Air compressors?

[canoetrpr]

I'm looking for some advice on what to look for in an air compressor for hobby use.

I'm not really much of a DIYer but have started doing more maintenance type chores around the house and farm myself.

My planned use is primarily an impact wrench, filling the odd tire that is low on air, a nail gun perhaps. Wouldn't hurt if some day I could paint something if necessary.

I have an idea of what SCFM rating I can get away with (by looking at what the impact wrenches ect. need) but I'm not sure how big a tank I should be looking for. Smaller / portable is preferred so that I can move it around - throw it on the tractor with a generator to go do some fence repairs.

Saw a nice 2HP 4.2 SCFM 5 gallon twin tanks the other day but am not sure if 5 gallon is enough.

Oil lubricated or not?

Any advice would be appreciated.

 

[ray66v]

This topic will likely start another heated debate, at the risk of that, I will make my recommendation based on many years of experience.

The size of the tank on a compressor does not matter. It can be useful and helpful in some circumstances to have a large tank, however the compressor needs to be sized by the output of the pump. If the pump does not have the output to run the tools you need it for, having a larger tank will simply temporarily prolong the inevitable fact that you will run out of air. A large tank can be helpful if you occasionally need to use a tool the uses massive mounts of air, such as a grinder by providing a temporary supply of volume. Using an undersized compressor for anything other than a short period of time, will eventually cause extreme temperatures resulting in wear and considerable amounts of condensation in the air supply.

I suggest you figure out what tools you plan to use, and base your decision on a pump that can effectively supply the volume they need.

If that seems to be a difficult choice, I suggest you choose a budget, and buy the best compressor, (by pump cfm), you can get for that price. Keeping in mind portability, (if neccessary), and electrical supply, (if using an electric compressor).

Oil lube is better for longevity, oil less is better in really cold weather.

There is no problem going big. The only compressor that is too big, is the one you can't get in the garage.

 

[Bird]

Oilless is cheaper, noisier, lighter weight to move around, quicker and easier to repair, will have an estimated 1/10 the lifespan of an oiled compressor, so it'll need more frequent repairs if used a lot. You don't want to run one more than 10 minutes at at time. But for many homeowners, they are adequate.

If oiled, cast iron is better than aluminum. The higher the oil capacity, the better. Even some oiled, but shallow crankcase, aluminum compressors have manuals that say to not run them for more than 10 minutes at a time.

As has been mentioned, don't worry as much about tank size and horsepower ratings as the SCFM rating. If it's rated to move the volume of air you need, and if it's rated to run for extended periods, that's probably all you care about.

 

[canoetrpr]

Thanks for replying folks. A couple other basic questions.

The compressor I will likely buy will probably not come with a hose or many fittings. Is there a basic list of stuff I should be purchasing with the compressor? Figured I would need a blow gun, hose, tire inflator with pressure guage.

How do I figure out what size hose? I've also noticed that you can purchase either a staight hose (like a garden hose) or a coiled up hose that returns into coiled position. Any suggestions?

 

[Bird]

I don't know just how many tools you intend to buy and use, but to start with, I'd go with the 3/8" hose(s) and I prefer the straight ones. I did use short yellow coiled hoses when I was always using them in the same location and never unplugged them. Get an ample supply of male and female quick couplers; number depending on the number of tools you anticipate. A little roll of teflon tape to use on the fittings is handy. At the present time, I have both a regular push/pull truck type tire inflator and a clip on with the built in pressure gauge. I have a regular little short blow gun, a 2' blow gun I use to clean things such as the lawnmower and string trimmer after each use, and a 4' blow gun I use to blow leaves, clippings, etc. from the sidewalk and driveway. Then I have an engine cleaner siphon type deal to hook to the air hose to siphon and spray solvent on engines, but of course I've also used it for spraying herbicides and insecticides. Then there's the 1/2" impact wrench, 3/8" air ratchet, and angle die grinder. Before moving back to down, I had a pneumatic drill, air saw, 3/8" butterfly, pneumatic grease gun, 100# sandblaster, sandblast cabinet, . . . well, you get the idea. There's no end to the handy stuff you can buy and use. For professional use, I'd recommend good name brand stuff, but for most of us, cheaper tools are all we really need. Do you have a Harbor Freight or Northern Tool store nearby. Tractor Supply Co. will cost a little more, and Sears has a pretty good supply of air tools, also.

