What Size Air Compressor?

[David2011]

It's time to replace my old air compressor. It's a horizontal Craftsman boasting 4 "Craftsman horsepower." There's not even an amperage rating on the motor and it's not possible for a 110v 20 amp circuit to make 4 hp so I'm guessing that the real HP number is well under 2 HP. The replacement needs to be a vertical model and has to run on 110V.

The compressor that catches my attention is the Kobalt "Quiet Tech" 26 gallon unit. Does anyone know anything about this or similar compressors? https://www.lowes.com/pd/Kobalt-QUIE...sor/1001014062

Last time I used the old one, purchased around 1995, it made odd noises and I'm really getting concerned that the tank is at the end of its life. I don't want to find out I was right "the hard way."

[Winger Ed.]

It depends on what you do with it, how hard & often you run it, and how long you want it to last.

Over the years, I've worn out and burned up a few of the smaller ones.
Air sanders, paint guns, and sand blasting takes a lot of air, and tends to over work the small-ish ones.
Now, I'm on what I hope to be the last one I'll need to buy.
It's a 8hp commercial compressor sitting on a 80 gal. vertical tank and weighs about 500 pounds.

Keeping their air intake filter clean and change the oil once a year does them a lot of good too.

[Froogal]

I bought an upright, 60 gallon unit probably 30 years ago. The tank is all steel and the compressor unit is cast iron. Still going strong.

Pay NO attention to the artificial horsepower ratings. Mine is advertised as being 6 horsepower. I knew that was a bunch of you know what when I bought it. It probably is closer one horsepower, maybe two.

What you need to know when shopping for a compressor is to know what the C.F.M requirement of ANY of your air powered tools is, and then buy a compressor that exceeds that requirement. Horsepower means nothing. It is only a marketing strategy. How much air (CFM) the compressor will deliver is ALL you need to know.

[Handloader109]

I bought a HF quiet unit about 2 odd years ago. I can hardly hear it. It is smaller than my old dewalt pancake unit that put out about 120 dB. You couldn't even stay in the same room with that ***. This one is quieter than my 16g Brad gun. They along with others offer some larger units that are decently quiet and work well

Sent from my SM-S908U using Tapatalk

[Mk42gunner]

Tank size and C.F.M. seem to me to be the governing items for a home use air compressor. As noted the HP ratings are a joke.

If you have trouble running your air tools, try to find a bigger hose, more volume available does wonders.

Robert

[M-Tecs]

I don't know about the current oil-free compressors but the older ones are anything but quiet.

https://aircompressorsusa.com/oil-fr...0to%20consider.

I have single stage two-cylinder C-Aire that was purchased to replace a "quiet" oil-free piece of junk. The C-Aire to very very quiet.

[ulav8r]

Replaced the oil in my 2 horse unit yesterday. I think it was due after 30 some odd years. It was purchased at Montgomery Wards and is an honest 2 horsepower.

It is small for some uses. The wife has purchased a small sandblasting cabinet that will require a much bigger compressor.

[BLAHUT]

I bought a twin tank and an upright from harbor freight years ago for construction work. the twin for floor nailing and trim work. figured if they wore out in a few years not a big loss with the price at the time. both run on 110 v. both are still going strong. all depends on what you want to use them for? I have a commercial 5 hp with a 20 Gallion tank that runs on 220v don't even plug it in any more, the other two handle all I need.. and are quieter.

[xs11jack]

Some one got promoted by measuring the start current of the motor on the compressors they were making. The few parts of a second that the motor draws is really high compared to the running current. Most compressor that are made to be run on 120 volts will only draw 15 amps because that is the standard house current. Oh yea, you won't find the running current rating anywhere on the spec. plate on the compressor or anyplace.
Ole Jack

[pworley1]

Get the biggest one your circuit will carry.

[Mal Paso]

Replaced the oil in my 2 horse unit yesterday. I think it was due after 30 some odd years. It was purchased at Montgomery Wards and is an honest 2 horsepower.

It is small for some uses. The wife has purchased a small sandblasting cabinet that will require a much bigger compressor.

If it's like my "Craftsman", it's an honest 2 HP pulling 11 amps X 240 running and was actually made by Speedaire.

I use Milwaukee electric wrenches now, the big one is 1,400 foot pounds, more powerful than my 1/2" air wrench. I downsized to a Makita 1.5HP portable for tires and cleaning parts.

[David2011]

Some one got promoted by measuring the start current of the motor on the compressors they were making. The few parts of a second that the motor draws is really high compared to the running current. Most compressor that are made to be run on 120 volts will only draw 15 amps because that is the standard house current. Oh yea, you won't find the running current rating anywhere on the spec. plate on the compressor or anyplace.
Ole Jack

Yeah, I knew where the horsepower ratings came from. What I don't know is how many microseconds it has to drain that much power but it's definitely shorter than the trip time of an average household breaker. Four HP at 115 volts is about 26 amps. That much 115VAC power is usually only available at marinas and RV parks.

[David2011]

Guess I should have posted the long version. I regularly post too many words. Can't help it. I take after my maternal grandfather who never met a stranger.

More details: Anything that is not semi-portable and requires more than 110/120VAC is too big. The "4 HP," 25 gallon compressor I currently have has been 100% adequate for the past 27 years. If I had a 4000 square foot shop a big cast iron compressor with an 80 gallon tank would still be way too big. I know how to calculate loads based on the air tools I have but I just don't use them to the point of outrunning the compressor I've had. All day capacity isn't significant since all air tool usage is brief. The biggest projects I anticipate at this time would be painting my large scale R/C airplanes. That would be about the same as painting the front clip of a modern car and would be done with a touchup gun because the largest parts are wing panels no more than 20"x60" each.

