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Anyone have an opinion on the best bang for your buck air compressor? Advantages - disadvantges? Why is cfm more @ 40psi than 90psi? How often would would you be using 40-50 psi instead of the max. the compressor is rated for? Is it dependant on the tool being used?

Mugsy,

I'm no expert but I'll share a couple of thoughts. First, you'll use lower PSI when painting and higher PSI when media blasting or using air tools. You'll want higher CFM if you're using air tools that will run more than short bursts (like media blasting). While horsepower may be important, I think the tank size is more important. The bigger the better. I think the bigger tank supports more CFM. I'll take the back seat and let the experts take it from here. I currently use a 6hp, 80 gallon tank and it's great.

Jerry

Jerry's compressor is great. You can do almost anything with one like that. I have a 2 HP compressor. It's OK for painting and running an impact wrench, air ratchet or flanger, but it really isn't enough for continous running of a sander, nibbler or cut off tool (you have to let it catch up). The only advantages over Jerry's is that it's portable and plugs into a standard 110 volt outlet. E.g. We took it over to a friend's house and ran a nail gun off it while helping him frame up an addition.

At a lower pressure you have more air flowing.
Think about putting your finger over the end of a water hose. Higher pressure less water/air with your finger there. take your finger off and you have lower pressure but more water.

Buy the biggest air compressor you can afford. I'm always wishing I had more. Shop around, prices vary alot.
There's my 2 cents,
Scott

Think of the "most" cfm's of air you think you will need for you tool requirements and add half that much more and you will do well. As for me I use a 7hp 80 gal. vertical Craftsman Professional that has 175psi and 17.9 cfm. I run my Skat-Blast cabinet off of it and it really does well. The way compressors are priced around here it was a good buy for $800. I shopped all the stores and with it on sale plus the extra 10% discount with Craftsman club it was the best buy going. I really wanted a Quincy but they are pretty expensive. Runs fairly quiet and handles about anything I can think of needing. For a good explanation of air compressors and what works or what you might need go to the tptools web page and read for a few minutes. Well worth the time.

So to run a larger compressor like an 80 gallon putting out 15 cfm, am I pretty much looking at 230V? If so, how hard is it to run a 230V hookup here at the house? What's involved?

This is great - now I know what I want for Christmas - a new compressor. The biggest one Binford makes!

Back to reality: if you have as electric stove and/or clothes dryer, your house already has 240V circuits. The previous owner of my house plugged his 240V tools into the dryer outlet while the shop was being built. The local hot tub rental guys use the same trick. A 60 Amp subpanel was eventually installed in my shop. The first thing to look at is your existing panel - is there room to add more circuits?
If you have installed 120V circuits before, 240V isn't too tough; it's basically 2 hot wires instead of 1.

No such luck Gord. Gas stove, gas dryer, house built in 1948, circuit breaker panel installed in 70's. I got two maybe three available spaces in my breaker box.

Sounds like you might need a new panel.

Electricians routinely upgrade/replace panels and should be able to give you a ball park estimate. Get the size of the main breaker (I am guessing it will be 60 or 100 amp)and the manufacturer of your existing panel. Tell them the size of compressor you are considering.

Or you can make do with a 120V compressor and rent a big one when you need to do sand blasting.

I was afraid somebody'd say that. We're getting ready to do an addition on the house so I'll talk with the electricians when they're here.
Thanks all.

Yet another $.02 here. My advise is to shop around and around. Look at what you need and what will last. I settled on a single stage Ingersol Rand 80 gallon 5 hp monster. It does max out at 135 psi, but I get 18.1 cfm at 90, which is very solid. My blaster, sander, grinder, etc. have never starved for air. Even with the sandblaster, it shuts off shortly after I stop. I reach my limits on what I can take before the compressor does.

Watch for a cast compressor rather than a sleeve or an all aluminum compressor. You want something that will last. Look at duty cycles too. Mine is designed to run nearly 24 hours a day.

Mine came from Tractor Supply store, and with the 10 percent discount was $629. Like I said, shop around and don't rule anybody out.

