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How to Thin Oil-Based Paint for Spray Gun – In 7 Easy Steps

You have probably attempted to paint your car, home, or piece of furniture using a spray gun but received unsatisfactory outcomes. You have wondered what exactly you did not get right. Probably, you even argued that it could be that you just did not have the appropriate training or expertise.

Well, chances are that you used the wrong kind of paint. The ordinary oil-based paint is too thick and viscous to use for painting surfaces. This is because the oil-based paints dry too fast and harden in such a manner as to be difficult to get rid of.

You have to thin it to make it easier to spread and convenient to apply by the use of a brush. For this to happen, you have to employ the right tools for the job and make use of the best kinds of equipment.

How To Thin Oil-Based Paint For Spray Gun Properly

For a start, thinning is basically the process of making an oil-based paint less viscous or more fluid. It mostly entails the use of thinning substances such as lacquer thinner, turpentine, and mineral spirit to break the viscosity of the paints and make it easier to spread out.

In our conversations here below, we are going to discuss the items you require for the job as well as the step-by-step procedures you have to follow to make this process a reality.

Tools and Materials Required

painting tools

You will first and foremost have to acquire the relevant tools-of-trade for the task. Below are some of the ‘must have’ items for this noble objective.

  • Apron
  • Overall
  • Face mask
  • Special containers
  • Bucket of warm water
  • Stick
  • Thinner e.g. mineral spirit, turpentine, or lacquer thinner

Step-by-step Procedures to Make Thinner

1. Put on the Right Protective Attire

Step by step guide how to mix paint for spray gun

Commence the entire process by putting on the right protective gear. Oil-based paints are generally harmful. They exude some strong stench which may cause cancer when inhaled repeatedly for a prolonged duration of time. This is why you have to put on some gas mask.

Because the paint hardens on the skin and clothes, you want to shield these two portions of your body from them. To do so, you have to put on a pair of gloves and overall. The former will shield your hands from direct contact with the paints whereas the latter will safeguard your clothes from the same dangers.

2. Pour the Paint in the Container

Next, proceed to pour the paint into the container. Before tackling this procedure, estimate the quantity of paint you might need for the given task. Choose a container that is large enough to accommodate that much paint.

Pour out the paint slowly and meticulously into the container. Take note of the calibrations to see to it that you do not exceed the expectations.

3. Add the Thinner


Now add the thinner of choice to the paint you have already poured into the container above. The ratio largely depends on the recommendations of the manufacturer. For this reason, you have to read through the manufacturer’s manual to determine this figure.

Generally speaking though, a ratio of 1:3 is the one that forms the standard for mixing these substances. This entails mixing one part of the thinner to three parts of the paint. Yet again, you are advised to be slow and meticulous in this process. You do not want to cause unnecessary havoc or spill some thinners to the ground.

4. Stir Thoroughly

Immediately after pouring the thinner into the paint, mix the two thoroughly using a special kind of stick. Start slowly and increase the pace consistently as the paint becomes thinner. The logic here is that you want to take great care not to spill any of the paint on the floor or the ground.

5. Test the Outcomes


Test the thinning outcomes after stirring the paint. This is to determine whether the outcomes are in line with your expectations. You may have to add more of the thinner if the resultant solution is too viscous. The opposite is applicable if the paint is too thin. Add more of the paint slowly, one at a time, and stir gently with time.

6. Place in Warm Water

Lastly, place the thinned paint in a bucket of warm water. This is to maintain the viscosity in the desired form and prevent the paint from hardening. Seal the container to prevent any loss of moisture. Be sure to use the paint within the shortest realistic duration of time after thinning. You may have to redo the entire process from scratch if you hold on for too long.

7. Pour in the Spray Gun

When you are ready to use the paint, you have to pour it into the spray gun. Open the canister of the spray gun and then channel the paint slowly into it. Take great care not to gill the canister with paint as this might impede its closing when the time comes to use it. You are now good to go!

Frequently Asked Questions

How do you thin oil-based paint?

In order for you to thin an oil-based paint, you need to use a petroleum-based product for thinning. With latex paint, you thin using water but with oil-based paints, you would need to use a commercialized paint thinner or mineral spirits to thin the paint.

For every three parts of paint, you add one part mineral spirits. So for three cups of paint, you use one cup of mineral spirits, or three quarts of paint would require an addition of one quart of mineral spirits. Stir the thinned paint completely and try a little out in your paint sprayer. If the paint is still too thick add a little more mineral spirits but remember to add the spirits in small increments, then stir and try the new solution before adding additional thinning material.

What is the ratio of paint to thinner for a spray gun?

The most frequently used ratio is three to one. That is three parts paint to one part thinning agent. This ratio changes according to the gun you are using, the tip you are using, the humidity and ambient temperature, and the paint you are using.

You should always read the paint gun manufacture recommendation on the thinning ratio and start with that amount. When you add additional amounts of thinner make each addition small and keep a record so the next time you use the same type of paint you have a reference to go by.

How do you thin oil-based paint for an HVLP spray gun?

The quickest method of thinning oil-based paint for the purpose of using in a high-pressure low volume spray paint gun is to measure one and one-half cups of paint out of the one-gallon paint container and then add one and one-half cups of mineral spirits or turpentine to the paint container. Stir the paint thoroughly and apply a small amount of paint to check for consistency before you fill the entire holding unit of the spray paint gun

How much thinner do I add to oil-based paint?

The most common recipe for thinning oil-based paint with petroleum-based products like paint thinner or mineral spirits is a three to one or four to one ratio. Begin with a four to one ratio and if that does not give you the desired thickness then graduate to the three to one ratio. Some paints are so thick that even the three parts to one part ratio will not be thin enough and at that point, you have to make measured paint and thinner substitutions until you get the consistency and flow from your tip that you prefer.

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Thinning is a task that is so simple that anyone can really do. You only have to be meticulous to prevent any dangers or damages from arising in the process. As such, you do not need to bring in an expert to help you out in this. You only need to adhere to the procedures stipulated above and also take your precious time to do the job.

The kind of information we have furnished is so precious that you cannot gain from it alone. You have to spread it as far as wide as possible. Be sure to let your friends and compatriots know about it. Best of luck also in your next thinning undertaking!

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