How to Thin Oil Based Paint for a Spray Gun

What is Oil Based Paint?

Oil based paint are available in two different types.  Alkyd, which is synthetic or linseed, a natural oil.  Alkyd paint is less expensive and tougher, so it is more common.  

Oil based paints are more durable making them the best for exterior work, doors, bathrooms, kitchen cabinets or trim.  Oil paints take longer to dry and clean up requires paint thinner/turpentine/mineral spirits. 

Is Acrylic Paint Oil Based?

No.  Acrylic paint is water based.  You may find paint labelled either latex OR acrylic.  They are the same thing and you use them in the same way.  Thin and clean with water.

How is Oil Paint Different than Latex Paint?

Unlike latex, which is water based, oil based paints are based on a formula of mineral spirits and petrochemical solvents.  This makes them less popular than latex.  

If you need durability against high use and exterior weather, oil based is the clear winner.

Oil Paint	Latex Paint
Oil based	Water based
Richer Color	Good for Walls/Ceilings
More Durable	Budget Friendly
Stands up to low/high heat	Dries fast
Covers stains: no bleed through	Easy Clean up
Dries slowly	Not as durable
Longer Clean up	Stains may bleed through

How to Use Oil Paints: Painting with Oil Based Paint

There are just some things that only oil based paints can do such as:

• Protect against outside weather, low/high temps with oil based house paint 
• Guards against mold and mildew in high humidity areas such as bathrooms and kitchens with specialty oil based paints
• Blocks stains and keeps them from bleeding through the new paint with oil based wall and interior paint

Painting with oil based paints means dealing with a bit more fumes during and after painting called VOC’s.  Although these days they even make oil paint with low VOCs. 

Drying time is also longer, but we think it’s a trade off for richer more durable colors and better paint coverage.

Clean up is the more difficult part.  You have to use mineral spirits or turpentine to clean your paint sprayer and brushes instead of just water.

Should Oil Based Paint or Primer Be Thinned So It Can Be Sprayed? 

Whether or not a primer can be thinned so it can be applied with a paint sprayer depends on the paint manufacturer. Even the best home paint sprayers may not be able to spray oil based paint even if thinned.  Yes, it’s true that you have to thin oil based paint for most if not all HVLP (High Volume Low Pressure) DIY spray guns you find online.

How much to thin old based paint when using a sprayer should be found on the paint can.  Some oil based paints can’t be thinned so make sure to read the can before you get started.

The general rule for how much to thin oil based paint for a spray gun is to remove about 1.5 cups of primer from a 1-gallon can and then add 1.5 cups of thinning agent to the product.

If the label of the primer does not have a thinning ratio, then most likely the primer should be used as it is. Run the undiluted primer through your sprayer to evaluate its thickness. 

In most cases, it will spray as a thin mist and you’ll be fine.   If it sprays thickly, then you may need to apply the primer manually. 

Attempting to thin a primer that is not intended to be thinned can change how it applies, how it dries, or how it supports a layer of paint in the future. 

Thinning Oil Based Paint

Definitely do your research and make sure you purchase a paint that can be thinned for a spray gun.  Paints that can be thinned will list so on the paint can.

Some will even list the ratio of thinner to paint, making it easier and faster for you to get painting.  

What You’ll need to Thin Oil Based Paint for a Spray Gun: Supply List

• clean bucket
• paint strainers
• clean stir sticks or a Paint Mixer Drill Attachment
• funnel
• turpentine or mineral spirits

 

How to Thin Oil Based Paint for a Spray Gun

If you are trying to thin an oil based paint or primer, you can’t use water to do it. Water and oil don’t mix. You’ll need to use mineral spirits to get the job done.   The cost of thinning oil based paint for a sprayer is cheap: the cost of a large can of mineral spirits or paint thinner in your area so about $10-20.  And you’ll have some left over!

For oil based primer, follow the manufacturers instructions on how to thin.

Steps for Thinning Oil Based Paint for Your Sprayer

Pro Tip when Thinning Oil Based Paint for your Spray Gun

Thin Oil Based Paint Right the First Time

 If the paint is able to flow freely through the funnel, then you have the correct consistency. 

 Should the paint clog up in the funnel, then add another 1 part mineral spirits or turpentine to the paint in the container.

 Then thoroughly mix the product with another clean stir stick. 

 Continue this process, adding your mixing agent, as necessary until the paint flows freely through the funnel. 

If your oil based paint is still not thin enough for your spray gun, add small amounts of the thinning agent and test until you reach the right consistency for spraying. 

What Happens to Oil Based Paint when I add Mineral Spirits? 

Once mineral spirits or turpentine is added to oil based paint to thin them for a spray gun, the characteristics of the paint will change.

The color may be lighter or darker and the drying time may be different. 