I have a Craftsman 6hp 30 gallon vertical that I am about to inline with a 80 or 90 gallon air tank that I got from work. Would that be a good idea or would that be running my compressor a little hard to fill the tank?

jlv,

I'm guessing you've got the oilless variety like I bought the first time. Your limitation is what the machine can put out. I think you might get about 6 cfm at 90psi, which could leave you wanting more if you plan on heavy aplications. Impacts, ratchets, etc will be ok, but sandblasting, grinding, and sanding will leave you very disappointed. Also, heavy and steady use will preobably be the end of your compressor.

If you were closer, I'd offer to give you a deal on mine. Once I got the big one, the little guy just sits there looking sad.

I recently bought a Campbell Hausfeld Iron Force compressor from Lowes, the one with the twin V pump and a 60 gallon tank. I got it because it gives me enough CFM to do everything from blasting to painting without a large power draw, I figure the motor is about 3.5 HP. My shop is about 180 feet from my house panel and I didn't relish doing a separate drop or running a really large wire out there. So far I have been very happy with it, of course it wouldn't do for continuous professional work. Chipmunk's Craftsman sounds really good and a good price.

About jlv's comment...

I have a 5hp 21 gallon compressor, and just found that it's not quite enough for my new HVLP paint gun. It's impossible I get a new compressor at this point, won't another air tank in-line with the output boost the CFM?

I realize the safety concerns, but if I used a tank rated for the pressure, isn't this an option?

I'd like to hear if anyone has done this. If so, what are the low cost solutions for the second tank.

Thanks!

Another tank won't change the cfm, that's limited by the compressor. Linking two compressors with a manifold could do what you need. My neighbor had two smaller units and hooked them together. It worked for him.

Two tanks together would give you a bit more lead time if you let it run up to pressure, but then you still have more space to refill once it goes down.

If you are planning an addition and only have a few spaces for breakers left you need to upgrade your panel anyway. Even a small addition will require numerous circuits. Have them upgrade for your shop requirements too. You can run the wire to the garage yourself.

Another compressor in parallel is another consideration I mulled over, but it makes sense that the down-time would still be a semi-problem.

I have a Harbor Freight 5hp 21 gallon unit (probably more like 2.2 hp from what I understand). Two of these would probably be enough to squeak by - and I'd have to make sure I can supply anough amps for both running at once with the lights on.

I'm leaning toward renting a REAL 5hp / 60 gallon for the main panel painting depending on the rental rate. Anyone know off-hand what rental rates usually run? Also, is this size compressor a 220v unit?

For perhaps 90% of the painting (time-wise) that I need to do, my small detail gun should be adequate (door jambs, dash, small parts, etc.). So if I prep the exterior and get all masking done - a couple of days of panel painting should about do it.

Thanks for any advice on the subject.

For instance, 5 hp 230 volt single phase motor draws 28 amps,if you see one that draws less amps, you aren't getting a true 5 hp motor.Most residential compressors are now over rated,take a 3 hp motor,relabel it 5 HP, hope the consumer doesn't run it continously.

Gasoline powered air compressors are available too, like from Northern Tool, if 230V is out of the question for your shop. If you have an old V motor hanging around it is pretty easy to convert one into a big compressor, just use one cylinder bank to run the motor and convert the valves and manifolds on the other side for air. All the CFM you will ever need.

Truckedup: You are absolutely right about the HP ratings of these compressors. Free air CFM of my 2 HP Speedaire is 5.8 @ 100 psi. There are "5 HP" units at the local tool store that can barely keep up to it. A true 3 HP motor needs 230V.

Well, just an update. I was gonna wait 'til we were well into the house remodel before buying but, the Sears ad in the Sunday paper got the best of me. They are offering no payments-no interest 'til Oct 2005 so they snagged me. I decided I liked the portability factor and bought a 25 gal., 175 psi, 2 stage Craftsman Professional for $400. I ran a d/a sander for a while today after setting it up and it seemed good. It's surprisingly quiet too. I'm gonna use the heck out of it for the next 3-4 months and if I'm still happy with it, great. If not, I'll take it back and swap out for the 60 gallon, 230V.

A better question is, when would you ever use the maximum? Most air tools are rated at 90 for the performance they advertise.
I'm guessing that this is the one you have.
25 gal compressor specs
$399 on sale.
At 90 psi it can deliver 5.1 CFM. If the DA you mentioned came from Sears, it uses 5.0 CFM. At 175 psi max, the compressor probably kicks back on at around 150. Once it does, it will never stop again until you do. Even if you have a water separator on the tank, the hot air will cool in the air hose, the condensed water will spit out of the DA exhaust. You oiled the DA, so you will have black oily water on everything.
That compressor can only manage 5.6 cfm at 40 psi. This HVLP gun that sears sells needs 7.0 CFM@40. Try to paint with this on a hot day and you'll put more water than paint on the fender. And don't forget the black oil.
This would be a better sears compressor 6hp (phony rating), 15Amp same as the other 3 1/2 hp. This one is $20 less, twin piston, single stage, but gives 8.6 CFM@40. It also delivers 6.8@90.
You can get by with this one and get good results for a $379 investment.

Several of the other compressors mentioned are nice enough for their prices, but they are 220volt.

Yep, that's the one I bought. I looked at the other one and saw the cfm's were rated higher. 3 things made me go for the one I bought. 1. It's vertical and space saving. 2. This puzzles me but, the rating (Sears has a general rating on air comp., 1-10, 10 being best) on the other was 6 and the one I bought 7. Maybe 'cause it's a single stage vice two stage and 150psi vice 175psi? 3. The guy I spoke with in the tool dept. said he thought the cfm was over-rated on the other and probably closer to what I bought.
The D/A sander I purchased says average consumption is 4 cfm. Can't I install an inline filter/lubricator thing close to the tool to cut down on water intrusion?
I bought a paint gun today and was able to paint quite a bit before the compressor kicked in. Did some metal lawn chairs in enamel and they turned out pretty nice.
I'm gonna have the electricians wire up some 230V stuff for me when we finally get under way with the house remodel. If I need more air, I'll cross that bridge then.

The D/A is rated at a very low duty cycle. I suspect you'll take frequent breaks, but that's not all bad.

Even if you do decide to move up later, you're up and running for now!

Go get 'em!!

I'm not sure where you had in mind for the location of an inline lubricator, but keep in mind that anything after the lubricator such as a hose section will be contaminated. It's safer to put a drop of oil in a tool periodically. The inline "filter" is a good idea.
Many, many years ago I painted a number of cars with a small compressor, similar to the twin piston I mentioned. It takes a lot of prep to overcome its shortcomings. I used three inline filters connected together on a belt behind my back. A four foot hose connected to the spray gun. Air filters(intake air) are a problem with these small compressors. They are too small and clog easily. I made up an adapter to connect a four inch flex hose to a remote mounted ten inch car air filter. Actually all compressors have filters that are too small . I have that same setup on my big compressor now.
You have to paint with the compressor is as cool as possible. That means all clean up of garage and car has to be done the evening before and then shoot early.
It's a good idea to use the moisture filters for any sander if you're using them for very long.
Painting lawn chairs is not the same as painting a truck. Wait till you've painted the inside of the bed on that 3/4 ton. You'll think you just painted 20 lawn chairs and wonder why you didn't buy enough paint for the rest of the truck. HA, HA

About the capacity and life expectancy of that oilless compressor. Are you going to listen to that tool "expert" at Sears or the other guys here that said they've been there and regretted it.

I would run three 220 lines to the garage. One to split off for extra 110 outlets, unless you already have a sufficient amount now. One 220 for a welder. If you were to get a real compressor, it has to be hard wired. It will also need a fused switch and a mag starter. Have the electrician run flex conduit and pull the wires later, when you need them.

Wait, that's stupid. Run one 220 line into a garage subpanel and then wire what you need later.

