Rustoleum is the most popular paint in several places, mainly due to its iconic rust-preventive property. While you can apply it with a paintbrush or roller like any paint, using a paint spraying gun is the quickest and most effective way to use the paint on most surfaces. 

Thinning Rustoleum paint is necessary if you want to apply it with a paint sprayer—in which case you need to know how to thin Rustoleum for spraying. 

This tutorial provides a step-by-step process for thinning Rustoleum paint, with suggestions of the thinner to use. 

What is Rustoleum Paint? 

This is an oil-based enamel paint currently ranking as the best product for rust-proofing metal surfaces, including cars, metal roofing sheets, ships, and more. Rustoleum paint can also be used on wood.

Rustoleum paint was invented by a sea captain in 1921. While the original formula contained fish oil, the product has undergone significant changes over the years and currently contains latex, polyurethane, epoxies, Alkyds, and more. 

How to Thin Rustoleum Paint for Spraying 

The best way to thin Rustoleum paint is to mix it with acetone in a large container or bucket. You can also mix the paint with mineral spirits or xylene in the ratio of 6 to 6.5 grams of thinner for every gallon of the paint. But first, know how much does a can of paint weigh first.

Consider using a viscometer or test the paint and add more of the thinner or paint as needed to get the correct viscosity for spraying. 

Below, we look at the thinning process step-by-step. 

What you will need

  • Bucket 
  • Stirring stick or dowel for mixing the thinned paint
  • Thinner (mineral spirits, acetone, or xylene)
  • Rustoleum paint 
  • Paint sprayer and nozzle(s)
  • Clean rag for wiping the nozzle
  • Paint funnel for decanting and transferring the product 
  • Measuring cup
  • Protective eyewear 
  • Safety face mask
  • Viscometer for measuring the viscosity if you prefer not to eyeball it
  • A piece of scrap metal or other test material (something similar to what you are painting)

Procedure for Thinning Rustoleum for Spraying 

Often, the manufacturer will recommend the thinner to use on your Rustoleum product along with the procedure to follow. While it helps to follow whatever the manufacturer recommends, there’s a tried and true procedure that applies to all the Rustoleum paints. 

Knowing and following these few simple steps should help simplify your work.    

Step 1: Stir the Rustoleum paint thoroughly 

Paint pigments typically settle at the bottom of the container. These are the colorants you want to target for your project, so you must redistribute them across the product before thinning it. 

The Rustoleum company recommends a way to mix the product. Start by pouring the separated liquid into a clean container, then use a stirrer to mix the remaining paint in the can. Thoroughly stir the product, paying attention to the paste accumulated on the walls and clomps at the bottom.

Ensure you break the clumps and incorporate everything inside the can to form one consistent product. 

Next, return the liquid you set aside at the beginning by gradually adding it back into the paint and stirring the mixture once more to incorporate it. 

To achieve a completely uniform consistency, we recommend pouring the paint back and forth between the two containers until you are happy with the consistency. 

Step 2: Transfer the paint into a bucket

Now that the paint is uniform transfer the amount you need to use into a bucket. Consider using a large bucket that can accommodate the paint together with the own thinning agent without running out of space for stirring. 

Step 3: Add thinner and mix

Use your measuring cup to add the x brand thinner into the paint at the ratio of six ounces per gallon of paint. Of course, this ratio can vary depending on our preference or the paint itself, but it shouldn’t be too far from this baseline. 

Additionally, you can always make any necessary adjustments to the thinned paint after testing. You will be testing it after adding the thinner and mixing it well.  

Step 4: Test the thinned paint

There’s no standard way to test the thinness of your paint that applies across the board. However, you can choose to eyeball it by applying it to a test object such as a piece of scrap wood, metal, or drywall. 

You could also run the thinned paint through a funnel and check its thickness. If you’re experienced with paints, you should be in a position to gauge the thinned paint’s consistency by observing its flow. If it flows freely, it should be adequately thinned and usable. Otherwise, you would need to add more of the thinning agent. 

Alternatively, you could test its thickness using a viscometer. The instrument measures the viscosity of a fluid by checking its internal resistance to flow.

All these are testing options available for you to choose from. Whatever you decide here is a personal choice. 

If you prefer to err on the side of caution, you can put some of the thinned paint into the sprayer and test it from there. This should give you a more realistic picture of what to expect of your final project. 

Place a funnel of the mouth of the sprayer and load it. Using a funnel helps ensure you don’t spill things around and create a dirty mess. From there, spray a section of your test material the same way you would on your actual project and observe. 

Step 5: Adjust if necessary 

If your test reveals that your paint has the correct consistency, your work is done. In other words, you want to check to ensure the paint comes out of the sprayer smoothly without any resistance. 

However, if the paint creates uneven coverage or comes out of the spray gun in splotches, it requires further thinning. You would have to add in more thinning solvent. In contrast, if the paint runs on the test surface, it’s too dilute and requires adjustment by adding in more paint.  

So, empty the paint in the sprayer back into the mixing cup and thin it further or add more paint depending on its condition. 

Once you achieve the right consistency, you can use a viscometer to note the correct ratio or note it down manually if you don’t have the equipment. This information may come in handy in the future should you want to repaint the project or complete another similar one. 

Step 6: Load the paint into your sprayer

Once you are happy with the viscosity of your thinned paint, it is time to load everything into the airless paint sprayer and proceed with your painting. 

Use the funnel to transfer the thinned Rustoleum paint into the tank of your sprayer. 

Different sprayers will have different use instructions. These can be found on the label or user guide that comes with your purchase. Be sure to read and follow these instructions for the best results and safe usage. 

How well you follow the instructions can directly influence your safety and the outcomes of your paint job. 