Thinner paint typically requires more coats for complete coverage and a desired finished.  Factor this is along with extra drying time when completing your projects. 

Why Should I use an Oil Based Paint? 

For a long-term project, an oil-based primer is a better option. Oil-based primers take more time to dry and require thinning to apply through a spray gun.  The results tend to last much longer compared to other primer  and paint types. 

Some paint types are incompatible with some primer types. Be sure to follow the recommendations of the manufacturer when using any primer or paint. 

Oil based paint has many advantages over latex paint, and may be the best paint to use depending on your project.

Advantages of Using Oil Based Paints

1. Oil based paints are better is low temperature climates
2. More durable, best for trim and walls that see tons of use
3. Better coverage than latex, especially on imperfections and damaged areas
4. Great stain coverage, great for cupboards, high traffic areas
5. Richer or deeper colors than water based paints

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Painting with Oil Based Paint

Painting with oil based instead of water based paint requires a different approach.  With latex, you can just apply a new coat over top of the old coat of paint. 

Not with oil based paint.  You have to be careful to test the old paint coats type to make sure you don’t apply oil based paint over latex paint.

Oil Based Paint Over Latex Paint

If you apply oil based paint over latex, you could have problems down the road.  If moisture or changes in temperature affect the base coat of latex, the whole paint job could start bubbling and lift the oil paint right off. 

Painting latex over oil is OK but oil over latex is a no no. 

Pro Tip: Always use a primer!

Lifting, bubbling and chipping will happen and you will have to remove all of the paint and start from scratch.

According to Glidden, testing if the base coat is latex or oil is as simple as dipping a cotton ball in some alcohol and rubbing it over a small area.  If the cotton ball is clean, then you have oil based paint.

Can you use a Roller with Oil Based Paint?

The answer is yes.  You can you all of the same tools with oil based paint that you use with latex paint. 

However, you will want to purchase higher end products to apply your paint. 

This is because you will be cleaning them with mineral spirits or turpentine and you want the rollers, brushes and trays to be able to withstand the cleaning process. 

Safety and Working with Oil Based Paints and Primers 

Oil Based Paint Fumes

Many paints contain harmful vapors that can enter your lungs. Some vapors may cause asthma-like symptoms when they are inhaled. Once symptoms appear, they may take several weeks to begin improving. 

When painting with a paint sprayer, atomized molecules can enter your airway.  

If you don’t wear a respirator, those chemicals will enter your air passageways when you tackle your next painting project. 

The goal of a paint respirator or mask is to make sure you can still keep breathing easily.  Even if there are vapors, paint molecules, or chemical contaminants in your immediate vicinity.  

A paint mask guards against the nuisance contaminants that are in your environment. For example, dust, pollen, and other non-toxic particles. 

Paint respirators are required to provide protection against vapors and harmful chemicals. Some models may even protect against mold spores and other small contaminants. 

You mostly likely need a specific type of respirator, such as a vapor-resistant model, for specific results. 

When using a paint sprayer, a pair of painting coveralls with a hood is a good investment. You’ll protect your hair and clothes without worrying about what happens. 

DuPoint makes a Tyvek coverall suit that is extremely affordable and includes shoe protection as well that is available on Amazon.  

Oil Based Paint Drying Time

Oil based paint is more durable and thicker than latex which means it takes longer to dry.  Expect is to be dry to the touch in about 6-8 hours and ready for a second coat in 24 hours. 

Of course, if you live in a high humidity area, the drying time will take longer than if you live in a drier climate.

We go into a ton of detail about how long paint should dry between coats in our new post.

Cleaning Your Paint Sprayer after Using Oil Based Paint

The video will walk you through how to clean your sprayer after using oil based paints.  The cleaning kit in the video does a great job and is available here.

 How to Thin Oil Based Paint for a Spray Gun

Best Oil Based Paint: Editor’s Choice 

Rust-Oleum Oil Based Paint

If you live in a high moisture environment (we’re talking about you, Pacific Northwest!), then rust, mold and mildew are top priorities. 

This quick drying formula will be dry to the touch in 2-4 hours versus other brands that can take 6-8 hours.

This oil based paint is rust resistant so you don’t need to worry about your projects getting rusty.  Great for exterior and metal projects.   

This is a solid, versatile oil based paint option that can go anywhere and on almost anything from metal roofs to trailers and fridges, this paint is super versatile.  

Conclusion How to Thin Oil Based Paint for a Spray Gun

Oil based paints provide a ton of advantages over latex paint.  Depending of what you are painting and your desired finish, you may choose to use oil based paint over latex.

Thinning oil based paint for your sprayer is different than with latex paint. 

Our 5 step simple process on how to thin oil based paint for a spray gun will get you painting faster than you thought you could.

FAQs  How to Thin Oil Based Paint for a Spray Gun