Air compressors are widely used for many things. From inflating tires to nailing and drilling, you can do many things quickly and easily using an air compressor - including painting!
People use air compressors for painting because they are swift, efficient, and give a consistent flow. That means you can paint something within minutes and give it full, consistent coverage, even in places where it is difficult for other tools or equipment to reach.
Moreover, you can use the air compressor to paint cars, furniture, walls, and many others. No matter what kind or size paint job you have, the air compressor can help you finish it successfully. Let's explore this topic more and see what else you need to know about spray painting using air compressors.
Calculating the Required Air Compressor Size for Painting
If you need to do some spray painting with an air compressor, you need to consider a few things. When buying the compressor, you must consider your desired CFM, PSI, HP, tank size, etc. Let's look at the best way to calculate the perfect air compressor size before you go out and buy one:
How to calculate the CFM requirements for your painting tool
If you look at any given air compressor, you should be able to find a specific CFM written somewhere on it. The same goes for your painting tools. You will get a CFM rating depending on your particular tool. Often, it takes more than matching the CFM of the compressor and the tool to work well together.
To select a good CFM for your air compressor, you need to think about the number of tools you will use with it and how those tools work. That means you should first select the tool and then select a compressor.
To calculate the CFM required for your painting tool, you need to think about whether you will be using the tool continuously or with breaks. If you go with the former, you should calculate the compressor's CFM with a longer duty cycle in mind. If you use the tool with breaks, you can calculate the compressor's CFM with a shorter duty cycle in mind.
This can be very confusing, so finding tools that already have a given CFM number is better. You will not need to calculate anything on your own. Better yet, you can use CFM calculators online for this purpose.
Example calculations for common painting tools
An example painting tool would be a spray paint gun. You can use either an LVLP or HVLP spray gun when doing anything from small painting jobs to total auto painting.
To calculate the CFM for your painting tool, you need to consider the area you need to cover, the height, and the ACH or air change per hour. You multiply the three numbers and then divide them by 60 to get an accurate CFM. But this works best when calculating CFM for a given area or room, not so much for cars and similar things.
Again, instead of calculating the CFM of your tool, you can always find it written on the tool or its packaging. If there is no mention of it, you can talk to the manufacturer to find out the exact CFM of the tool's make and model.
Understanding how the CFM requirements change when using multiple tools
If you need to use several tools at the same time and on the same air compressor, you need to be mindful of the total CFM. You would take the separate CFM of all air tools and add them until you get one number.
Let's say you have a paint gun that requires 60 CFM. Then, you have a drill that requires 40 CFM. The air compressor's CFM would have to be at least 100 CFM to power both tools. One powerful air compressor will complete the job faster and easier than a smaller compressor, suitable for one tool at a time.
Factors to Consider When Choosing an Air Compressor for Painting
Quite a few things go into choosing the perfect air compressor for spray painting. As mentioned before, you need to think of the CFM, the PSI, the HP, and the paint sprayer tank. Let's look into the factors more closely, see what they mean, and how you can determine their value easily:
CFM and PSI: Explanation of what these terms mean and why they are important
CFM and PSI are two very important measurements. When you look into compressors, these are the two things that you will need to determine from the get-go.
CFM is short for cubic feet per minute. This measurement tells you how much air your compressor produces at a specific pressure. The CFM of an air compressor can go from less than one to forty.
PSI is short for pounds per square inch. This measurement tells you how much pressure an air compressor has. The pressure rating varies between compressors and tools, but when it comes to painting, it will be around 90.
Knowing the CFM and PSI of your air compressor is essential because it can help you determine whether the compressed air it produces is enough to power your spray gun. It can also help you choose the paint sprayers you can pair it with. So, you have to know the exact value of these measurements before starting your paint job.
Painting Tool Requirements: What CFM and PSI rating does the painting tool require?
Each paint tool comes with specific CFM and PSI ratings. The rating of the CFM and PSI can change between tools, models, and uses. For example, these ratings would be higher if you need to paint a car than if you need to paint furniture.
If you look at a tool's specifications, you will find its CFM and PSI. For pneumatic tools, for which you can use an air compressor, the PSI will be about 90. But the CFM varies and is usually within these values:
- Grinding air tools require an air compressor with a 5 to 8 CFM rating
- Nailing air tools require an air compressor with a 0.3 CFM rating
- Sawing air tools require an air compressor with a 5 CFM rating
- Painting air tools require an air compressor with a 3 to 12 CFM rating
Some air spray guns may have a higher CFM requirement than others. It comes down to the one you want and the intended use.
Tank Size: How does the tank size of the air compressor affect painting?
When painting something, you must have a tool with a big enough tank to ensure continuous airflow through the project. Imagine painting cars and having your paint run out in the middle of the project. It will take a while to put in new paint and start working.
Changing color in the middle of the project might not result in an even coat at the end. Especially when you work on painting cars, you will need a clear coat with no bubbles or dots. If you stop periodically, you will surely have at least some bubbles in the coat.
The same goes for painting furniture - you need the compressor to give you continuous air and the tool's tank to give you enough paint. Depending on the size of your project, you can decide on the tank volume. Here are some tank volumes you might come across:
- To paint a house, you need a 60 to an 80-gallon air compressor
- To paint a car, you need a 20 to a 40-gallon air compressor
- To paint furniture, you need a 40 to a 60-gallon air compressor
- To paint about 150 square feet, you need a 10-gallon air compressor.
As you can see, the tank volume can vary between the paint jobs you have. That is something you have to keep in mind before you start the project.
Horsepower: How does horsepower impact the performance of the air compressor?
Horsepower is important when you have a painting project, but it is not the most important thing. It helps you determine the amount of work the compressor's motor can give you. The higher the HP, the more power your compressor will provide.
The best air compressor will have about 5 or 6 HP. A small compressor can have about 3 HP and still be suitable for a decent spray painting project.
Thank you for reading this guide on the best air compressor size for spray painting. Remember to look into the CFM and PSI of the compressor and the spray gun, ensuring that the CFM of the compressor is higher than the CFM of the tool used to spray paint.
If you use only one tool, consider it CFM only. If you are using several tools, you must add the CFM ratings of each to determine the CFM needed from the air compressor.
Finally, if you have had any experience with painting with compressors, let me know in the comments below. I appreciate your input on the topic.