Additionally, ensure you wear the necessary protection when handling these chemicals. But, should you be unlucky, the paint spills; we have a guide on what gets spray paint off hands. Also, while spraying, hold the spray gun at enough distance to cover a decent area of the surface you’re working on while getting a good-enough coverage. 

And if you’re working on your furniture, here’s how to spray paint furniture with a spray gun.

What is the Correct Rustoleum Thinning Ratio? 

The best way to thin Rust-oleum is to start with 6 to 6.5 ounces of acetone for every gallon of Rust-oleum paint. In any case, factors such as humidity and the ambient temperature will typically influence how much you need to thin the paint.

Therefore, there’s always a bit of trial and error involved in thinning Rust-oleum. This explains why you must have a test piece such as a piece of scrap wood or metal resembling your project. 

The test material allows you to get a sneak peek of how your final project will look and shows if you need to adjust the ratios further. 

Rustoleum acetone ratio

Thinning Rust-oleum with acetone requires about 6.5 ounces of acetone for every gallon of Rust-oleum paint. This ratio should result in the best viscosity for spraying the paint but may require adjustment depending on conditions such as temperature and humidity. 

Rustoleum mineral spirits ratio

Thinning Rust-oleum with mineral spirits, like any thinning agent, requires a little bit of trial and error. This is why you want to record the ratios if you are using a viscometer to duplicate them in the future if you have a similar project. 

Nonetheless, about 6 grams of mineral spirits should be sufficient for every gallon of Rust-oleum.  

Is Thinning Rustoleum for Spray Painting always Necessary?

Yes, thinning the paint is necessary because Rust-oleum is generally low-viscosity and won’t flow well out of a spray gun without thinning. 

Suppose you intend to apply the paint using an airless sprayer. In that case, your Rust-oleum will require thinning with acetone or alcohol to achieve a higher viscosity consistent with the flow of the spray gun nozzle. However, you may not have to thin the paint if you use a high-power airless spraying system—but this is rare.

Canned paint’s thickness (viscosity) works well for brushing, but if you plan to spray it, you’ll likely have to thin it. The Rust-oleum paint manufacturer recommends using acetone for thinning their oil-based paint, with mineral spirits being better for cleanup.

Benefits of Thinning Paint when Using Spray Guns

The Rustoleum comes in spray paint cans that are well suited to small projects or medium-size surfaces. However, the manufacturer also packages the paints in large paint cans suitable for larger projects. 

You could use a paintbrush or roller to apply the paint from the can, but that is generally slower.   

These canned options require thinning with acetone or mineral spirits before using them in a spray gun to speed up the application process.  Thinning the paint before using it with the spray gun has these benefits: 

  • First, it significantly reduces the paint’s drying time on the surface. 
  • It ensures more consistent paint coverage and a smoother, more even sheen. 
  • Third, thinning the paint helps keep it from blocking and jamming the spraying mechanism. 
  • It also ensures better viscosity which leads to easier flowing and quicker application. 


Can I use xylene to thin oil-based paint?

Thinning Rust-oleum with xylene applies to specified oil-based paint varieties, varnish, lacquer, adhesives, epoxy, anti-rust, synthetic enamels, and porch & deck paints. Xylene also removes certain adhesives and is an excellent cleaning solvent for tools and equipment immediately after use.

Can you spray Rustoleum paint?

Yes, Rust-Oleum sells its rust-preventative product in spray cans suitable for smaller surfaces. However, if you are painting a large surface, you can purchase Rustoleum paint in a regular can and thin it for use with your spray gun. The latter is a cheaper option for such large projects. 

How to mix Rustoleum paint for spray gun

The correct way to mix gloss black Rustoleum for a spray gun is with acetone, xylene, or mineral spirits in a large container. Consider mixing one gallon of Rustoleum paint with 6.5 ounces of acetone or the other two thinning agents to get the desired paint consistency for your spray gun.

What type of paint is Rustoleum

It’s an oil-based enamel paint currently ranking as the best product for rust-proofing metal surfaces, including metal roofing sheets, cars, ships, and more.  

How do you spray oil-based Rust-Oleum?

To spray oil-based Rustoleum paint, start by thinning it with acetone in a bucket. After that, transfer the thinned paint into the tank of your spray gun and then spray it using the gun. 

How to thin Rustoleum oil-based paint

You can thin Rustoleum oil-based paints by mixing them with acetone, xylene, or mineral spirits in a container and stirring with a dowel or stirring stick. You should never use a lacquer thinner to thin paint of this nature.

What is the best paint sprayer for furniture projects?

The best paint sprayer for furniture projects would depend on the type of furniture you are painting. For instance, if you’re painting small pieces of furniture, go for the handheld HVLP paint sprayer from HomeRight or Wagner Spraytech. For larger furniture, you need HVLP paint sprayers with turbines like the Fuji Semi-Pro or an airless paint spray gun like the Graco 360 VSP.

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Thinning Rustoleum Paint for Spraying Summary

Thinning Rust-oleum paint is a straightforward process if you know the materials to use and the procedure to follow. All you need is a big bucket that can accommodate enough paint to complete your project, a stirring stick or dowel, and the Rustoleum paint. 

Stir the paint thoroughly in its original container to incorporate the paste from its wall and break any clumps settled at the bottom of the container. 

Once the paint is uniform, transfer it into the bucket, add about 6.5 grams of acetone per gallon of the paint, and stir to mix. Once it is ready, test it with a viscometer or directly on a test sample of your project. That simple process should get you your thinned Rustoleum paint. 

Don’t forget to read our next piece on “is Rustoleum waterproof?” if you’re looking to use Rustoleum for outdoor projects. Thanks for visiting, and good luck with your project! Happy woodworking!

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