How To Thin Paint

Thinning paint is a simple process that can make a significant difference in the outcome of your project.

Paints come in two categories: oil-based paint and water-based paints, known as latex paint.

Water, medium, acetone, turpentine, flow-aid, or paint-thinner can all be used to thin paint when the paint is too thick.

You should use a 4:1 paint-to-thinning-agent ratio, applying small amounts and gradually thinning until you get the desired paint viscosity for a smoother finish.

Acrylic paint thinning

To avoid it becoming runny or too diluted, you should always have a higher concentration of paint than paint-thinner.

Your paint will dry with air pockets, bubbles, easily chip away and create an unpleasant texture to your project if you don’t have the paint consistency.

In our guide, you can learn more about how to thin paint, how to thin paint for sprayer, and how to use water for dealing with paint that is too thick. (Find the Best Waterproofing Paint)

By the end, you’ll find thinning the paint is much easier than you thought for all your DIY projects as long as you change the paint in small increments.

What Can You Use to Thin Paint?

You’ll find many types of paint that require thinning, and the amount of thinner you add varies based on the type of paint you have and your application.

Although you can have old paint, you need paint to flow freely when using a spray gun.

Here are the various thinning process types you’ll find that are most common.

How to Thin Latex Paint?

Because latex paint is relatively thick, you’ll need to thin it before utilizing a handheld spray gun, HVLP sprayers, or airless paint sprayers.

Thinning paint is fairly straightforward; you can use water to do it. Add your paint to a measuring cup and stir it with a stir stick or something suitable. Here are the complete steps to thin paint for spray painting.

  1. Open the paint container and thoroughly mix your paint. Paint stores can mix this on a machine if you purchase it).
  2. Pour the required amount of paint into another container or large bucket. (Pouring more than you need will thicken it again if you leave it standing).
  3. Each time, use a quarter cup of water as this can allow you to thin your paint without it becoming too runny. (Slowly add a small amount, and you can control the viscosity).
  4. Stir the paint and water, then test the consistency.

Once you mix the paint and water each time you fill your gun, you’ll learn the proper amounts. The consistency needs to be consistent, or you’ll suffer from patchy paintwork you can quickly see on a large surface.

You’ll often need a second coat, and the drying time could be longer with more water in your paint.

The viscosity of the paint must be appropriate for the application, which is why it’s critical to test.

  1. Pour the paint into your bucket through a funnel; once it is correct, it flows freely.
  2. Fill your spray gun halfway with paint to test it on an old piece of cardboard.
  3. If it is still too thick, return the paint to your bucket and add more water.
  4. Repeat the thinning process until you reach the desired consistency for your paint job.

Thin Paint using Spray Gun

Thin Paint for Spray Gun

Latex paint should be thinned at a rate of at least 10%, or 1 gallon of paint to 1/4 cup water.

If you’re not using an airless sprayer, you’ll need to do this. If you’re using an HVLP sprayer or a hand-held system, your water percentage may need to be increased to 20-30%.

Thinning Acrylic Paint for Spraying

Because acrylic paints are water-based, they are simple to thin. When thinning paint for a sprayer, you’ll want to be careful not to add too much, as it is hard to add more paint to the mix.

Too much water interferes with the ability to adhere and causes your paint to flake. When using acrylic paints on an absorbent surface, you can use up to 50% water; however, when using on other surfaces, maintain the percentage below 30%.

Thin Oil-based Paint for Spray Gun

Oil-based paints, such as semi-gloss enamels, must be diluted before use. Oil-based paint is slightly thinner than latex paint, but it still needs to be thinned for the best effects. Always check the manufacturer’s label for the maximum thinning ratio before thinning your paint.

Also, check the label to see what type of thinner you can use because oil-based paints require something other than water. The amount of paint that needs to be thinned is usually 10%; add a half cup of room temperature water for each gallon of paint.

However, three factors influence this:

  • Application – It could be wooden furniture, interior walls, or exterior walls
  • Specific coating
  • Type of oil-based paint sprayer

How Do You Thin Out Paint at Home?

Here are some different ways to thin paint for different types of paint sprayers.

Paint Gun with HVLP for Tin Paint

Paint Gun with HVLP (High Volume, Low Pressure)

This is mainly used as a paint sprayer for oil-based paints, although you can use them for latex paints and indoor applications.

