Air compressor decision.

[Alexsha]

I've been looking at 2 Kobal air compressors:

https://www.lowes.com/pd/Kobalt-KOB...e-Electric-Vertical-Air-Compressor/1000528965

https://www.lowes.com/pd/Kobalt-60-Gallon-Two-Stage-Electric-Vertical-Air-Compressor/1000542193

I'm having a hard time deciding if adding a 220 outlet and losing portability is worth the 30 extra gallons of air and the extra CFM. General use is the goal with some infrequent painting or air sander use. I have been considering a blasting cabinet though, which makes me lean towards the 60.

Opinions?

 

[txvwnut]

With that low of CFM I wouldn't by either one. I've seen single stage compressors that make the same or more CFM than either of those.

 

[sberry]

Any of the 240v are going to be 2x or more of anything on 120v which are way too small for sanding and painting.

 

[joe_padavano]

With that low of CFM I wouldn't by either one. I've seen single stage compressors that make the same or more CFM than either of those.

^^^THIS! Frankly, I don't understand how any two stage pump can put out that little SCFM. The tank size is not the metric that matters. Buy the highest SCFM you can afford, especially if you plan do use a pneumatic sander or blaster.

 

[Citation]

The 240V numbers are wrong. I think that one is actually like 11 CFM @ 90. If you look at the review pictures some show the label on the compressor.

OP, if you can put up with a stationary compressor and don't mind doing the wiring the 240V compressor is so much more capable. The 60 gallon has a chance of keeping up with something like a sand blaster or higher demand air tools. It won't keep up but if you are OK with the pauses it can be usable. The smaller compressor has half the delivery. That's a big hit. Go for the bigger one. If you really need portable get a really portable compressor.

 

[Alexsha]

Yeah, I don't know why the specs on the 60 are wrong. It's at least 11cfm.

 

[SeisMec]

I think the following is a useful rule of thumb -

Remembering that in compressors over 10 HP in size, normally each HP of motor capacity will generate 3-4 CFM of compressed air at 90 PSI, and under 10 HP you should get 2-3 CFM of compressed air at 90 PSI for each HP of electric motor size.

from this about-air-compressors.com page.

Edit: forgot to include -

FWIW Page two of the manual for the 60 gallon compressor says 7.6 SCFM @ 90 PSI & 230 volts / 17.2 amps.

 

[sberry]

A real comp will do near 4 per hp 2 stage. If a guy is working at journeyman pace at time he can run 3 hp out of air fairly easy. It takes 4 or a pinch over for real body and paint work and since those are uncommon the next step up is 5 and it has just enough reserve a guy doesnt normally need to manage air sanding.

 

[Citation]

I think the following is a useful rule of thumb -



from this about-air-compressors.com page.

Edit: forgot to include -

FWIW Page two of the manual for the 60 gallon compressor says 7.6 SCFM @ 90 PSI & 230 volts / 17.2 amps.

It's definitely an error. The typical "3hp, 60 gallon" compressors claim in the 10-13 cfm range. The sticker on that compressor says 11cfm (see pictures in the reviews). It's definitely not just a 7.6 cfm unit.

 

[Don1357]

The first one is not worth that kind of money, 175PSI is not that impressive a number for a 2 stage unit.

I have this guy:

https://www.homedepot.com/p/Husky-3...table-Electric-Air-Compressor-C303H/206532808

Which gives you the same performance at a fraction of the cost.

The thing is, on the larger unit you could really put those 11 CFM @ 90PSI to a good use sand blasting, but how much of that do you really plan on doing?

 

[Alexsha]

The thing is, on the larger unit you could really put those 11 CFM @ 90PSI to a good use sand blasting, but how much of that do you really plan on doing?

I've got an 86 bronco that I'm going to tear apart and remove rust. Rebuild and paint with bedliner.

 

[nikerret]

Get the biggest (CFM) you can fit and afford. It’s easy to limit output. Pretty hard to get more.

 

[Don1357]

I've got an 86 bronco that I'm going to tear apart and remove rust. Rebuild and paint with bedliner.

I would forego the mobility and get the larger one, it would make you a happier camper. 11CFM may sound like a lot to us home garage guppies but it doesn't even begin to drive a good sand blasting setup. Heck here are the recommendations based on nozzle size:

#2 1/8-inch nozzle: 20 CFM
#3 3/16-inch nozzle: 45 CFM
#4 1/4-inch nozzle: 81 CFM
#5 5/16-inch nozzle: 137 CFM
#6 3/8-inch nozzle: 196 CFM
#7 7/16-inch nozzle: 254 CFM
#8 1/2-inch nozzle: 338 CFM

 

[Den69rs96]

I wouldn’t bother with the first one. I have a 30 gal. Craftsman Oil less with around 6.5scfm at 90. My die grinder depletes it rather quickly and so can my impact if I run it long enough, so I could image that it would be useless with a sand blaster or high volume low pressure spray gun. The 30 gal in your link has even less scfm than mine. The 60 gal would be a better choice.