It’s always advised to prime before painting but before you can paint over primer, the primer coating has to be dry. So how long does primer take to dry?
It takes primer between 30 minutes and 6 hours to dry. On average, primer will dry enough for the top coat 2 hours after the primer coating was applied.
Many manufacturing brands advise waiting at least one hour before painting over primer. Water-based primers dry quicker than oil-based primers because water evaporates faster than oils from the primer coating.
Dry Time Between Coats of Primer
You should let the primer get dry and hard before you apply the second coat. On average, this will take 60 minutes after the existing coating was applied.
For water-based or latex primers, this can take less than 60 minutes as these primers are based on a quick-dry solvent; water. For oil-based primers, it can take well over 2 hours before you can apply a second coat of primer.
If you apply a second coat of primer without the first drying properly, you’ll end up with the same result as if you paint over the primer too soon. The finish will be weak and messy.
Also, the second primer coating will not bond well to the existing one. This will cause a weak foundation that can cause the entire paint coating to fall off.
Don’t Apply a Paint Coat Too Soon
If you paint over primer too soon, the paint will not bond properly to the primer since the primer will still be wet. This means the paint adhesion will be weak and this can cause the entire paint coating to peel and tear. If the paint is on a vertical surface like a wall, it will fall off the surface if you paint over the primer too soon. That’s not all.
If you paint over primer too soon, the finish will be riddled with stained spots. This is because the moisture in the primer coating will bleed through the paint causing dark and stained spots. Painting over primer too soon can also damage the material especially porous material like wood.
If you paint too soon you will be wasting the paint. To top it all, you’ll also end up with a very poor finish in terms of color and durability. Instead, wait for enough time to allow the primer to dry. So how long should you wait for the primer to dry between coats? Let’s find out.
Factors That Determine Primer Drying Time:
The Type of Primer
There are different types of primers — latex, oil-based, shellac, and self-priming. Each of these primers has a different drying time. That’s because these types of primers have a different formula each.
- Water-Based Primer (Latex) – The water-based primer is a fast-drying primer. The reason for this is that it doesn’t have a complex formula and the water evaporates faster. Water-based primer dries within 1 hour.
- Oil-Based Primer – The oil-based primer has a more complex formula than the water-based primer. Instead of water, the oil-based primer has oil as its solvent. Oil takes longer to evaporate, and therefore oil-based primer has a longer drying time. Oil-based primer dries within 2 hours.
- Shellac Primer – If you want a stain-blocking primer then shellac primer is the one. Shellac primer is also good for covering any musty smells and sticks to almost any surface without sanding. Shellac primer dries within 1 hour.
- Self-Priming – The self-priming primer has paint and primer in its formula. It’s a great choice if you want to save some time. Self-Priming primer takes around 1 hour to dry.
The thickness of the primer coat determines how long it takes primer to dry. If the coat is too thick, the primer will take longer to dry because the evaporating will happen slower. If you apply thin coats of primer, the primer will dry faster.
The number of coats is also important — the more coats you apply, the longer primer takes to dry. You will have to wait each coat to dry before you add the next one, and that adds to the total amount of time you spend completing a project.
The temperature and humidity levels can speed up or slow down the primer dry time. If the humidity levels are too high the primer takes longer to dry. The humidity levels should be between 50-60% for the primer to dry properly.
The temperature also determines the primer drying time. If the temperature is too low, the primer will take longer to dry because the evaporating process is slower on cold days. If the temperature is too high, the primer will dry too quickly but it may chip off later because the paint particles aren’t bonded naturally.
The temperature should be between 40-80 °F for the primer to dry properly.
How To Make Primer Dry Faster?
There are a few ways to speed up the dry-time of paint primer. The first one is:
1. By Using A Hairdryer
Hairdryers generate heat as high as 300 degrees F. If the primer coating is exposed to such a level of heat, it can dry twice as fast. To use this method, you’ll need a hairdryer.
Here is a quick rundown of how to use a hairdryer to make primer dry faster:
- Plug in and turn on the hairdryer.
- Set the heat to medium (between 120 and 180 degrees).
- Move the hairdryer over the primer coating.
- Crank up the heat by 20 degrees F.
- Turn off the hairdryer after 10 minutes.
Let’s check out another method.
2. By Improving Ventilation
Most primers air-dry which means the primer will dry faster if exposed to cool air. To use this method,
- Turn on the fans.
- Open all doors and Windows.
- Open the air vents.
- Switch the air conditioner to fan or blow mode.
3. By Using A Dehumidifier
High humidity or moisture level in the atmosphere means the primer will take longer to dry. This is very common when you paint during cold weather or the cold winter months.
A dehumidifier can help to reduce the effects of humidity on the primer coating. For this method, you’ll need a dehumidifier. The dehumidifier will draw moisture from the air and release dry air in the process.
So how do you know when the paint primer is dry enough.
Related Read: Can You Prime Over Peeling Paint?
Dry Time For Different Types of Primers
The type of primer, the number of coats, and environmental conditions all determine how long it will take for the primer to get dry.
There are also different types of paint primers — some dry quicker and some slower than others.
