It doesn’t matter if you need to pump up the basketball, car tire, or pressure wash the deck. An air compressor’s comes in handy. Whether you have a small five-gallon air compressor or a large industrial compressor, there are specific steps you need to take to make sure your tank doesn’t rust from the inside out.
Five expert tips to prevent rust in an air compressor tank.
Every time you use your air compressor, condensation will collect in the bottom of the tank. Here are five steps you can take to care for that resulting condensation:
- Drain, drain, drain it.
- Leave the drain open between uses.
- Use a purge valve/automatic tank drain and aftercooler.
- Use a water trap and filter regulator.
- Use an air dryer.
In this article, we’ll go deeper into each of these suggestions, when to use them, and discuss why water collects in the bottom of your air compressor.
Drain Your Air Compressor After Each Use
There are a couple of reasons you want to do this:
There’s the obvious one. It helps prevent rust from developing inside your compressor tank.
The less apparent reason is that it allows you to ensure that your compressor’s gauges correctly measure the total capacity of your tank. I recently was helping My brother with addition to his house, I set his house compressor up with an automatic drain system years ago, but we didn’t want to run a hose around the house. I grabbed a small portable compressor from his truck and totted it around back. Commenting on how much heavier it was than my newer one. After plugging it in, I glanced at the gauges and seen zero psi. I grabbed a 25-foot hose, plugged it in, and the compressor shut off, 2.5-gallon tank zero to 125 psi. in what had to be less than two minutes. That was quick, much faster than my newer compressor.
I jump up on the ladder with a nail gun in hand, running pressure blocks between the second-floor joist. One block in the compressor comes on shuts off. “That’s Fast,” I think to myself,
the second block, Six more Nails, Compressor clicks on, Something is Wrong.
Maybe the pressure switch is cycling too Quick? Jump down and head over to the compressor. The gauge reads 125 psi. I unplug the Airhose pull the pressure relief switch. Ten to fifteen seconds later, The compressor kicks on. The pressure switch was working correctly. The gauge reads 85, Explaining why the compressor was so heavy.
When you drain your compressor’s tank entirely, you essentially take it back to its factory settings. Meaning your pressure gauge will give you an accurate reading and won’t be rendered ineffective or inefficient because of water sitting in the bottom of your tank.
I quickly called my brother over, gave him, The your a dumb ass look, That only brother can truly appreciate as I opened the drain valve, letting him watch about 2 gallons of brown water shoot out on his plastic-covered sub-floor.
4 Easy Steps You Can Take to Drain Your Air Compressor Tank
The nice thing about this is. It is easy.
Put on your safety glasses. This way, if there is any debris in your tank, you won’t need to worry about it getting in your eyes.
Make sure your air compressor’s power is unplugged and/or turned off.
Pull the ring on the tank’s safety valve to reduce the tank’s air pressure to a level below 10 PSI (pounds per square inch). I find Using a rag to deflect the air and debris from blowing directly on me is much cleaner and safer.
Open the drain valve, located at the bottom of the tank. If you are draining a portable compressor, the drain valve may be located a little way up from the bottom. Tilt the tank positioning the valve to be located at the lowest point, allowing the water to completely drain from the tank.
Leave the Drain Open Between Each Use
There are many pros and cons to this one.
Some people prefer to leave the drain open the entire time between each use, so they know the water has completely drained out of the tank.
Others, though, prefer to close the drain once they’re sure the tank is dry. They prefer this because they’re concerned that leaving the drain open allows dirt, debris, and creepy crawly things to enter the tank. This could result in damage to any of your air tools.
Either way, you go. You definitely want to make sure that the drain is closed before you use your air compressor the next time.
I highly recommend adding a purge valve to all stationary air systems.
Use a Purge Valve/Automatic Tank Drain and Aftercooler
This is a tool that is placed at the drain valve location and is often used as part of larger, commercial air compressors, But due to competitive pricing, decreases have been economically feasible to install at home.
The purpose of this tool is to purge the water from the system by utilizing a timer, Every time the compressor is activated. This makes manual tank draining unnecessary since the tank is automatically drained for a few seconds. Every time the pressure switch closes to activate the compressor motor.
Another beneficial addition for large commercial air compressors is an aftercooler.
An aftercooler will significantly reduce the amount of water vapor that can enter your compressor, to begin with. It can do this because it traps the warm air, cools it, and then allows the air into the compressor tank.
Air Cooled Aftercooler 10 HP – Retails* for $219.
*Note: Price is as of the date of the writing of this article and may not be representative of current prices.
How much water you get depends on the relative humidity where you live.
Even on a “low humidity day,” Louisiana is going to experience much more condensation than Arizona would.
When the moisture-laden air is compressed in your air compressor, the hydrogen molecules condense from a vapor to a liquid resulting in the phenomenon we know as condensation. Now, instead of only having air in your compressor, you also have water.
Granted, it’s a small amount of water but left to its own devices, and it will result in rusting the inside of your compressor. This can lead to dangerous outcomes up to and including your compressor exploding when its structural integrity is no longer intact.
To know whether or not there is rust inside your compressor tank, check to see if any rust-colored water comes out when you drain your compressor.
Should I Have My Air Compressor’s tank Cleaned?
You may be wondering if you should have someone clean the inside of your air compressor or try to clean it yourself in case there’s rust in there. There are some who are willing to risk cleaning the inside of an air compressor tank, but it’s not recommended. Almost any process used to remove rust from the inside of your compressor tank will cause additional corrosion beyond whatever damage already exists.
If there’s rust inside of your air compressor’s tank, chances are the structural integrity has already been compromised to some degree, But short of x-raying the tank, there is no way to physically see what is going on structurally. I have looked inside many tanks with a borescope and have never seen a crack or pinhole. Upon inspection, I have found pinholes in the bottom of the tank and along welds. If that’s the case, it’s best to replace the tank. Do not weld a compressor tank!