If you are a home or hobbyist mechanic you have probably worked your way up through a few different compressors and as you pay more you get more.. Higher horsepower compressors with larger tanks are always something that every mechanic wants but spending the money to jump from different levels of compressors can seem less cost effective then trying to supplement your current compressor with a larger tank.

Well thats the idea that goes through most of our minds when we are considering upgrading. If our current compressor works well then wouldn’t a larger tank reduce the downtime between re-pressurization?

Often this idea comes to mind when we are at the point of going from 110V power to 220v and we are trying to delay the cost of calling an electrician. Unfortunately things just don’t seem to work out in the end for the average shop if you decide to try this.

First what is the problem that you are trying to solve? You want to extend the time that you can paint or use a tool before your compressor kicks on.

Well a Larger tank with the same horsepower compressor can achieve this but only if you are willing to wait longer for re-pressurization. What you end up doing is doubling your tank size and extending your working time a couple minutes but then when the compressor kicks in you have to wait and wait and wait. A smaller or “Matched” sized tank will give you a good offset between work time and down time. You end up having more cycles but you are back to work faster and that can matter if you are painting.

When is adding a tank to your compressor a good idea?

Well one instance I found was when I purchased an Air Brush Compressor that was Tankless. The Compressor could run constantly however over an extended time the motor would get hot and that meant I ended up burning out my first motor in about 3 months. When I purchased my second small compressor dedicated to Airbrushing I had a choice I could go with a 5hp compressor with a large tank that I would probably cycle 2 – 3 times during a job that would be totally overkill and too large to take with me or i could go with a air brush compressor and add a tank of my own. What I did was get an old freon tank from a buddy and retrofitted it with an off the shelf adapter for filling tires and then i spit that and ran one line to the compressor and one to my brush.

In addition to giving me some extra work time it also removed some of the pulse that a tankless compressor has.

Well you’re probably saying thats an air brush it uses probably .5cfm @ 20psi it can last all day.. and you’re right it can last a while but the example is the same for any compressor.

If you had your shop running on a small compressor with large tanks thats going to mean you better leave them on over night to fill up for the next day.. well not that extreme but can you imagine the whole shop coming to a standstill because its going to take 30 minutes or an hour to refill your extra tanks?

Not to mention if you run your compressor for an extended time … longer than the amount it was rated to run to fill a smaller tank then its going to get hot.. and you’re going to burn out your motor much faster.

So, whats the solution?

Buy a Larger Compressor with a larger Tank thats matched to it. There is no real work around…

If you are at that point and you need to upgrade from say a 7cfm to a 9 or 12cfm compressor and you know that means a call to an electrician then you might also think about upgrading another outlet that will let you run a plasma cutter or larger mig welder. just be thankful you don’t have to instal three phase in your home or the cost will be through the roof.

On the other hand if you only do a few projects a year or maybe one project every other year.. then live with your maximum availability and just take a little extra time to get things done.