It takes wood primer between 30 minutes and 2 hours to dry. Wood primers dry quicker than most types of primers. Two major reasons make wood primer dry quickly.
The first is because most wood primers use water as their solvent. Since water evaporates quickly, the primer coating will get dry quickly too.
The second reason is that wood primers are usually stain-blocking sealers and most of them have shellac in the paint formula. Shellac is a quick-dry stain-blocking and moisture-resistant additive that makes primers prevent bleed-through. Since shellac dries fast, the wood primer will too.
The third reason is that wood primer “air-dries.” Air-drying primer dries as it comes in contact with dry air which is basically what’s in the environment. So immediately after you let go of the final stroke of the brush, the wood primer begins to dry.
Since the wood primer is water-based, it air-dries, and it contains shellac, it will dry quickly. On average, Wood primers dry enough to be painted over 1 hour after the primer coating was applied.
However, the environment in which the wood primer was applied also affects how long it takes to get dry. If the wood primer is applied in a moist condition, it will take longer to dry as the level of humidity will be high making the paint wet.
The type of wood also affects the primer’s dry time as some wooden materials are more porous than others.
It takes spray primer between 1 and 6 hours to dry. On average, spray primer can be painted over 2 hours after the primer coating was applied.
Spray primers generally take longer to dry because they contain additives like glycerin, glycol, and plastic resins. These additives are included in the paint formula to improve the quality of the primer coating. But, they also increase the dry time of the primer coating.
Spray primers that have plastics in the paint formula also take longer to dry. Spray primers can take up to 6 hours before being dry enough to be painted over. Some spray primers also dry quickly but these primers are usually latex or water-based.
Kilz primer takes 15 minutes to dry but sometimes, it takes over an hour to be ready enough for a top coat. This is because there are different types of Kilz primer.
Kilz exterior primer for instance takes longer to dry than Kilz interior primer. However, most Kilz primers will dry in less than 30 minutes.
The reason for this very fast dry time is because Kilz is a water-based primer which means the primer coating will dry fast. You can check the container of the Kilz primer that you buy to know how long it takes for the primer coating to dry.
It takes between 30 minutes and 4 hours for the epoxy primer to dry. On average, the epoxy primer will dry in less than 2 hours after the paint was applied but the dry time is largely dependent on the weather conditions.
If the weather is cool, it will dry slower than when the weather is warm or hot. This is because the epoxy primer is more affected by the ambient temperature than any other primer.
Since epoxy primer is designed for steel or metal, the primer will take longer to cure. That’s because it will take a long time for the primer coating to bond to the slick steel surface.
So asides from a long dry time, the epoxy primer will also take longer to cure which means more time to wait before applying the top coat.
Outdoors vs Indoors: Dry Time
There’s a difference between the exterior and interior drying time of primer:
It takes between 30 minutes and an hour for primer to dry outside. This is because the primer coating will be exposed to cool air from all angles. Primer coating will also be exposed to direct sunlight and heat making the rate of evaporation faster. This will make the primer coating dry quickly.
However, exterior primers (primers designed for outdoor use) can take longer to dry outside. This is because these primers are usually designed with additives like UV blockers to help the primer coating thrive in the harsh exterior environment. Since these additives add to the volume of the paint primer, the primer will take longer to dry.
During cold weather, paint primer will take forever to dry outside. This is because the atmosphere will be very moist. So if you plan on applying primer in the winter, don’t.
Primers take longer to dry inside than outside. This is because the primer coating isn’t exposed to as much cool air. Also, the primer isn’t exposed to direct sunlight or heat. This means that the primer will dry slower. On average, paint primers dry within an hour inside.
However, you should know that during the cold winter months, primer will dry faster inside than outside. That’s because the primer coating inside is shielded from moisture.
How Long Should Primer Dry before Painting?
When the primer coating is dry, hard, and smooth, it has dried enough and can be painted over. On average, this will take 60 minutes. It can take longer if the primer is oil-based. If the primer is still soft or wet, then the top coat will not sit properly and this will cause a weak and poor finish.
To know if the primer is dry enough to paint over, try to dent the primer coating with your finger. To do this, push a finger in the primer coat gently. If you see the primer color on your finger, it means the primer is still fresh.
Dry primer will not come off on your finger. Also, if you can create a dent in the primer coating, it means the primer shouldn’t be painted over yet. Dry primer will be very hard to dent with your finger.
How Long Can You Leave Dried Primer Un-Painted?
You can leave the primer sit for about 24 hours before you paint over it. If you leave a primer that is fully dried sit for more than 24 hours then the paint may not stick. Dust and dirt will start to assemble over the primer coat.
The more dust and dirt the primer has on its surface the more it will block paint from sticking. If have to leave the primer sit for more than 24 hours, then make sure to clean the surface with a TSP cleaner before you apply paint.
Why Isn’t Primer Drying?
When primer doesn’t dry properly it will turn sticky or tacky. The reason primer won’t dry is because you re-coated too soon or you applied primer on a wet surface. To fix primer that won’t dry, you can use a hairdryer or heater.