 

[Blk88GT]

You can never have too big an air compressor, both tank and pump wise.

I started with a 120v "5"hp 30 gallon oil-less Craftsman, and when it finally let go from abuse, I bought a 240v 3.2hp 60 gallon Husky with an oil bath cast iron setup. The new compressor is much quieter than the old oil less one. The longer you use the oil less, the louder it gets and the more inefficient it runs. If you ever take one apart, you'll see why.

One thing, be careful about the HP ratings. Most of the manufacturers have moved to a "running hp" rating, where the older ones were a "peak hp" rating. Look at the CFM ratings, that will tell you if it's a decent unit or not.

I have my whole shop plumbed with air lines all around the walls, and one in the center from the roof. An afternoon worth of soldering some copper pipe and the place is set up. I love it the way it's set up. I rebuilt the old Craftsman compressor for $125 and use that if I need something portable in the house or at the racetrack.

 

[brandoro]

I have a small oil less compressor with a 20 gal tank that, for years, was adequate for most things. Sometimes I had to wait for it to catch up but not too often. One thing that really hurt performance with a 1/2" impact was the 1/4" line that came with it. The impact would only get in two or three good hits before it started to starve for air. The line losses are incredible for small diameter lines. Bird is correct when he says 3/8" line and shorter is better too. If you have a portable compressor that you can have close to the work then keep the air line as short as possible.
I now have a cast iron two cylinder compressor with a 15 amp 240 volt motor and 60 gallon tank, much better. And I plumbed my shop with 1" lines and 1/2" drops so no line losses to be concerned with. I still have the portable that I run with a PTO generator for jobs that I don't have enough air line to reach with the big compressor. Best of both worlds I think.

 

[CinderSchnauzer]

Depending on what Nail Guns you think might be handy, it might be worth taking a look at some of the Porter-Cable Combo units available at Home Depot. At the time I needed a Framing Nailer and purchased a combo unit consisting of twin tank compressor rated 5.2 SCFM @ 90 PSI along with the Nailer. Compared to the retail purchase of the same Nailer separately the cost of the compressor was only about $30.00 Have since added a Finish Nailer and Floor Nailer and Air Chisel.

The 5.2 is probably not adequate for quite a few air tools, however, it is more or less portable and was essentially "free."

 

[RobJ]

This is probably one of those things you will eventually figure out you need 2 of. One larger tank for the shop and one that's mobile. The 5-8 gallon twin tanks are sort of in the middle. I have a 26 gallon oiled that I leave in the shop at the main house. For trim jobs i do I have a nice Dewalt twin tank. About 60 pounds or more so it not real mobile. But would probably work as a full time shop AC. On the trim jobs it'll hold enough air where it's not running all the time. At the weekend place I have an el cheap-o HF pancake oiled AC. Maybe 2 gallons or a little more but it does everything fine up there. Pump up a tire, tractor or ATV, I use it on the air ratchet and impact. Yes it runs more with the small tank but it's fine for zipping off 5 atv wheel nuts. under 100 bucks to. I have an old R-22 tank I converted and can put in parralel with the pancake and get a little more volume.

Here is the little HF model i use at the weekend place..

Harbor Freight Tools - Quality Tools at the Lowest Prices

BTW the BEST small oilless AC I've found is the one below. Loud as heck, but pumps the 3 gallons from 0 to 135 in 45 seconds...AND, AND, AND weighs about 25#. I found one at a pawn shop lightly used for $70. Loved it. Gave it to my Dad because he needed a lighter o ne to carry around.

Westward 3JR70 Oil Less Air Compressor

 

[BB_TX]

I have a 20+ year old Craftsman 25 gallon oil-less. I don't use it very much and it still works as well as when I got it. I have a ratchet, impact wrench, rotary tool, and of course air chucks and blow guns.
Loud, yes. But no more than I use it, not a problem.