[Moleman-]

If you're going to use it much don't get an oilless pump. They don't last as long as a standard compressor.

[David2011]

I'll keep that in mind. The current oilless pump has only lasted 27 years.

[Shopdog]

Not counting the large shop 2stage compressor;

Over the years in the building biz,have DESTROYED 1/2 dz + compressor. The twin tank/KV head Emglo knockoffs are pretty durn good. I got a DeWalt labeled version that has been completely adequate. Sprayed 2 kitchens(lacquer/cabinets) with it,on site. It is all this style "wants". Yes,we have all the right HVLP "stuff". Be forewarned,these twin tanks are freakin heavy. But,is the minimum for nail guns and paint guns.

Next up is those 30g vertical style. These are what most of the roofers around here use. They beat on them,HARD for a cpl years and then snag another. We had an "early" version of a Cman 30,20+ years ago,will run two framing guns. That poor thing stayed on the back of my pickup,rain/shine for almost 5 years. Early oiless. Deafening loud but otherwise bullet proof. Sorta rebuilt it and gave it to #3 son. Put out to pasture so to speak. It is a horizontal.... this was before most co's went vertical on this size.

I'd find a vert 30(28,whatever) with the Emglo/KV style head. The green,Hitachi 50' hoses sold at homeboy stores are what most roofers use..... seen these hoses live through absolutely disgusting conditions and keep on banging away. Good luck with your project.

[Shopdog]

One more tidbit on smallish comp.

Two scenarios,illustrating do's and don'ts. Think of a roofer with a nail gun. He's "above" the tank...well above. The moisture being CONSTANTLY produced by this sized outfit is STAYING at the comp. Yes,drain every few hrs.

Second scenario,or "don't"....

Comp. is on the truck,but we're down in a basement framing or shooting cabmets. Here the gun is WELL below the comp. Wonder where all the moisture ends up? Yup,right at the gun. You drain the tank and it's like,"cool we're having a great day" because there's nothing coming out the drain. Looking at your guns innards,you'll know where it all is.

Gravity plays a HUGE role in where the moisture ends up.... so stack the deck,and use this to your advantage.

[Scrounge]

If you're going to use it much don't get an oilless pump. They don't last as long as a standard compressor.

I'm another who wouldn't bet on that. Mine is a Campbell Hausfield 20g tank, and I've had it 23 or 24 years. I know it will die one of these days. Maybe even today. But I bought it to fix my 77 Plymouth Volare when it welded a bearing on the front right axel. It was going to cost about $1K to have it fixed, or I could buy the parts and tools, including the air compressor and air tools for about $800. Wife asked if I'd still be able to use it after the car was fixed. When I said yes, she said get it. When it starts up in my shop, which is the former back porch, it scares her to this day, but she's happy to to have compressed air whenever we need it.

[GregLaROCHE]

I have a small compressor that works for filling tires and spray painting, but I’m dreaming of one that could power my air tools that have been put I storage for twenty years. I have seen some setups with up to four compressors on top of a volume tank. For some reason I don’t want to trust them.
I have a three phase 4hp motor that I have thought of using. However, the cost cost of the compressor is not that much, but when you add the volume tank, regulators and fittings, the price gets up there. Plus there’s all the work to do to put it together. I’m wondering if I shouldn’t just buy a cheap Chinese one and expect to throw it away in a few years.

[johnsonian09]

My father purchased a 60gal husky (or craftsman..?) compressor from HD probably when I was around 8 years old. Still works, despite both his and my antics. It’s on wheels, I repainted my wife’s c30 with it several years ago..

I think no matter what brand you buy the larger motors are more reliable.

Hell I bought that baby Ryobi 1 gallon battery powered 18v/4 amp bat to run some 18 gauge nail guns at customer houses. Shoved it inside an old stackable husky box lined with insulation and plumbed the hose thru it. You couldn’t hear the thing running in the box. And that works great years later despite the name of, and color of it.

Any of the Big box store 30gal+ will take tires off a car and paint small projects, run nailers etc. And if you decide you need more capacity to run tools longer you can open up the regulator, attach a extra inline tank, then regulate that tank down to your tool pressure and you’ll trip the motor less.

I know roofers who just run a pancake compressor and a tank. I think they are about 15- 20 gallons but I’m not sure.

If this is for yourself and not for a production crew, does waiting an extra 30seconds for the thing to run pressure back up really matter?

If this lives in your garage and not in the truck bed:

The advantage of the bigger ones, is that they are usually worth fixing. And there’s someone local you can pay to have it done if you don’t want to DIY.

The advantage of the small ones, is if it breaks 5 years in, you’ve typically already made that money back out of it and you can just replace it if fixing it is out of your league or just don’t want to.

I haven’t heard of anyone local using kobalt tools. Looks like it would last several years and the reviews aren’t bad. And I don’t think you’ll regret getting that one.

I had a dewalt that looks similar and approximately that size, first day ripped the drain valve right off the bottom when transitioning from uneven asphalt to a wheel chair ramp. Blew the valve to god knows where. So if your valve is in dead center on the bottom of your tank, depending on how much it juts out you may want to spend the 20$ on a valve relocation kit with a short and tight 90 elbow , which also just makes it easier to operate slightly and less likely to forget you need to Drain the thing if you can see the valve.

Run a small tube into a old milk jug to catch water and empty it when it gets half full. Doesn’t cost any time to drain the water out when your done, and your tools will thank you for it in longevity.


Sent from my iPhone using Tapatalk