Varnish Dry Time (Oil & Water-Based): How To Speed It Up?

A varnish coat will protect a wooden surface. But, varnish has to dry and cure before it can protect a surface. So, how long does varnish take to dry?

Varnish takes between 6-24 hours to dry. On average, water-based varnish takes 6 hours to dry for a re-coat and 72 hours to cure. In comparison, oil-based varnish takes 24 hours to dry for a re-coat and 1 week to cure. 

However, the ambient temperature, humidity, type of wood, and the number of varnish coats determine the varnish dry time. For example, if you apply varnish at a humid and cool temperature, it takes longer to dry. 

Varnish Dry Time Between Coats

How Long Should Varnish Dry Between Coats?

Varnish must dry at least 6 hours between coats. The dry between coats means how long to wait before you apply another coat of varnish (re-coat).

Water-based varnish dries faster than oil-based varnish. On average, water-based varnish dries enough for a re-coat in 6 hours, while oil-based varnish takes 24 hours to dry between coats. 

The reason water-based varnish dries faster is because of the solvent. Water-based varnishes use water as the solvent, while oil-based varnish uses natural or synthetic oil. Since water evaporates faster than oils, the water-based varnish will get dry quicker than the oil-based varnish. So you can re-coat quicker.

To know if varnish is dry enough for a re-coat, feel the texture of the finish. If varnish feels sticky to the touch or gummy on the fingers, the varnish hasn’t dried enough.

You can also know if varnish is dry enough by using fine-grit sandpaper. Swipe fine-grit sandpaper over the varnished surface; if the sandpaper clogs up with varnish, the varnish isn’t dry enough. If the sandpaper moves smoothly over varnish, the varnish is dry,

Or, you can check the varnish container to know the exact dry time between coats.

Related Read: Polyurethane Dry Time?

Varnish Cure Time

How Long Does It Take Varnish To Cure?

It takes varnish between 24 hours and 1 week to cure. Water-based varnish cures within 24 hours, while oil-based varnish takes 5 days to 1 week to cure. However, you must leave oil-based varnish to cure and harden for 1 week before use. 

The cure time of varnish depends on the temperature and humidity. The curing process of varnish is based on oxidization, while the drying process is based on evaporation. 

For varnish to cure, the dry air (oxygen) has to get into the varnish and cause the paint particles to oxidize and harden. After the paint particles become hard, the varnish cures. Once the varnish cures, you can sand, clean, and use it. 

You can damage the finish if you clean or use varnish before it has cured. If the paint particles aren’t hard enough, the finish will be weak. You can remove a weak varnish coating by sanding or using water. So, always wait for the varnish to cure before using it.

How To Speed Up Varnish Dry Time?

How To Speed Up Varnish Dry Time?

This guide will show you; 5 methods to make varnish dry faster, the tools you need, and how to do each method. 

1. Using A Hairdryer

You can speed up the drying time of varnish using a hairdryer. Hairdryers generate a temperature over 100 F. Here’s how to do it:

  • Turn on the hairdryer.
  • Set the heat to medium.
  • Hover the hairdryer around the varnish coating for a few minutes.
  • Crank up the heat.
  • Move the hairdryer over the varnish one last time.
  • Turn off the hair dryer and let the varnish dry for about 4 hours before recoat.

You shouldn’t fully dry the varnish using a hairdryer. If you do, the paint particles won’t harden naturally, so the finish will peel off. Instead, use a hairdryer to speed the drying time just a bit. 

2. Using Paint Thinner

You can use a paint thinner to make varnish dry faster. This works for oil-based varnish, and you must do it before applying varnish. Oil-based varnish takes longer to dry because it has a thicker coat. So, if you thin varnish and apply lighter coatings, the varnish will dry faster. 

To thin oil-based varnish, use turpentine, mineral spirits, or paint thinner. To thin water-based varnish, use water. 

Here’s how to do this:

  • Get a clean paint bucket.
  • Pour the varnish inside the bucket.
  • Add paint thinner to the varnish (you can thin the varnish up to 50%).
  • Stir the paint thinner and varnish for 90 seconds (stir gently).
  • Test the varnish on a small area on the wood to see how it dries.

You shouldn’t over-thin varnish because the finish will be inconsistent and weak. 

3. By Improving Air Flow

Since varnish dries through evaporation, you can increase the evaporation rate to speed up the varnish drying time. To increase the evaporation rate, you must improve the airflow around the varnish coating. Improving air flor also makes varnish cure faster. 

Here’s how to do it:

  • Open all windows, doors, and air vents.
  • Turn on the fans and direct them toward the varnish.
  • Set the air conditioner to “blow” or “fan.”

The increased airflow will cause the paint solvent to evaporate faster and for varnish to oxidize.

Here are a few rules and tips to remember while applying varnish:

  • Turn on the dehumidifier to reduce moisture content in the air.
  • Only apply varnish if the ambient or room temperature is above 60 degrees.
  • Only apply varnish when the humidity is at or lower than 50%.
  • Don’t apply varnish during the cold winter months.
  • Thin the varnish before applying it.
  • Apply light coats of varnish.

Different Types of Varnishes and Their Dry Time?

Different Types of Varnishes and Their Dry Time?

Here are some different types of varnished and their dry time explained:

Spirit Varnish

Spirit varnish dries in less than 24 hours. Spirit varnish dries faster than oil-based varnish because spirit varnish has no oils in its formula.  The varnish is made from resin, solvent, and alcohol. 

But, spirit varnish takes longer to cure. It takes spirit varnish 5 days to 1 week to cure. 

Acrylic Varnish

Acrylic varnish dries enough for a re-coat within 12 hours. Acrylic varnish is water-based and has one of the fastest dry times among other types of varnishes. It takes acrylic varnish between 6-24 hours to cure. That’s because acrylic varnish contains a low amount of oil in its formula. 

Exterior Varnish

Exterior varnish dries enough for a re-coat within 24 hours. Exterior varnish is formulated with extra oil and chemicals to reinforce the varnish to thrive in harsh exterior environments. The extra chemicals and oil make the exterior varnish thicker and increase its drying time. 

Exterior varnish air dries, meaning the varnish dries based on exposure to dry air. Since exterior varnish is used outdoors, the varnish is exposed to a lot of dry air, so exterior varnish dries to touch fast. But, even when the varnish is dry to touch, it’s still not strong enough to hold another coat. Therefore, you must wait 24 hours before re-coating exterior varnish and 1 week before exterior varnish cures.

Polyurethane Varnish

On average, polyurethane varnish dries enough for recoat in 24 hours, and the varnish cures in 3 days. 

Polyurethane varnish is oil-based, so it takes longer to dry. Also, polyurethane varnish is a combination of two slow-drying finishes; polyurethane and varnish. 

Normal polyurethane takes a few hours to cure. But, when you combine polyurethane with varnish, the dry time increases. But, polyurethane varnish offers great protection features. 

Varnish is Dry When:

The following signs will indicate when the varnish is dry enough:

  • When the varnish is no longer sticky or tacky.
  • When the varnish no longer smells.
  • When the varnish is hard.
  • When you can sand the varnish without the sandpaper slowing down or clogging up.
  • When the varnish looks shiny and not wet.
  • When the varnish reveals the wood grain.
  • When the varnish causes water to bead.

The varnish is dry enough to recoat and even sand when you notice these signs.

Final Words

Depending on the type, varnish can take several hours to days to dry and cure. Oil-based varnish takes 24 hours to dry, while water-based takes 6 hours to cure.

So, if you want a quick-dry varnish, use water-based types. Also, always leave varnish to cure for at least 3 days before using it.

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