Air Compressor

I literally burnt through my 22 gallon, 1.3 hp direct drive Kobalt (Lowes) compressor a few months ago. Some of the things I used with it made the pump run constantly hence it was probably abused way beyond its design limits. I was using an air chisel to take up some flagstones on my front walk this Fall and after a few hours, smoke started curling from the motor and it died. I wasn’t too broke up about this. Other than the fact that it was undersized for my needs, it had the annoying habit of tripping the 15 amp breaker. As it turns out, this was bound to happen based on this chart. 1.3 hp on 120v would pull over 10 amps and start-up would occasionally exceed the breaker limit.

I've been shopping for a compressor ever since. I needed to determine the largest compressor I could put in my garage. Space wasn't necessarily a limiting factor but electricity certainly was. I originally ran a two-line 10 ga line to the garage from my residential electrical service. My guru, an electrical contractor for longer than I've been alive, told me to keep the required amperage for the garage under 30 amps. Looking at this chart, he was spot on. My frugal decision to run that meager line eliminated 5 hp compressors as they pull in the neighborhood of 30 amps under load. Also, most 5 hp compressors live in the $800-+$1000 range so I was happy to cross them off the list to avoid a spousal unit negative feedback loop. In hindsight, I should have run a much larger cable to the garage. Anyways, I set my sights on 2-3 hp. Most all pumps in this range are 220v.

I was looking for the best deal for a oil bath pump with a 2-3 hp motor, largest tank available. With this range averaging +10 cfm at 90 psi, it would drive most all air tools with the exception of very high volume attachments. Some attachments like jitterbug/rotational sanders, sand blasters and needle scalers (most excellent rust removing gizmos) could be used but not constantly.

Note on 220v: Most households have mainly 110v lines throughout the house. They also have a few 220v circuits to run laundry dryers, stoves and HVAC. The electrical box in the house has two “phases”, each at 110v. A circuit breaker connected to one phase is 110v. One of those double wide breakers connects to both phases providing 220v. In my case, I have my two-line service feed to the garage on two 110v breakers each on a separate phase. I had done this on purpose so I would have the option of using 220v in the garage should I need it. This reminds me, I need to change the two separate breakers in my house breaker box to separate but linked breakers so if one blows, they both shut down to kill the 220v line. This will deenergize the whole garage but nothing in there requires constant power like a fridge. Anyways, the box in my garage has 4 circuits breakers divided equally on the two phases. To add 220v to my garage, all I need to do is add a double wide breaker to pick up both phases with a goal to keep consumption under 30 amps and any given time.

I had scoped out my local Menards, Rural King (local farm supplies), a local Harbor Freight wannabe called Matrix and, of course, Harbor Freight. They all had 220v, 2-3 hp, 60 gallon, +10 cfm @ 90 psi compressors ranging from $450 to $850. I sat on the fence from the middle of the summer until last weekend. I hadn’t pull the trigger: enter Rural King and the Christmas season. Their Porter Cable 135 PSI 60 Gallon Vertical Air Compressor with the specs above was marked down about $75. I was quite happy with that but then my wife pointed to a flyer indicating the store was having a “tax free” sale that weekend saving another $30. So, my replacement compressor is now in my garage.

My next concern: air line plumbing, regulators, filters, oilers, and driers. Tools need regulators and oilers but not the driers. Spray guns need a regulator, filter and drier. So, I’ll probably put a drier and filter on the main line, then two regulators, one for a clean line and one for an oiled line. From there, I’ll probably run 3/8th rubber lines that will reach anywhere in the garage and maybe a quick coupler that will run through the wall for use outside.