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How To Thin Latex Paint for A Spray Gun – DIY Tips


Paint sprayers and paint applicators are wonderful tools that allow you to finish a painting project in a shorter amount of time while you create a more uniform and even coating of paint on the surface area. In order to successfully paint using a paint gun, you will usually have to thin your paint down before you begin to apply it.

The trick to getting a uniform coating of paint and a professional-looking finish is for you to thin the paint to precisely the correct thickness. If you get the paint too thin it will be watery and it will take several more layers of paint before it looks like you want it to look. If you get the paint too thick then you will have trouble getting the paint to go through the sprayer and you will waste time and effort trying to do the work.

Start with the Right Materials and Tools

To do any job properly you have to have the proper tools to do the job. You will need:

Some paint guns are highly developed and can actually pump the paint directly from the bucket the paint comes in. Most of these sprayers do not even require you to thin latex paint. If you have this type of paint sprayer the manufacturer’s instructions and user manual will detail how you should test your paint to make certain that it is the proper thickness for the paint sprayer you have.

For the majority of paint sprayers, you can determine if the paint will adequately go through the paint sprayer by pouring the paint into an ordinary household funnel with a small spout. If the paint can pass through the small spout of the household funnel then it will more than likely be able to be dispensed by the paint spray gun. If the paint has a hard time moving through the spout of the funnel then

How to Thin Latex Paint For a Spray Gun

First, go to an area where it does not matter if you have a spill while you are transferring the paint and mixing the paint.

  1. Open the paint container and make certain that it is stirred completely. If you did not just get the paint from the store where it was shaken by the paint mixing machine, then you stir that paint making sure that you get the paint in the bottom of the can to blend into the paint throughout the container.
  2. Pour the paint, or the amount of paint that you desire to mix, into a clean and empty bucket. You should not mix more paint than you can use at one time because as the paint sits it will thicken back up and you will have to thin it again. If you are mixing the paint each time you are loading the gun then you will learn exactly what ratio of paint to mix with what ratio of water and all of your paint will be of equal consistency.
  3. Add the water one-quarter of a cup at a time. This small amount of water will allow you to properly mix the paint without getting the paint too thin and having to add more paint and so on. You want to add small amounts of water each time, stir the water into the paint thoroughly, then test the paint to see if it is properly thinned.
  4. Test the paint to see if it is the right thickness for the application you need. You can hold a funnel with a thin spout over the paint mixture bucket and see if the paint flows evenly through the spout. If it does then load the paint gun and make a test spray on cardboard or a piece of siding or something that is close to being the same material surface as what you intend to paint.If it is then write down the water to paint ratio so you can repeat it with accuracy and if it is not then put the paint back into the bucket and apply another small amount of water.
  5. Repeat steps three and four until the paint is the precise consistency that you prefer.

How to Thin Latex Paint for Wagner Spray Gun

How to thin latex paint for Wagner spray gun

Wagner spray paint guns are capable of spraying latex paint but you are going to need to thin the paint to a consistency that creates a good thickness on the surface you are painting. You never want to put paint on so thickly that it runs and you never want the paint to be so thin that you can read a newspaper through it when it is applied.

Wagner spray paint guns suggest the following starting mixture for latex thinning.

  • Pour one-half of a gallon of cleanroom temperature water into a clean container that has a lid.
  • Pour the gallon of latex paint into the container with half of a gallon of water.
  • Place the lid on the container and shake the container in a back and forth and side to side motion for four to five minutes to mix the paint completely.
  • Open the container and check the consistency of the paint.
  • If the paint is not thinned to your preferences and your paint sprayer specifications then you need to add one-half of a cup of water and repeat the shaking process.
  • Check the paint after each shaking process to determine whether it has been thinned enough.

Also, check out the below video for more tips:

Few Pro Tips for Using Latex Paint

Paint Thinning

The thinning of your paint will be determined by the application you are using, whether you are painting on the interior of a home or the exterior of a home, and the material you will be painting. All of these factors will play a part in how thin you will want your paint to be. The thickness of the paint determines the number of coats of paint it takes to complete and adequate coverage.

