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How to Thicken Paint: Getting the Right Consistency for Stellar Results

how to thicken paint hdr

Do you know that feeling you get when you open up a paint container only to find the contents are all runny?

I’ve been there, and let me tell you, it’s not fun.

No matter what type of paint you’re using, there’s always the risk of it turning into a thin, liquidy mess.

Because I know how frustrating it can be, I decided to put together a list of tried-and-true tips on how to thicken paint.

I’ll also walk you through some possible reasons why it’s happening in the first place.

Whether you’re a seasoned painter or just learning the ropes, these techniques are sure to come in handy.

They certainly have for me.

Let’s get started.

Reasons Why Your Paint Has a Watery Consistency

Below are some of the most common reasons why paint turns liquidy.

Paint Hasn’t Been Used for Some Time

Sometimes it could be that paint containers have been sitting idle for too long.

This is true for almost all types of paint; the longer they sit, the more liquidy they become.

With oil paints, however, it’s a bit different. Since oil is less dense than water, they’re known to separate after some time.

So, when it comes time to open up the paint container, you’ll notice it’s more watery than usual.

Paint Has Gone Bad

bad paint

Any type of paint has a use-by date. For example, unopened paint can last up to 10 or 15 years, depending on the type.

On the other hand, open paint cans last only a couple of years.

So, if you have opened paint containers that have been around for several years, chances are they’ve gone bad.

Besides being runny, another way to tell whether or not the paint has expired is its sharp, rancid smell.

It gets worse:

Expired paint may also be lumpy or have chunks. Some even become this solid, gooey consistency.

When this happens, your only option is to throw it out and replace it with new ones.

A Bad Batch of Paint

There might be times when your newly purchased paint is runny.

What’s up with that?

Well, the reason could be you just happened to buy a bad batch of paint.

It’s pretty rare that paint manufacturers will let a bad batch go slip by unnoticed.

Yet, there’s always that off chance it might happen.

Improper Storage

Improper paint storage

When you, or the paint store, stores paint containers the wrong way, it affects their consistency.

The result? They become too watery to use.

For example, leaving them exposed to direct sunlight can make them thin and runny.

The same goes for icy cold weather. Because paint doesn’t do well in the cold, it’ll just turn into a solid, gooey blob.

You might be wondering:

‘Can I freeze paint?’

That depends on how long you plan on putting your paint in the freezer.

If it’s only for a night or two, then there’s no harm in freezing any of your paint.

Longer than that, however, and you’ll have a problem on your hands.

For one, the icy temperatures will cause irreparable damage to the emulsion.

Once that happens, there’s no way you can salvage it and make it usable once again.

Now, here’s the kicker:

A friend of mine used to put their paint cans in the freezer to make them last longer.

Needless to say, when the time came to reuse the paint, it was stringy and clumpy.

In the end, she threw all the paint out and had to buy new ones.

Steps for How to Make Paint Thicker

tips to make paint thicker

Take it from someone who’s had a few run-ins with watery paint; it’s no picnic.

Now, here’s the good news:

Once you know why your paint is runny, you can easily restore it to its former glory.

1. Prepare Supplies

Here’s a quick list of the things you’ll need before we get started.

  • Wooden stirrers (you know, the classic ones that have been around forever)
  • Drop sheets to protect the floors
  • Plastic buckets or containers
  • Paint thinners for oil-based and latex paints
  • Dry mediums like flour, cornstarch, salt, sugar, marble dust, sand, or sawdust

2. How to Thicken Paint for Every Type

thicken paint tips

Whatever paint type you’re using, I’ve got the best method to give it a better, thicker consistency.

Latex Paints

The easiest way to thicken latex paint is to open up the container and allow the water to evaporate.

It’s simple enough, but it takes time. So, I recommend doing it several days before starting the actual painting.

The second way is to use a thickening agent, like HEC. It’s faster, but requires more work.

Hydroxyethyl Cellulose (HEC) is a widely used thickening and gelling agent.

Want to know the best part?

It’s water-soluble, making it the perfect thickening agent for latex paint.

You can buy HEC from any home improvement store. It’s also available here online.

