I have a small compressor, but it obviously doesn't have the output to do some of the things in the garage that I plan to do. I've been looking at the 'required cfm' outputs on sprayers and da sanders, and although the requirements vary, they obviously require quite a bit of air. My question is this: If I want to run a da sander, sand blaster, or spray a car, what compressor should I buy? I don't have an unlimited budget, so I'm looking for the minimum requirements I should look for?
I had a single stage that put out 14 cfm@ 90 psi, with a max psi of 115 and it would barely keep up to paint. I now have a twin stage 29 cfm@ 125 psi, with a max psi of 175. And I love it..... I would say buy the the biggest you can afford or have room for...
I have a 6 horsepower single stage "Puma" that runs on 220V. It's not quite enough for sandblasting using a "medium" nozzle in a TP gun because it runs constantly and overheats after about an hour, so I have to take breaks to let it cool down once in a while. It usually can keep up with die grinders, but runs almost constantly if you're porting heads or something for hours. I do most of my sanding by hand with longboards, so I don't know how well it works with a D/A sander. It's fine for painting a car with my Sharpe Cobalt HVLP spray gun. It kept up no problem, but it puts a lot of moisture into the line when it starts to run warm, so I use about 40 feet of galvanized pipe with downtube drains and a moisture trap and a big DeVilbiss desiccant dryer tank. When I did my first candy paintjob, I put 11 coats on in one day and never had any problems with the compressor. One tool that seems to use a ton of air is my 3" cutoff wheel. The compressor runs constantly when I use that tool -- maybe because it's a piece of junk Campbell Hausfeld. You might want to spring for a 2-stage if you think you'll need a lot of air. Mine is adequate and has lasted me about 10 years. The other thing might be to make sure you look for better quality air tools that don't use as much air. The air consumption of good quality tools like Ingersol Rand is a whole lot lower than the cheap import brands. Good luck.
there's no such thing as "big enough" when you're shopping for a compressor. I have an older good sized two stage compressor that will keep up with a fresh 1/8" sandblasting nozzle, but lags when the nozzle wears bigger. (yes, i've been looking for a carbide nozzle to replace it)
It's like six or seven hp. Of course this is where it starts to really add up $$$wise . You can run two in tandem but you need to parallel them instead of series to make them ACT big. I have given this some real thought but I am a little drunk.
This info is just what I was looking for. Looks like you can't buy a compressor that's too big, just too big for your budget. And the tip on shopping around and comparing air supply requirements when buying air tools might be a really good tip. I've compared some on the internet this morning, and the air supply requirements for the same type tool vary greatly. Thanks for all the info guys. If anyone has anything to add, my ears are always open.
I agree, you can never have big enough. I have a 7 1/2 hp, 2 stage, 80 gal one and it rocks! 23 cfm at 125 psi. Oh yeah baby. I love my compressor... no not in that way. You sick people.
Yep, these guys got it right. Buy the highes CFM output you can afford. Take sometime to shop around for a good used one. You can usually get a decent deal on a good sized compressor. Just don't do what I did and get a 220v 3 phase when you only have single phase in the garage. D'OH!! Now I gotta swap out the motor to a single phase and that proving to be a bit pricey for a new set-up. I'm scrounging around for a used motor.
I would say you need at least 20cfm @ 100 psi for most shop applications. The only way to get that kind of productions is with a 2-stage pump. Mine is 22cfm @ 175 psi ; I have a regulator/dryer at the tank regulating the pressure down to 90psi, in effect nearly doubling the CFM output. It kicks on and shuts down in about 90 seconds running any shop tool - blast cabinet, HVLP spray gun, plasma cutter, die grinders, etc.
I got a smokin deal on a monster AC about 5yrs ago. It's a 10hp Speedaire on an 80gal horizontal with a 125gal vertical tank plumbed in as well. It's 35cfm @150psi. It was 3ph and that was no problem at the shop when I had it. Now I have it in my barn at home on single phase with a farm duty 10hp 1ph motor. I have just under $1300 in the whole gig. I was going to sell it and get just a single phase 5hp for home use but I had so little in it the $$$ spent on the motor was still cheaper than replacing it with something "normal". To my way of thinking it runs less time than the 5hp would so I'm saving $$$ with the big one. From dead empty it runs about 5-6min to fill 205gals to 150psi. It cyles on @125 and runs for 1min 15sec to shut off. I can remove and replace 4 wheels and tires with the impact and it very seldom even cycles for a job like that. It will catch up to 2 DA sanders and shut off. So how do the rest of us pull of a deal like that? Keep your eyes and ears open for a body shop goin outta buisness. You might try to look for a commercial AC service company that sells reman units as well. You need the highest CFM rating you can logically run. The motor was $650 out the door at Grainger. Another tip...when you're at Grainger to buy something ask the write up person for a discount. I have a Ford employee badge cuz of my job (but I don't work direct for Ford and they don't care). That's good for 15% right off the top. They will usually go as deep as the computor will allow them too after that. This is not bullshit. You never know what you can get if you don't ask. GO BIG!! Good luck with your search.
