The majority of people who have used a paint sprayer have come upon the problem of needing to thin the substance they are using and being uncertain exactly how much thinning was required. The manufacturer usually gives a recommendation with the equipment, but most people do not keep that paperwork and by the time their next project using that substance rolls around they have forgotten the mixing formula.
We talked to several professionals who use paint-spraying equipment on a regular basis to help us tell our readers how to thin paint for a spray gun. We must say that you should always follow the recommendations of the manufacturer of the equipment you are using. The following recommendations are generalized guidelines and are not specific to any piece of equipment.
Using A Viscosity Cup
Most paint sprayers come with a viscosity cup, and this device will help you decide if the paint is the right consistency without pouring it into the container cup, spraying, and then pouring it out to make adjustments.
The viscosity cup is like a funnel. You pour the paint into the large open section of the cup and see if it can flow smoothly and consistently through the narrow opening. If it can the paint is good to go and if it cannot then you need to do some thinning.
How to Thin Paint for Different Sprayers
HVLP and airless paint guns may require different thinning ratios.
Airless Paint Sprayers
The airless equipment is often capable of spraying thicker substances than the air-powered or HVLP sprayers. Often an airless sprayer will not require any thinning of latex paint and will allow you to spray the paint directly from the manufacturer’s container.
The sprayers that can handle un-thinned paints are usually the bigger and more expensive units. The smaller units purchased by most homeowners usually work much better if the paint is thinned prior to use.
You will typically use less than 20% water to create the right consistency for your equipment. Thin by adding small amounts at a time until you discover your exact ratio needs.
Paint Thinning for HVLP Sprayers
These sprayers are designed to perform best when you are using oil-based paint. That does not mean you cannot use latex; it simply means you have to discover the perfect paint-to-water ratio that will give you the consistency that you want.
Always start with thinning about 10%. It is much easier to add water than it is to remove water or wait for the paint to thicken.
Latex Paints Thinning Steps
One of the paint substances that usually need to be thinned before it can be sprayed is latex paint. This substance is a common choice by homeowners because it dries faster than oil-based substances, and it is good for general projects around the home.
Latex is a water-based substance that is similar to acrylic because the formula includes an acrylic resin. It is normally available in large containers like 1-gallon and 5-gallon buckets because of its popularity as an interior ceiling and wall paint.
Latex paint may need to be thinned by as much as 10% before it can be sprayed through a sprayer. That ratio works out to be ¼ cup of water to 1 gallon of paint. If you are working with an HVLP sprayer the ratio may need to be increased to thin the paint by as much as 20 or 30%.
Latex paint is:
- Usually cheaper than acrylic
- Can be cleaned up using soap and water
- Is non-toxic
- Is thick so it usually takes fewer coats to complete coverage
- Has fewer fumes than acrylic
- Dries faster than acrylic
How to Thin Latex Paint for a Spray Gun
This thinning will be accomplished with water because this is a water-based substance.
You will need:
- Latex paint
- Stirring sticks
- Water
- Measuring cup or container
- Empty bucket or container for the thinned paint
- Funnel
- Spray gun
Step by Step Latex Paint Thinning
Step 1. The paint in the container needs to be stirred so it is blended properly.
Step 2. Take the empty bucket and pour the amount of paint you want to thin into the bucket.
Step 3. You need to measure about ¼ cup of clean water. When you are thinning paint, you want to add the thinning agent in small increments so you do not pour too much in and get your paint too runny. NEVER add more than ¼ cup at a time and you will not have this problem.
Step 4. Pour the water into the bucket with the paint and stir it to make it a consistent thickness.
Step 5. Use the funnel to fill the paint container on your spray gun with the freshly thinned paint.
Step 6. Spray a test spray on cardboard. This test spray will tell you if the paint is the right consistency. If the paint is too thick and hard to spray you need to pour it back into the mixing bucket add a little more water, stir, and fill your paint container again. If the paint is too thin you can add more paint to the thinning bucket to thicken the substance, or you can wait a little while and let the paint begin to thicken up naturally.
Step 7. When you have the paint at the exact consistency that you like write down the ratio of water to paint that you used. Keep this information with the paint gun and you will not have to go through the process of trial and error again.
Oil-Based Paints Thinning for Sprayer
These paints create beautiful finishes that last longer than the finish from most other paint substances. They often need to be thinned because they are too thick to flow properly from your spray-painting equipment.
Oil-based paints require something other than water to be used to thin them. They need thinning agents that are petroleum-based. You can use things like lacquer thinner, turpentine, or mineral spirits to create the proper paint consistency you need.
How to Thin Oil-Based Paint for Spray Gun
Gather the supplies you need first.
- An apron or clothing protection because oil-based paints and thinners do not wash out of clothing.
- Bucket of warm water
- Empty bucket or container for the paint mixture
- Measuring cup for thinner
- Stirring sticks
- Paint
- Your thinner of choice
The basic thinning ratio for oil-based paints is no different than latex paints. ¼ cup of thinning agent mixed with one gallon of paint will thin the substance by 10% which for most applications is a perfect consistency.
Step 1: Cover your clothing and protect your eyes, hair, and such from possible paint exposure.
Step 2: Get your empty bucket out and pour the paint you want to thin into it.
Step 3. Get your empty bucket out and pour the paint you want to thin into it. Measure a small amount of paint, about ¼ cup, and slowly add it to the paint in the bucket. You need to add a portion of the thinning agent and stir to mix the paint together, then add some more thinning agent if the mixture is not the right consistency. Do not simply pour all of the thinners into the paint without going through the increment steps. If the paint is too thin you cannot remove some of the thinner. If the paint is still too thick you can always add a little more. It is like the toothpaste you cannot put it back into the tube after you have squeezed it out.
Step 4: Use a viscosity cup to determine if the thickness is right. If you do not have a viscosity cup then fill the container of your paint sprayer and do a test spray to determine if the thickness is going to work or not.
Expert Tips for Paint Thinning
- Create a small notebook where you write down the amount of paint and thinner you use for each paint variety you use. This notebook will save you time and money in the future when you use the same thickness of paint again. Be sure that you write down the brand of paint and not just the type of paint because different paint brands can be different thicknesses.
- Always measure very small amounts of thinner at a time, no more than ¼ cup for each gallon. You will have to stir more and may have to add more but it is better than over-thinning your paint.
- Always make sure you have adequate ventilation when you are mixing paints, even when you are mixing water-based paints.
Frequently Asked Questions
What is the ratio of paint to thinner for a spray gun?
The most frequently used ratio is ¼ cup of thinner for each one-gallon of paint. That is thinning the paint by about 10%.
Do you dilute paint when using a sprayer?
You should check the viscosity of the paint and if it is too thick to flow properly from the viscosity cup then you do need to dilute or thin the paint. Latex paints normally always have to be thinned for most homeowner equipment.
Do I need to thin paint for the Wagner sprayer?
A Wagner sprayer is no different from most sprayers in the paint thickness categories. Thinning requirements will be based on the sprayer you are using and the paint you are using. Most latex, chalk, and milk paints will need to be thinned prior to use.
Read More>> Chalk Paint vs Regular Latex Paint
Final Word
Using a paint sprayer often requires you to thin the paint down a tad. Learning how to do this, and learning what the perfect consistency of paint actually looks like will allow you to thin future paints faster and without all of the testing and additional mixing.
If you can keep your paint to a thinner ratio written down you will thank yourself when you paint the same area again later. Also, write down the exact color of paint and brand that you use in a room. If you want to touch up or repeat the same color you will have the information you need to help you buy more.
