|10-19-2005 06:33 PM|
|oldred||Reasly, you are right about the CFM since that is what counts and if it is low not much else matters but you are completely wrong about 2 stage compressors. Two stage units are a LOT more efficient than single stage pumps allowing them to produce more CFM from a given amount of power and they run cooler not hotter. The real advantage of a two stage is CFM and in fact a two stage is Superior to a single stage in about every way, think of a single stage as a car with only one gear. Single stage units are only built because they are simple and cheap to produce thus allowing a low cost compressor that meets the needs for some who have no need for large amounts of air but the advantages of the two stage units are well known and there is just no comparison between the two.|
|10-19-2005 05:41 PM|
|10-19-2005 02:58 PM|
There appears to be a lot of misunderstanding when it come to air compressors and air tools.
The only real advantage that 2 stage compressors have over single stage is air pressure. 2 stage compressors will typically allow pressures in the 175 to 200 psi range. Not only do very few applications call for these kind of pressures, but it takes more horsepower to get there. As to life expectancy, 2 stage compressors generate more heat. Think about it... You are compressing the air twice. Heat is a killer to compressor heads.
The only important factor is CFM (cubic feet per minute). You will find that most air tool manufacturers (except paint guns) don't even give you pressure requirements, only CFM. Ignore horsepower ratings, most of the hobbyist targeting compressor companies have been required to back down from the peak horsepower claims http://www.aircompressorsettlement.com/
Make your purchase decision based only on CFM. Also pay close attention to the rating on the air tools that you buy. Most manufacturers give you average air consumption. Ask for the consumption under load. Here is an example of a very popular 1/2" impact wrench. Ingersol Rand IR231 is rated at 300 foot pounds of torque. It's average air consumption is 4.2 cfm. Looks good, your Campbell 6.8 CFM compressor can do this. The drawback is the 300 ft-lbs is at 22 CFM. The load CFM on the DA will be around 17 (IR311A).
Always buy as many CFM as you can afford
|10-19-2005 12:51 PM|
Kampr, That does look like a good deal for that much money because it looks like the specs are real and not a lot of inflated nonsense. 22 amps is a good bit of power and 17.1 SCFM@90 PSI is pretty good for an outfit in that price range. I think you did ok.
|10-19-2005 12:00 PM|
That's a good point that should be considered.
Like I said before, you usually get what you pay for in compressors.
I paid a lot more for mine than a competitors brand that delivered
the same cfm, The quality difference was substantial.
There's a lot of very low quality units out there so buyer beware.
Always check CFM, the motor amperage (not horsepower)
and what you're really getting, they vary alot.
And make sure it's a brand that's reliable that you can get parts for.
Some of this stuff from China may not be available later on.
|10-19-2005 11:03 AM|
Im sure this topic has been beat to death but my opinion is.... stay away from the CH power single stage compressors.
I have the tractor supply 60 gallon CH power extreme duty compressor
why stay away
1. pumps are junk. I bet my compressor had only cycled 30-40 times when the pump let go. If I remember right the compressor repair guy said its a reed valve pump and the reeds are held in place by cheap rivets. He told me that his company is going to stop dong warranty work on CH compressors because they do SO much of it that they cant keep up.
2. very much underrated.
|10-19-2005 09:27 AM|
That's a lot of compressor for the money, big enough
to handle most anything.
|10-19-2005 08:56 AM|
Anybody interested in a compressor should check this one out. I just bought one about ten days ago. It is a Kobalt K7580V2, item # 134749 sold at Lowe's. I think it is made by the same people that manufacture Bel Aire compressors. I found out that all Lowe's do not carry these. I couldn't even find it on their website. It is priced at $797.00 and I got an extra 10% discount for putting it on a Lowe's card. I think they are still currently having this same deal. Got to pay it off before the interest comes due.
It should be very good for a one person shop.
80 gal. tank
7.5 hp motor (5 hp running)
22 amp motor
17.1 scfm @ 90 psi
15.2 scfm @ 175 psi
|10-19-2005 05:45 AM|
I just bought a new compressor for the reason that I needed the air to
run my DA. It takes 15 cfm @ 90 PSI.
The good sanders typically take that much and you need a large compressor
to run them. Tank size has nothing to do with it, watch the cfm ratings
and compare. You usually get what you pay for in a compressor and I
personally think the Harbor Freight ones are very low quality.
Sears lies about their sizes, Their direct drive 5HP compressor has a
1HP 110 volt motor on it and it screams. I just got rid of mine.
Stay away from the oil-less (direct drive) ones, they're not as durable
and are very very loud.
This is one area where you want to get the best you can, it will last
If you're running air tools you need a two stage.
A single stage will drop below the 90 psi needed before coming on to
pump back up, you'll run low on supply and it will work itself to death.
For just painting with a lower cfm gun they're perfectly fine,
that's all I had for years.
I'm on my 4th compressor now but I believe I got one to last.
It is about 17 cfm @ 90 and it just barely keeps up with my DA.
|10-19-2005 04:03 AM|
I have a single stage Cambell Haus. , cast iron cylinder [5hp. 60 Gal tank]. It will keep up with just about everything except my IR DA, those things are just air hungry, not that it won't do it, but it just about won't shut off. Maybe a more efficient DA out there then the model I have. Not that it won't keep up, but the comp will get plenty hot in the summer which seems to accelerate formation of condensation - good part is I seem to get good dry air by the time I trap the water. Painting is another story. No problems with using the HVLP guns I have - could be wrong, but I think it is rated right around 11 - 12 @ 90 PSI.
If had to do it again, I would go 2 Stage, but I got one heck of a deal on my single 2 years ago at Sears that I couldn't pass it up at the time. Got mine on clearance for $300.00.
|10-18-2005 10:12 PM|
just bought one of these for 869.00 just two hours ago
|02-02-2004 09:39 AM|
"80 Gallon, 7HP, dual stage that does 15.1 cfm @ 90 psi and 13.7 cfm @ 175 psi. "
Like Troy says, if you are planning a lot of body work and doing complete paint jobs, you will need the above power.
I got along with a 5hp, 60gal unit for years but, as soon as I upgraded to HVLP spray guns I noticed a big drop in performance. Spraying panels or doing lite body work is okay for the smaller compressors but, if you are going to do any major work step up the big dog...
|02-01-2004 11:57 PM|
It takes that size to keep up with a DA, or a long board . A good compressor will be classed as a continuous run, meaning it can run for hours without hurting it.
If you don't make mistakes. your not doing anything.
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|02-01-2004 04:22 PM|
what are the big power robbers that you need these big compressors for?? or is it just so the compressor lasts longer since it's only working half as often?
|02-01-2004 03:08 PM|
|Yucholian||Home Depot has a 80 Gallon, 7HP, dual stage that does 15.1 cfm @ 90 psi and 13.7 cfm @ 175 psi. It's Husky and is made by Campbell Hausfeld with 3 year warranty all for $799. I am 99% sure I'll pick one up this week.|
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