you already got advice on sizing......25 or so cfm... my 7.5 Belair will actually outrun my sand blast cabinet and shut off.....however, i don't expect it to do that with a larger blaster..... i picked mine up on craigslist.org .....be patient, some old commercial (rebuildable) compressor come up there all the time and for some great deals..... i had just bought mine off of craigslist and two weeks later i was at a college auction......120gallon 35cfm per compressor and the tank had TWO independent Quincys...both had spin on oil filters, and oil pressure guages....went for $375 for the whole deal!!! i didn't but it cause i had just spent the mother load on a lot of other things.......wish i could have.....i could have used the 3 phase motors to build 3phase generators and for that price i could have easily justified a new baldor 10hp 220v motor.....anyway......you know how it goes..........i did get the fella's # though
Mike they make what is called a Phase converter My buddy has one for his Bridgeport and for his compressor. they sell them at Tractor Suppily around here. An electrictan would know exactly what i'm talking about.
As noted - it will never be too big. You can buy 2-stage compressors at Lowes and Home Depo, but they are not the same as buying a Qunicy, Dayton, Ingersol, etc.. I'd recommend 2-stage for anything - at least 5 horsepower. A compressor of this size will handle all the air tools - even a long-board bondo sander or a DA. Sand or media blasting is another cat altogether - you'll probably have enough CFM for small jobs, but you probably don't want to spend anywhere near the amount of money it takes for serious or continual work. Also - the bigger the tank, the more chance the air has to cool and more of the condensation will stay in the tank. I highly recommend that you buy a really good in-line filter --> one of the ones that takes a replaceable "cartridge". You can get away with some water in the line with air tools (at least if you oil them after use), but it is bad news for paint work. I have a "temporary" small compressor - that puts out about 10 cfm at 90, but will replace it with a bigger 220 volt unit this coming year. I'll probably buy a smaller 2-stage Ingersol Rand commercial unit - the cost is about $1100 - shipped to the dock. Checkout eBay and lookup a "T30" unit - 5 horsepower - will give you some idea what these compressors cost. Dale
Not much will keep up with a sandblaster, I use a trailer type, compressor, like the kind used for jackhammers. I think its 95cfm. But when I have the blaster going, and a air fed hood, plus few little leaks at fittings, it wont maintain much more than 60-70 psi. I've used a 175 IR, that's about what is needed.
I've heard mixed reviews about phase convertors. The bad I've heard is that they suck more electricity than single phase does and that the initial draw under demand is enough to dim the lights in the neighborhood. And the cost is about the same as a single phase motor. I haven't done any real research about this yet so I'm a little ignorant of facts. Anybody care to edjumicate me on phase convertors? Thanks!
I looked into it for my 10hp AC. It woulda cost all in around $1150 to get it to run and once the tech data was sorted it woulda run slower (6.5-7hp) and amp draw was pretty high. I threw the notes away about 3months ago so the specifics are unclear. Max amps on the 1ph motor is 42, a 5hp would be 22-28A. The 5hp would run way more hrs throughout the year so what would I save/spend to go all out with the 1ph 10hp motor? Well I threw those notes away too but I save about 1/2 or more in operating cost due to the higher capacity of the pump. Phase convertors are ok for lathes and bridgeports since most of the heavier work is done with reduction and the draw is less, but with an AC, no way. Holy shit ...kinda long-winded way of saying in this case you're right
I did the same as Highlander .... Picked up a 1998 3phase Champion 10HP compressor ... Cheap. Rated Something like 37CFM at 100psi. Has an oil pump and roller bearings etc ... Picked up a new 1ph 10HP Baldor motor for like $600. With wiring and panels I'm into the whole thing for about $1400. Plenty of air for whatever I do ... 120 Gallon tank. Goes from 0 - 190 psi in like 4 minutes. 100 - 190 in about a minute. Catches up and shuts off in just a few minutes when blasting.
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