Different Guns Take Different Blends

Each manufacturer’s gun and each different style of paint gun will require a different thickness of paint in order for it to dispense the paint perfectly. You have to learn your paint gun and the blends that work best in it.

Test Areas Save you

You want to have a test area. Like a piece of siding, or plywood that you can use to spray the paint on to determine if your paint mixture is thinned properly. Each time you thin the paint down you will spray a little on the test area to determine if it is at the proper proportions yet.

If your paint creates runs you have thinned it too much and if you are not getting an even coverage, or the painted area appears splotchy,  then you still need to thin the paint more.

Weather Interferes with Paint Thickness

Start by setting your airflow to the manufacturer’s recommended settings and thin the paint according to what the manufacturer recommends. This will be written on the side of your paint gun. Remember that the humidity and temperature of the air will affect the thickness of paint so when it is cool weather you will need to thin your paint to a different thickness than when it is hot weather.

Used Paint and the Paint Sprayer

If you are using used paint make certain that you stir the paint well, and then strain the paint before you try to use the paint in your spray paint gun. Used paint can often have tidbits of dirt and debris or pieces of paint that have thickened so you want to get these items strained out of the paint before you attempt to use the paint.

Frequently Asked Questions

Do you need thin latex paint for a sprayer?

Yes, you do need to thin latex paint. Latex paint is a water-based paint but it is almost always thicker than oil-based paints are. Latex is too thick to be distributed through the paint sprayer in a thin and even mist.

Before you paint using any paint application use the stir stick method to evaluate the thickness of your paint. If the paint substance adheres to the paint stick or falls from the paint stick in a blob then the paint is too thick to be applied properly. The thick

ness of the paint needs to be considered when you use a spray paint gun, a roller, or a brush.

Can you spray latex paint with an HVLP gun?

The ability to spray latex paint through an HVLP paint sprayer is going to depend on the spray paint gun, and the thickness of the paint you are applying. First and foremost you should always read the manufacturer’s recommendation of the paint sprayer you are using. If the manufacturer says that latex paints can be used then you proceed with properly thinning and preparing the paint before placing it in the equipment.

Can latex paint be thinned with water?

Latex base is a water formulated substance so you do use water when you are thinking it. Do not use mineral spirits or other popular thinners with latex paint because those thinners will break the paint down.

Your manufacture will have a manual of instructions included with the paint sprayer and the method of thinning the different paints will be addressed. Remember that you then paint by adding a very small amount of water at a time. You can always add more water but you cannot remove the water once it has been added.

Can you thin latex paint with mineral spirits?

Mineral spirits are a petroleum-based product and latex paint is a water-based product. You have heard the saying that oil and water do not mix. That saying is true of any petroleum-based product and latex paint combination. The two substances cannot be mixed or combined.

The mineral spirits will actually work against the latex paint and stop the paint from adhering, or worse. Always read the paint can label and if it says latex then you always use regular tap water to thin the paint down.


Final Word

You want to always start with the manufacturer’s recommended thickness settings and then make adjustments according to the material type, the weather conditions, and your personal preferences.

Using a spray gun makes painting easier, but it does take a little time and practice before you learn the techniques to apply the paint and create a professional-looking finish. Never paint when you are in a hurry, and never paint when the temperature of the air in the room is freezing or below freezing.

Make sure that you have adequate ventilation in a room where you are painting. This is for your health and it will also cause the paint to dry quicker.

About Lisa Bohrer

Lisa is a native Texan who says she wears many hats. She is a wife, mother, grandmother, farmer, animal lover, fisherwoman, gardener, and college student. Lisa is a sophomore at Liberty University where she is taking classes to earn her Associates Degree in Creative Writing. She and her husband of 35 years fill their days with life on the farm raising goats and chickens, and then most evenings she can be found at the computer writing, or researching a topic that has piqued her interest.

2 thoughts on “How To Thin Latex Paint for A Spray Gun – DIY Tips”

  1. in this article you start out with thinning latex paint with a picture of a can of naptha and a can of latex paint. some people dont like to read on because they are looking for a quick answer and see can of Naptha and a can of latex paint, oh! must be able to mix it. any way i mixed latex with a bunch of napta for a dog house. looked so bad we just lit it on fire, it burrned nicely!


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