Here’s how to thicken latex paint:

  1. Pour the paint into a large container or bucket.
  2. Slowly add the HEC, while constantly stirring.
  3. Wait a few minutes for the HEC to start taking effect.
  4. Test the paint on a flat surface to make sure it’s the right consistency.

Acrylic Paints

Tips to thicken Acrylic Paints

Most art supply stores offer paint additives specifically designed to thicken acrylic paints.

One brand that has worked well for me is Liquitex. It comes in a gel matte medium for a satiny, translucent finish.

Check it out here.

If you prefer, you can experiment with sawdust or sand. In small amounts, they can be exactly what your thin paint needs.

Marble dust is another great option. Find out more here.

Oil-Based Paints

Tips to thicken Oil Based Paints

Since oil paints tend to separate, they create a liquidy consistency. This is where paint thinners can help.

They thin out chunks of paint that sink to the bottom of the container and level out the texture.

So, how do you use paint thinners? Check it out:

  1. Pour the paint into a container.
  2. Add one part paint thinner for every three parts paint and mix carefully.
  3. Test the paint on a flat surface.
  4. If the paint is still runny, add one part paint thinner and try again.

Tempera Paints

Tips to thicken Tempera Paints

So, how do you thicken tempera paint? By using any of the dry mediums mentioned above.

First, add one tablespoon of dry medium to one cup of water in a pot. 

Put the pot on low heat and stir until everything dissolves.

When you get a smooth consistency, remove the pot and leave it to cool.

Finally, add the mixture to the paint until you get the thickness you want.

3. Preserving Paint

Here are common ways to keep paint smooth and consistent:

Tips to preserve paints

  • Always clean the rim of the lid
  • Place a layer of plastic wrap between the container and the lid
  • Secure the lid in place with a rubber mallet to avoid damaging the lid
  • Store the container upside down to reduce the amount of air
  • Keep paint in a cool, dry area

Smart Painting Tips to Keep In Mind

These tips will help ensure your paint is in the best shape to help get you the professional results you crave.

painting tips like a pro

How Do You Know if Your Paint Is Too Thin?

The easiest way to check whether your paint is too thin is by using a stirrer. Dip it in the paint for a couple of seconds.

If the paint drizzles and drips off the stick, this means it’s runny and too thin.

You can’t use it like that because it’ll cause inadequate coverage of the surface. Plus, applying it will only be messy and diluted down.

This is when using thickeners comes in handy.

Is Exterior Paint Thicker Than Interior Paint?

High quality exterior paint like from Sherwin-Williams, is meant to be thicker than interior paint, so it can stand up to the elements without peeling or cracking.

To make sure it’s the perfect texture, scoop some paint into a funnel. It should flow like heavy cream.

If it flows too quickly, that means it’s too runny and needs to be thickened. Alternatively, if it doesn’t flow freely, it’s too thick and needs to be thinned out.

Is Primer Thicker Than Paint?

Unlike paints made for exteriors, primer paint isn’t as thick as paint.

I like adding a coat or two on top of the paint job to seal the surface and protect the paint.

It’s supposed to be of a thinner consistency to help seal the surface.

In fact, experts recommend using a primer to give a smooth finish for the perfect paint job.

It’s worth mentioning that there’s something called self-priming paint.

It paints and seals the surface all in one, thanks to its high-quality resin.


I rounded up some of the most common questions asked by fellow DIYers just like you!

Do hair gel products make paint thicker?

No, they’re not designed to dissolve in water like paint thickening gels. So, they’ll just end up making the paint a sticky mess.

Do dry mediums change the texture of paint?

A medium is a substance that changes one of the paint’s features.

This means that when you add a dry medium to thicken your paint, it’ll affect one of its properties.

In this case, it’s the paint’s texture.

For example, if you add sand, the paint will have a bumpy, rough feel.

On the other hand, adding flour increases the paint’s coherence and makes it smoother.

Can I reuse paint thinners?

If you can reuse paint thinners, then, by all means, do so.

However, make sure they’re properly sealed and stored away in a safe place.


I hope you’ve gained some insight into how to thicken paint.

I wanted to bring all the options under one roof to see which option best suits your painting needs.

Now, all that’s left to do is enjoy creating your next artistic journey.

Happy painting!

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