is that shellac primers do not do so well outside; therefore, if you use them on the whole surface, your paint won’t hold properly.

Image of Wood PrimerPros

  • It is Shellac-based; hence it has excellent stain blocking properties.
  • It dries fast
  • It delivers excellent adhesion
  • You can apply it by brushing or spraying


  • You can only use it for spot priming on outdoor surfaces.
  • It is sticky and hard to clean up
  • It gums up paint sprayers
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KILZ Adhesion Primer, Interior/Exterior

KILZ is an excellent latex primer explicitly designed for sleek surfaces where the standard oil and water-based products won’t adhere.

It bonds paint to surfaces like PVC, fiberglass, metals, or surfaces painted with glossy paint. This primer is versatile, and

you can use any paint over them, including epoxies, lacquers, or even products that contain Xylene or other solvents.

Since it’s water-based, this KILZ Adhesion primer dries fast. It takes 30 minutes to dry to the touch and becomes ready for a recoat in one hour.

One gallon of this primer can cover approximately 300 sq ft of space; therefore, you won’t need too much of it to complete large projects. Additionally, you can use it either indoors or outdoors and use a brush, roller, or sprayer to apply it.

On the downside, this product doesn’t work well on floors, horizontal surfaces, or any surface in constant contact with moisture.

Image of A wood PrimerPros

  • It helps paint bond to hard-to-paint surfaces
  • It is water-based; therefore, it dries fast
  • 1 gallon can cover enough space
  • You can use it indoors or outdoors


  • It doesn’t provide moisture protection.
  • It doesn’t work well on floors or horizontal surfaces.
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Can You Leave Primer Unpainted?

You cannot leave primers unpainted because manufacturers did not design them for use as topcoats. Unlike paints, they cannot fend off damaging elements like water and UV rays for a long time.

If you leave the primer unpainted, the surface will get stained and damaged. These damages are usually impossible or hard to rectify; therefore, avoid the problem by painting over the primer.

For instance, if you’re painting a structure near a smoking zone, the smell of smoke will cling to the surface.

Even if you paint over it, the stink will still seep through. Pet odors can also linger on the primer, causing your space to smell terrible even after painting.

Additionally, primers are stickier than paint; hence, they easily attract dust particles and other debris. As a result, the primer coat will look dated, and the dust particles will hinder paint adhesion when you finally apply it.

If you wish to leave your primer unpainted, I recommend that you apply a clear protective coat over it. The clear coats are strong, just like paint; therefore, they will keep the primer undamaged for longer.

However, you should know that you will have to strip the primer and clear coat, reprime, then paint when you’re finally ready to proceed.

How Long Can You Wait Before Painting Over Primer?

The ideal time to paint over primer is when the manufacturer has indicated on the product’s instructions. You can paint over most primers after 24 hours, but there are a few special ones that you can paint over in as little as 6 or 12 hours.

If you have a big job and you can’t paint in the time recommended, you can leave the primer bare for a few days up to a week.

However, one week is also a stretch; therefore, you must be careful not to leave the primer for too long. Otherwise, you will have to reprime the surface. But how long is too long?

Most primers give you a window of 30 days to paint, but this time varies depending on your product.

Therefore, ensure that you check the manufacturer’s recommendation of how long you can leave their product uncoated without repercussions.

If, due to unavoidable circumstances, you happen to leave your primer unpainted for more than 30 days, use the following methods to salvage your project.

Apply a fresh primer coat over the old primer, then paint over it immediately after it dries.

If you do not have any more primer,  sand down the chalked-up parts of the coating, then paint over it. However, this method takes more effort, and your paint job won’t last long or look as good as expected.

How to Choose the Right Primer Type

Paint primers have a lot of important purposes – they help the paint stick to the surface, cover stains, and some even fill minor cracks in the surface.

Because of these crucial roles, you must find the right kind of primer for your particular project to achieve great results. So how do you go about it?

Choosing a suitable primer requires you to do three main things:

  1. Identify the type of surface you want to paint: wood, metal, glass, concrete, etc.
  2. Assess the issues you need to tackle to determine the severity of the problem. This means checking for odors, stains, wood knots, etc.
  3. Finally, look out for any issues that may require special treatment. Check if there’s mold, or if the surface already has paint on it, etc.

Once you understand these, it will be easy to pick out the perfect primer type. So let’s see how to go about that.

Surfaces With Stains and Odors – Stain-blocking Primers

Most surface stains bleed right through primers and paint, no matter how many layers you apply. Even odors from fires and cigarettes seep through eventually. The solution for these is to purchase stain-blocking primers.

These primers are available as oil-based, water-based, and shellac-based. You can select whichever you want, but I recommend the shellac types because they cover even the most stubborn stains.

The oil-based versions are a close second, followed by the latex primers, which sometimes allow odors to seep through them.

New Drywall – Drywall Primer-Sealers

The mud builders use on the seams of drywall absorbs paint at a different rate than the rest of the drywall. As a result, the color will appear blotchy because it is dull in some areas than others – a problem called flashing.

It also causes an inconsistency in the paint sheen, which will make your wall look ridiculous. Therefore, when you purchase a primer, look for products labeled as “drywall primer-sealers,” and your problem will be sorted.

Moisture Prone Areas – Waterproofing Primers and Mold Resisting Primers

High moisture in places like kitchens and bathrooms causes many problems with paint adhesion. The humidity also contributes to the growth of mold and other fungi, which leave bad patches all over the place.

Use waterproofing primers to keep the moisture away from the surface in such places. Also, look for products formulated with biocides that will kill the fungi and prevent them from regrowing. It is even better if you find a primer that has both properties.

Sleek Surfaces – Adhesion Primers

Paint always peels off sleek surfaces like plastic and glass in a short time. Therefore you need to treat the surface with a good adhesion primer or a primer with great adhesion capabilities.


Kilz and Zinsser are the most popular primer brands on the market today. They perform similar functions and have almost identical properties, so differentiating them is challenging.

I put together this extensive comparison between Kilz Vs. Zinsser to help you know which is best for your project.

Zinsser primers are best if you want adequate bleed-through protection because they are thick and durable. However, their thickness also makes them hard to stir and apply.

On the other hand, Kilz Products have a lighter consistency and offer adequate surface coverage, but they don’t provide good bleed-through protection.

The Kilz Products are more budget-friendly than Zinsser’s but not by a significant margin if you’re looking at cost.

I hope that I have cleared up everything for you. If you have any queries or more information to share, please reach out in the comments section.