The paint needs to be diluted somewhat, so start with 10% water and gradually add more until you get the desired consistency.

Water-based paints, such as latex can also benefit from the use of a paint conditioner. This makes the paint easier to spray without thinning it out, and it does not affect the paint’s adhesion to the surface. (Learn How To Fix Chipped Paint On Wall)

Airless Spray Gun

Latex paints perform well with airless spray gun systems, and some don’t even need to be thinned before spraying. You can use the paint right out of the can. When spraying paint that hasn’t been diluted, the airless technique has some restrictions.

Some of the larger systems can spray unthinned paint, while smaller, less expensive systems will require thinned paint to function correctly.

You can go for 20% water to thin the paint, and the paint should spray fine. However, if you use an airless system to spray oil-based paint, the paint is not thinned before application.

Is it OK to Thin Paint with Water?

Working with latex paint has several advantages, one of which is its ease of use. Latex paint is ready to use as soon as you return it from the store in mixed form.

New, freshly mixed latex paint rarely needs to be diluted for most paint roller and brush applications. Paint producers create latex paint with a viscosity that is suitable for a wide range of uses. Because “average” may not apply to all situations, you may need to thin latex paint for applications like paint sprayers or for older paint that has lost some of its water content due to evaporation.

What You Need

  • Cordless drill
  • Metal spiral power mixer
  • Paint stirring stick
  • Rubber gloves
  • Measuring cup
  • Viscosity cup and fine mesh cone strainer (both are optional)


Acclimate the Paint

Acclimate the paint to room temperature between 50 and 90 degrees Fahrenheit before you thin it.


Insert the power mixer attachment into the drill and thoroughly mix the paint.

To test the paint, run the wood stirring stick through it. The solids haven’t entirely blended if the stick drags at the bottom. If so, shake the can with the power mixer until the paint is uniformly thick from top to bottom.

Buy a small, low-cost viscosity cup for precise calibration when using a paint sprayer.

Alternatively, dip some paint in a clean disposable cup and pour it through a kitchen funnel to test viscosity. Thicker paint will clog the exit hole or cause it to drain slowly.


Solid paint and skin can develop and can’t be restored by thinning with water. Pull out bigger pieces using the hook end of a paint can opener. Remove smaller pieces using a mesh cone strainer.


Use a fluid measuring cup to portion the precise quantity of water. The volume of water depends on the paint’s consistency and the consistency you want.

Start with 4 ounces of clean, room temperature water, then add as required. Thinning paint for spraying and manufacturers limit the quantity of water to 8 ounces per gallon of latex paint.

Slowly pour the water into the paint while gently stirring the paint with the wood paint stick. Test with the viscosity cup or funnel before use.

Tips for Thinning Latex Paint

Never thin water-based latex paint with petroleum-based materials. Any product marketed as mineral spirits or paint thinner is almost certainly a petroleum-based solvent.

Consider using a paint additive instead of water to eliminate brush or roller markings. Add 8 ounces to roller and brush applications.

When you add water to paint, it dilutes it and lightens its color, so you may need to apply more coats to improve the color quality.

When the lid of the can is encrusted with paint, it means the latex paint has lost water due to evaporation. Water-based paint can evaporate even if there is a pinhole-sized space between the lid and the can. (Learn When To Remove Painters Tape)

Replace the crusted lid with a tight-fitting plastic pour-and-store kind of lid or pour the paint into a sealable paint can with an airtight seal to prevent evaporation.

How to Thin Oil Paint

  1. Wear gloves as you can easily stain your hands.
  2. Oil paint thinning differs from latex paint thinning as there are extra steps in the paint thinning process.
  3. In a big container, pour oil paint.
  4. For every three parts of paint, add one part turpentine.
  5. Stir the paint around for several minutes with a stick until entirely mixed. Check the consistency and stop when the paint’s viscosity appears creamy.
  6. Hold the stir stick over a paint tray or a paper plate after removing it from the paint can. The paint is the correct consistency if the paint runs quickly from the stir stick.
  7. During the mixing step, there may be some trial and error. If the texture isn’t what you’re looking for, gradually add thinner to the paint bucket.

How To Thin Paint

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