Yet another update. After realizing my house has been upgraded to a three wire system, I decided to shell out another $80 and get the 60 gal. 240V belt driven Craftsman Pro. 10.2 cfm @90psi (double the cfm of the one I returned) for $80 bucks more seemed good.
Got it wired up today (After paying $50!! for a Zinsco 20A 2 pole breaker) and it wasn't nearly as loud as I thought it'd be. The other compressor that I exchanged, boasted 40% quieter but, I couldn't hear the difference.
It's definitely got more umph than that 120V. Really made that sander go. Can't wait to get started on some bodywork and framing my new garage and painting lawn furniture and...

One thing I would add: I would not reccomend an oil-less compressor, they seem to have a fast wear cycle. I would stick with an oil type compressor. 220 volt would be best. Also look for an air compressor that is slower running (rpms) wise. A slower running compressor runs cooler and creates less water.

I agree 100% with White Lightning. When the oil-less compressors came out, everyone was jazzed. I bought one, but if I had plugged it in at the store, I (and half of Fremont, CA) would have run for the exits. Really, really NOISY. Sounds like a machine gun going off. My neighbors used to complain (not to mention the near heart0-attacks my wife had when I left the pressure switch on and she went to the garage. . . emptying the dryer . . . .BANG!!! BANG!!! etc. . . Way to loud. I like "pocketa-pocketa".

Now I have a new 6 HP, 220V, vertical tank unit with wheels. Can't plug it in just anywhere, but I can move it around and it gets the job done without ear or other (heart attack!) damage.

Mugsy,
here are my two cents on the panel upgrade. I have been through a number of additions, doing a good part of the work myself. There are a number of ways of making incremental improvements in the electrical, to give you just what you need. However, the process usually repeats and you are usually better off to go to the ultimate configuration right away. I say this because some people think that the contractor is just trying to sell them something they don't need, when they suggest a service upgrade.

This summer I will be building a 28' x 40' shop. I currently have a 5HP, 30 gallon Craftsman compressor that I've had for over 16 years and it has worked admirably for what I've used it for...but it's time to upgrade. I've been looking around and am targeting the Porter Cable 175 PSI, Two-Stage 80 Gal. Oil Lube Stationary air compressor . Cast iron, 2 stage, plenty of volume. My shop will have a 200A main breaker panel so juice will not be a problem.

An 80 gal tank is nice,but you have to have a compressor that will really put out.If you add another tank to a small compressor it will take it forever to reach maximum PSI.If you need or want that much CFPM go out and buy a unit that is set up for it.

Dale937,

I'm confused? The compresor I wil be purchasing is designed for the tank it mounts onto. 2 stage compressor, cast iron, etc. I guess I guess I don't understand your statement??

Burgie,what you are getting sounds fine.I was referring to someone hooking up a second reserve tank to a small compressor
It will work but it will take a long time to get the pressure up.Hope this clears it up.

Dale937,

Yup...that clears things up...my mistake. Must be too tired from the past couple weeks of 75+ hours per week working

Was over at Lowes the other day.I see they have a Casmpbell Hausfeld,80 gal,2 stage,7 1/2 horse compressor for $745.Oh yeah its an upright.

Burgie,

You won't regret going to the 7-1/2 HP compressor. I installed one about a year ago. I had used a Sear 6HP oil-less prior to that.

The difference when sand-blasting is like night and day. I can run my blast cabinet constantly at 80psi and the compressor runs less than half the time. Before, I would have at most 45-50 pounds at the cabinet and the compressor would run constantly.

It makes the whole process of cleaning parts a lot less like work.

I purchased the 7hp/80gal upright compressor from Lowe's about three months ago. I looked several before making the decision to purchase the Husky. It will produce 15.1cfm @ 90 psi, ideal for blasting. I can sand blast until I'm fatigued and that thing will keep up. The best $750.00 I have spent on a tool in quite some time. It will run about anything you would want and then some while doing your truck project. I bought a 5hp/30gal upright that produced 12cfm @ 75 psi originally to do my blasting. It has been relegated to doing the projects that require less cfm and more portability. If I had to do it all over again, I would have spent the money for the 7hp/80gal upright right off the bat, but I thought I might get off a bit cheaper with the smaller unit. Don't make that mistake. Buy the biggest unit you can afford that will provide the cfm/psi needed to do the job properly and efficiently.