Air Compressors

I will be setting up shop over the next 4-6 weeks (read weekends). The only major tool I need to purchase, outside the toolkit, is a compressor. Since I have never owned one before, I could use some advice. I'll start out with a few requirements/statements.

1. Must be 120v. (Even with 120v I may need to upgrade electrical)

2. Garage is not attached to house.

3. Working mostly nights and weekends

4. Oilless or Oiled??????

5. What Pressure/CFM should I look for.

6. Any luck with Lowes/Home Depot compressors or should I stick with Sears.


Thanks,

Greg Piney
RV-8 Gonnabe (Fall '05)

PLEASE consider upgrading to 220V. Most 110V compressors are marginal at best.
If you buy an "oiless" you will start kicking yourself within seconds of turning it on. Can you say "NOISEY"?
Don't be missled by HP ratings. They are worthless. Look for max cfm at 90 lbs.
A two stage is more costly but MUCH quieter. It runs slower and will last longer. Also the larger the tank the better. The compressor will run less.
I have a 5 hp compressor that puts out 18 cfm @ 150 lbs.
You probably don't need this much but I mention it to reference many 6 hp compressors on the market today put out less than 10 cfm at this pressure.
Sears has gone offshore to buy their compressors now and sell the same machines that Home Depo and Lowe's do but at a higher markup.
Mel...DAR

220 would be great, but I have a 110 from Lowes (6hp, 25 gal variety) that was relatively inexpensive (~$350) and works great. It handles priming fine though i wouldn't paint with it. I forget the cfm: more definitely is better, but mine doesn't have a whole lot. However, if you have an oil-lube/belt-driven one the noise when it kicks on is really no big deal to me. Some 110V can be rewired for 220 later if you should choose to do so, so you might look into that as a compromise.

If you are at all handy with tools and like to build (other) things, I would argue for a smaller compressor (like I have) on wheels that you can move around. Just this past weekend I used a nailer on it to build a shed. Since it was a ways from my house, I really could not have used a big stationary tank (located in my garage) with the nailer... short of having a couple hundred feet of hose.

Happy shopping.

6.4 CFM @90PSI is not enough...

I agree with Mel here. If you have to upgrade the 110VAC to the workshop, consider going with 220VAC. If that's out of reach, do try to get the maximum CFM at 90 PSI. I have a two cyl (cast iron, oil lubricated) compressor with 5HP 110V motor and 25 gal tank. The system is rated for 6.4 CFM at 90PSI. This is not enough. When deburring with a die grinder, or drilling a ton of hole (wings) the compressor runs constantly. I bought a bead blaster to clean some steel parts before priming, and the compressor really does not run that setup well at all. I paid $450 for the compressor and I wish I had gone with something that will do at least 12CFM at 90PSI.

Can you build a plane with a less expensive compressor? Of course. But if noise is a concern, you may have to either put your money into an insulated and ventilated box or a better compressor. Also, a smaller CFM compressor may slow you down if you use air-hogs like air sanders, rivet grinders or die grinders for deburring. If you plan on using electric drills and the compressor is just riveting and running a pheumatic squeezer, you can use just about anything.

My motto with all my tools, is buy quality and buy it for life, instead of buying two or three cheaper models, but I'm a tool freak. I'm building a new shop, and I will spring for a better compressor, and have to sell this 5 year old for a fraction of what I paid, false economy IMHO. With beefier compressor I will be able to use just about any tool for any job.

Good luck with yours.

I certainly can't argue with the recommendations to buy up, but...

My only comment about 220V compressors is to say that 220V may or may not be available to you once you move to the airport. At the city owned (and wired) hangars here, 220V is not an option. I bought a convertible (220V to 110V) model, that I run at 220V at home and will convert back to 110V when I make the move. Running it at 220V doesn't make it more powerful (produce more air), it only helps in that it consumes half the amps.

I have an upright oil-lube model I purchased from HD, and have been very satisfied with it so far. You can see it here. I do wish it produced more CFMs, but to get more CFMs required a 220V only model... I comprimised.

i've gotten by, so far, with my trusty little craftsman 1.5hp, 3 gal. home compressor for dimpling, squeezing rivets, cleco'ing, and some air drilling. i bought this for home use (bike and car tires, etc...), and it has turned out to work well for what i've done so far. i think i paid about $120 for it at sears, but upgraded the hose. i believe it puts out 4.5cfm at 90psi. i am not planning on doing my own paint, so this works well for me now. for much larger drilling projects, like when i start on the wings, i'll either upgrade to a larger compressor for air drilling, or use the electric or cordless, which has worked very well so far too. i have an electric rotary tool for grinding.

it depends on what you plan to do with it. if you are gonna paint, and use the air die grinders and such, you'll need a much bigger tank and cfm rating.

This is the compressor I have and it rocks! It is VERY quiet and will pump enough air to paint a car or plane. You can easily talk over it while its running. It uses 110V and is worth every penny.


http://www.sears.com/sr/javasr/product.do?BV_UseBVCookie=Yes&vertical=TOOL&pid=00919541000

I just bought the same Craftsman model that Jeff is showing. It works great and is very quiet. It's all you are going to need for the project. I strongly recommend against the oil free models. Had to replace a 15 gal oil free model that was obnoxiously loud and had a hard time keeping up during major drilling sessions (wings). Finally died after cutting the canopy. Cylinder cracked. Should have bought the oil model in the first place. My 2 cents.

110v verses 220v information

RV7Factory said:

Running it at 220V doesn't make it more powerful (produce more air), it only helps in that it consumes half the amps.

Your right about that, but don't get the idea it's cheaper to operate on 220.
It still consumes the same amount of watts on either voltage.

