How to thin enamel paint for spray gun?

By Marko Jankovic | Last Updated: January, 2021

How to thin enamel paint for spray gun

Enamel paint is ideal for all kinds of paint jobs, making it quite popular. With enamel paint, you get an even, professional finish every time. However, enamel paints are somewhat thick to use with a spray gun without thinning.

Understand that without proper thinning, you will get mediocre results. In this article, I will walk you through a step by step tutorial on how to thin enamel paint for spray gun. Well, let’s get started so you can get painting.

Understanding enamel paint

Before we can start painting using enamel paint, you need to understand everything about this type of paint. By definition, enamel paint stands for solvent-based paint that gives you a hard, glass-like shell finish.

This type of paint is an excellent choice when dealing with patio furniture, stairs, and house trims. Most people use them for outdoor painting since they are quite durable. Before you start using enamel paint, ensure that it is best suited for the project.

Types of enamel paint

Enamel paints are traditionally oil-based, thus giving you that smooth, long-lasting finish. However, there has been an increased demand by the public for non-toxic paint alternatives. Which brings us to the water-based enamel paints that are now quickly becoming popular.

Understand that water-based enamel paints are simple to work with because they dry faster, and are easy to clean. The oil-based enamel paints, on the other hand, last longer and provides a much smoother finish.

Choosing between oil-based and water-based enamel paint

The choice between water-based and oil-based enamel paint comes down to customer preference. You get to decide which between the two best suits your project. The water-based paints are great for essential projects in the home. Heavy-duty oil-based paints can withstand harsh outdoor conditions and constant wear.

Thinning enamel paint for spray gun

Once you decide which type of enamel paint is best suited for your project, we can start the thinning process. As a rule, water-based enamel paint will need water for thinning, and oil-based enamel paint will require mineral spirits.

Ensure that you follow the instructions on the label of your enamel paint. These instructions will help you determine the amount of thinner that your product needs.


  • Respirator
  • Paint stirrer
  • Safety goggles
  • Paint strainer
  • Bucket
  • Boards
  • Spray gun
  • Water or mineral spirits

Step 1: Safety first

Before starting any project, the first thing that you need to consider is safety. In our case, you will need safety equipment, including a respirator and goggles. The safety equipment is to protect you during the entire project.

Understand that paints expel fumes that are flammable and toxic to your health. A dust mask is never sufficient protection when spray painting or airbrushing an enamel. Prolonged exposure to paint chemicals could lead to severe sickness and even death.

The spray gun atomizes the enamel paint, thus producing a mist filled with millions of microscopic particles. These particles can float in the air for a few hours before settling down. Using a respirator and safety goggles ensures that you safeguard your health.

Step 2:  Pour the paint into the bucket

Take your paint and pour it into the empty bucket. Place the paint strainer above the bucket before you start pouring your enamel paint. The paint strainer acts as a sieve that catches any paint impurities, including dirt, clumps, dried flakes, and dust.

Straining your enamel paint is a critical step that shouldn’t be overlooked. Using a spray gun will only get you that smooth, professional finish if your strain your enamel paint properly. The unwanted particles usually clog your spray gun and get you an uneven finish.

If you don’t want to repeat the entire project, ensure that you use a paint strainer. Place it on top of your empty bucket then pour the enamel paint. Dispose of all the filtered particles and clumps that get trapped by the paint strainer.

Step 3: Follow the paint-to-thinner ratio

As stated earlier, the label instructions should help you determine the amount of thinner that your enamel paint needs. Understand that there is no universal paint-to-thinner ratio that you can use. All these paints are different and unique.

In most circumstances, however, you will need one part thinner and three parts of the paint. The thinner, in our case, will either be mineral spirits or water. This depends on whether you have a water-based or oil-based enamel paint.

Note that the amount of oil-based paint should always be higher than the thinner. Adding too much thinner will lead to a lighter color shade than what you desired. Once you figure out the amount of thinner that you need, you can move on to step four.

Step 4: Stir thinner into paint

Use the paint stirrer to stir the require amount of thinner into the paint. Slowly pour the thinner into the bucket with the enamel paint. Use the paint stirrer consistently during the entire step. Be very careful to ensure that you don’t add too much thinner.

Stir the mixture thoroughly until you get a smooth finish with the same viscosity. Although a spray gun saves you a lot of time, you have to ensure that you use a smooth paint mixture. Without proper stirring, you might end up with different shades of color, which is not ideal.

Step 5: Pour the thinned paint into a second bucket

Pour the thinned paint into another empty bucket through a funnel or the paint strainer. This step should help remove any clumps that might have formed during the thinning phase. If the paint doesn’t flow through the funnel, then you need to add one more part of thinner.

Be careful when adding paint thinner because it could compromise the integrity of your finish. Too much thinner will also mean that it will take longer for the paint to dry.

What happens when you use too much thinner? Well, a simple solution would be to apply more coats of paint. Although the project will take more time than anticipated, applying extra layers will get you the protective coating and color you want.

Step 6: Testing

Pour a small amount of the thinned paint into the spray gun. Spray the paint onto one of the boards to check for consistency and ease. If the paint is easily sprayed and gets you a smooth finish, then you can start the project. However, if you encounter difficulties spraying the paint, then you need to add thinner to your paint. An uneven spray pattern also indicates that the enamel paint hasn’t been appropriately thinned.

Thin your paint a little more and test it out until you get a smooth, professional look. Once you are confident that your paint is correctly thinned, then you can start working on your project. Ensure that you wait for the paint to dry before applying a second coat.

Frequently asked questions and answers

Can acetone be used to thin oil-based enamel paint?

Yes, acetone can be used for thinning oil-based enamel paint. However, it is not recommended because it leads to several complications. Understand that acetone can dissolve surfaces such as plastic. Using mineral spirits is the most effective way of thinning oil-based enamel paint.

How much thinner do I need for enamel paint?

You need to check your paint container label for thinning instructions. Different manufacturers will recommend different thinner ratios. You should also add small amounts of paint thinner at a time to ensure that you get it right.

Should I thin all enamel paint?

Some enamel paints do not require thinning. Check the label to determine whether your paint requires thinning. Some enamel paints can be used with spray guns without needing any kind of thinning.

How to thin enamel paint for spray gun


Thinning enamel paint for a spray gun is a rather simple and straightforward procedure. Use the step by step guide to ensure that you get a professional finish. Do not start the thinning process before reading the label on your enamel paint.

About the Author admin

Leave a Comment: