Air compressor advice PSI & capacity

[milty60]

My wife is thinking of getting me an air compressor for Xmas (she works at Tractor Supply - think Porter & Cable is the brand) What PSI and Gallon capacity is a minimum requirement and/or well equipped? Will be mostly used for automotive work but possibly (other family members) spray painting , sand blasting , glass etching, etc .   Need to know soon - sale and employee discount ends tomorrow at 9 PM. 

 

Thanks, 

 

Milty 

[idosubaru]

Look at *volume* first, not necessarily tank size and PSI. 

 

Find the CFM of the tools you think you'd buy - and get a compressor rated a little more than the highest CFM you'll use.  Like look them up at Tractor Supply or wherever you'd buy your tools and see what CFM they use. 

 

Then buy all Milton high flow connectors for all your fittings.  They're cheap and well worth it - they greatly improve flow and performance. 

 

Just for example from TSC:

Sand blaster 5 CFM

https://www.tractorsupply.com/tsc/product/jobsmart-abrasive-blast-cabinet

 

Spray gun 8CFM:

https://www.tractorsupply.com/tsc/product/ingersoll-rand-hvlp-gravity-feed-spray-gun

Glass etching - I don't know what that is.

 

So you'd size for the 8 CFM spray gun and want like 10 for some margin.  And even more if you think you'll upgrade tool capabilities in the future. If you ask for a compressor this year are you going to want more tools for birthday/christmas in the future?  What CFM's are those?

 

Tank size just reduces cycle time.  If you're going to be pounding an air tool for 15 minutes on end that uses a lot of CFM then you'll want a bigger tank to reduce cycling time.  

Mobility is a question too - the larger units aren't mobile if that matters to you - like construction sites you typically want portability, but in that case just size this thing to your needs and get a small cheap pancake for light duty construction, etc. 

 

Noise is sometimes a factor depending on your work area and sensitivity.  

[GeneralDisorder]

You want around 20 CFM for media blasting, painting, die grinding, etc. These have very heavy requirements. You will want a minimum of 5 HP (~4 CFM per HP for a recip). Something with a Baldor commercial duty motor. 80 gallon tank is pretty nominal. Vertical tank models take up the least space.

 

I don't know what tractor supply carries but if they can get Quincy that's probably your best bet.

 

Honestly the best thing to do is get yourself on Craigslist and find a used Quincy QR25 and swap it over to single phase if it's not already. Rebuild the air-end and someday hand it down to your grandkids.

 

Porter Cable makes nothing worth buying. Chinese crap all of it. Amercian iron is where its at for this tool catagory. Get an old QR-325, 5 HP thumper and you'll never worry about air again. Also you can talk over it running in the background since they only run about 700 RPM.

 

GD

Edited December 3, 2017 by GeneralDisorder

[matt167]

If your going to get a portable, get the biggest portable that you can. Do not consider anything that is oil less or oil free.

 

If your looking for larger, get a 2 stage pump. Tank size does not matter as much as getting the best pump you possibly can

 

The Harbor Freight unit, although some will look down on it just because it is from HF, is actually Very good and isn't actually made by one of their regular offshore suppliers.. The Compressor itself is made by Bel-Air and has a tank made in Virginia, the pump is a quality unit from France and the Motor IIRC is actually Baldor.. This unit cost $499 up until a couple years ago but at $800 it is still a deal.

https://www.harborfreight.com/5-hp-60-gallon-165-psi-two-stage-air-compressor-93274.html

[milty60]

Thanks for all the advice. One question that just hit me. What kind of electrical outlet do I need? - standard three prong that's in my garage or do I need an electrician to do some work. 

 

...Milty 

[GeneralDisorder]

I'm a compressor snob so take that into account. Worked as a compressor and vacuum pump technician for about three years at one point. Actually was my last "real" job before starting my shop.

 

Generally speaking, a serious compressor (3-5 real HP) is going to be 240v and will need about a 40 to 60 amp circuit. Generally you will be looking at around 25 amps full load on a real 5 HP machine.

 

GD

[jp98]

Most home compressors are just 15amp 120 volt but there are 220 volt ones also. 

 

Get onto Tractors Supply web site and take a look at what they have to offer and see which one you prefer and then check it out to see if it will meet your needs. 

 

Don't forget hoses and fittings.  For a hose I would go with a 3/8" one over a 1/4" one, the fittings are the same.  Then take a look at the tools you will need to purchase.  A air chuck at the very least.  Then you will want to look at impact wrenches and ratchets to work on your vehicles. 

Edited December 4, 2017 by jp98