Power (watts) = current (amps) * volts.
We are billed by 1000 watt hours. (kilowatthours)

You can't get something for nothing.

Mark

Click to expand...

Air compressor

I bought a 5hp 110v compressor with a 30 gal tank at Lowe's for $379. See
http://www.wideopenwest.com/~glaesers/RV7A/Workshop.html

I have a 3X rivet gun an a pneumatic squeezer and have had no problems. The compressor does not run very much, and the noise is reasonable. You can barely hear it inside the house, or outside if the garage door is down.

Dennis Glaeser
7A Wings (getting ready to ProSeal my first tank in a few days...)

Mark, to pick a nit... when operating on 240volts (to be accurate) you will see a better power factor (due to less inductive lag) with the higher voltage setup, so apparent power (P=EI) is actually different that TRUE power as observed at the load.


You will have slightly better economy with the higher voltage due to less inductive lag. It still won't produce any more air, though!

Sooooo, forget I said anything!

Mark Burns said:

RV7Factory said:

Running it at 220V doesn't make it more powerful (produce more air), it only helps in that it consumes half the amps.

Your right about that, but don't get the idea it's cheaper to operate on 220.
It still consumes the same amount of watts on either voltage.

Power (watts) = current (amps) * volts.
We are billed by 1000 watt hours. (kilowatthours)

You can't get something for nothing.

Mark

Click to expand...

CJ

Click to expand...

Mark & CJ...

Eggsactly!

My point about the less amps was that you might find yourself tripping breakers if you run a large 110/120V compressor on the same circuit as other things. So if you have to dedicate a circuit to the compressor, might as well make it a 220/240V circuit... whatever the number is!

So far, the Sears compressor looks like a winner. I did see a nice vertical, oil-lubed 120v compressor at Lowes last night. I will need to get the specs off it and compare it to the Sears.

I failed to mention that the garage I will be building in is not mine. It is my Mother-in-Law's. If I upgrade the power, it will only be to improve the available amps. Right now, if I turn on the Drill press or Band saw, the lights dim. Any improvement will have to be on my dime with her approval. She rarely gives me a problem on things like this. If I have to bring in an electrician, I would probably have a small subpanel put in with 2-3 breakers and minimal rewireing.

Greg Piney
RV-8 Gonnabe (Fall '05)

Building in you Mother-in-law's garage say you. Sounds like you've got bigger problems than which compressor to buy.

Good luck!

gpiney said:

So far, the Sears compressor looks like a winner. I did see a nice vertical, oil-lubed 120v compressor at Lowes last night. I will need to get the specs off it and compare it to the Sears.

I failed to mention that the garage I will be building in is not mine. It is my Mother-in-Law's. If I upgrade the power, it will only be to improve the available amps. Right now, if I turn on the Drill press or Band saw, the lights dim. Any improvement will have to be on my dime with her approval. She rarely gives me a problem on things like this. If I have to bring in an electrician, I would probably have a small subpanel put in with 2-3 breakers and minimal rewireing.

Greg Piney
RV-8 Gonnabe (Fall '05)

Click to expand...

I did that same comparison and the specs are pretty much the same. I liked the vertical better for lower floor space.
If the lights dim when the drill press is turned on, I do suggest another circuit. My garage has a couple of circuits in it - one for the lights and another -GFI- for power. The GFI only went to the bathrooms and outside plugs (the GFI unit was in the box in the basement), so I tapped into that one since it typically has nothing else on it. Works great. Since you're typically only using one power tool at a time, any lightly loaded circuit will do for tool power. I hooked my added lights to the garage light (different circuit) so they turn on/off with the switch. The added lights can be turned off independently as well (fluorescents with a built-in pull chain).

Dennis Glaeser
7A Wings

RV7Factory said:

Building in you Mother-in-law's garage say you. Sounds like you've got bigger problems than which compressor to buy.

Good luck!

Click to expand...

Actually, my Mother-in-law is a sweetheart. Can't say the same for her daughter.

Greg Piney
RV-8 Gonnabe (Fall '05)

DGlaeser said:

I did that same comparison and the specs are pretty much the same. I liked the vertical better for lower floor space.
If the lights dim when the drill press is turned on, I do suggest another circuit. My garage has a couple of circuits in it - one for the lights and another -GFI- for power. The GFI only went to the bathrooms and outside plugs (the GFI unit was in the box in the basement), so I tapped into that one since it typically has nothing else on it. Works great. Since you're typically only using one power tool at a time, any lightly loaded circuit will do for tool power. I hooked my added lights to the garage light (different circuit) so they turn on/off with the switch. The added lights can be turned off independently as well (fluorescents with a built-in pull chain).

Dennis Glaeser
7A Wings

Click to expand...

That is what I was planning to have done. Lights on one 15amp circuit, Tools on one 20amp circuit.
Have to clean the place out first then label all the outlets.
Any electrician should be able to figure it out.

Greg Piney
RV-8 Gonnabe (Fall '05)

I 10th the 220V

Get 220V, it is easy to wire if you don't have a plug.

Get a cast iron cylinder, wet oil crankase compressor, it can be rebuilt and will last a lifetime. The cheap-O ones are not going to last and the compressor section of the oil-less ones are a throw away. Don't scrimp here. In fact don't scrimp on any tool. IN general if there is a tool that cost $36 and another for $18 that is suppose to do same thing get the $36 one, you will regret getting el-chepo. G

Name Brands???

Are any particular name brands consistently better than others? Or do you just shop by performance/features alone?

I bought the Sears Craftsman. Reasons:

a) Price was right
b) Nice aluminum jugs that are steel lined
c) Parts are easy to come by, they are all online

I am pleased with my decision.

CJ