Air Compressor Questions

[9_Mile]

I'm looking for a portable electric air compressor to inflate tractor tires, as well as occasional air tool use. I have a Kubota 4630 with R4 tires, which are pretty good sized. What makes sense for:
- Tank capacity; i.e. how many gallons
- Pressure / CFM ratings
- Motor HP
- Other features
- Accessories

I see a fair number of 4 to 6 gal. portables rated around 135 psi / 5.3 scfm @ 90 psi. Will these do the job?

Recommendations?

 

[InlineDieselFan]

If you want to use an air tool (impact gun, air ratchet) or two I would look at the 20 gallon tanks with a 5hp motor as the minimum. This is what I have and I can run out of air just undoing lugnuts on the truck. The small gallon tanks just don't have the air reserve capacity to power up tools excpt for things like air nailers.

30 gallon 7.5hp is about the size limit of the portables.

Once you get an air compressor you will most likely wish you had a bigger one. Kind of like tractors and pick-ups.

steve

 

[Boondox]

Depends on your definition of "occasional" when it comes to air tool use. I have a little twin-tank Porter-Cable compressor that works great for inflating tires, blowing off machinery, and using nailers or staplers. But no way can it keep up with my air wrench! So now I have the little compressor (which I like because it only takes about 45 seconds to fill the tanks) and a big 60 gallon 240V unit for using air tools.

Pete

 

[BIGUN]

I would get the oil lube type compressor. I like them better and they are supposed to last 3 times longer than the oil free type. I never run short of air with this compressor. I had a 2 HP Craftsman for many years and it served me well but would run a little short of air using an air blow gun continuously.
Don’t know why you specified a portable but I bought an upright stationary model at Lowes, which I really like.
Stationary
You can run a 100 ft of hose to your tractor for very little money. If you buy this type and don’t want to bolt it to the floor you can leave it bolted to the shipping pallet making it very stable.
If you really need a portable, I like this one.
Portable
I really like this air blow gun for cleaning the dust and grass off my equipment.
Air Blow Gun

 

[Egon]

As others have stated:

Get the most CFM you can afford. The requirements of a tool seem to expand once one is acquired.

Try and find one with cast iron cylinders.

Egon

 

[Soundguy]

Depends on your air tool use.

If it were for just doing the tires.. those little 2 gallon pancake compressers really do a good job.. even work good for low volume tools.. like staplers / nailers.. lots roofers use them.

For more air tool use.. I would suggest either getting a bigger unit.. or have an aux tank.. like a 5,7,10 gallon tank.. like wall mart sells.. and plumb it in to the smaller compressor / tank.. let it charge up.. then you have decent air for intermittant use.

I do this with a 2 gal pancake comp, and a 7 gallon campbell housefield tank... runs a 3/8's air gun to take lug nuts off... Byt the time the last nut is off.. tank is pretty low.. but fills up ok.

Harbor freight generally has those on sale for about 89 bucks.. hard to beat that...

If you need more than casual air use.. I suggest you go with one of the 10 gallon units on a roll around cart...

Soundguy

 

[BIGUN]

One thing to watch for with the small portable aux air tanks is their limited lifespan. They are made of thin metal, I suppose to make them easier to carry and reduce cost. At least some of them have a warning label to dispose of the tank after a specified number of years. The reason being, they rust from the inside especially if not drained regularly, weakening the tank, then can explode when pressured up. I have seen pictures where this happened to one in the bed of a guy’s pickup while airing it up at a service station. Luckily he wasn’t injured. So if you use one of these follow the directions concerning the lifespan of the tank.

 

[Soundguy]

Yeah.. as with any presurized tank.. there -is- a definate life span.. and due care and maintenance will help prevent problems. I drain my tanks and check my oilers regularly.

Soundguy

 

[higgy]

Yea, it is exciting. I was doing some grain cutting for a guy down the road as a favor when I got a leak in the front tire of my combine. He said pull it to the shop and I will fill it for you. It was a 5 hp 10 gallon oil type compressor, hevy thing. He plugged it in and walked away to the bench to get the air chuck and I was still in the cab of the combine when the tank ruptured. The whole compressor was sent into the air, in fact the compressor went way above the top of my combine as I was able to see the thing crash into the ground after having the **** scared outa me.

If you calculate 120 per square inch and the weight of the compressor you start to realize that there is a LOT of potential energy stored there that can do a LOT of damage.

I showed him the vlave on the bottom, I think it WAS the bottom, of what was the air reciver. He said "I allways wordered what that was for" !!!.

This time we were luck. I use my compressor and air hogs now.

 

[zuiko]

I would get a small couple gallon pancake type compressor, then if you need more air for some tools, I would get a large oiled stationary compressor.

I have a 20 gallon oil-free compressor that I think is the worst of both worlds. It is very loud, a pain to move anywhere, consumes more power than I have available on many circuits, but also doesn't have enough air to run a lot of tools.

Either way I would get a compressor, the ability to use air tools (esp nailers) is great.

 

[Soundguy]

I agree.. I don't like those oil less compressors. This little pancake job I have is 4gallon 2hp.. I think I had it backwards when I posted earlier.

I think the guy that had the tank explode might have had a cutout fail or something...

In the shop at work, we had an older 60gal compressor fail ( 5hp motor died).. Found it was 40$ more expensive to get a new campbel hausfield 60 gallon compressor, than to buy a new 5hp motor... we decided to get the new one.

In the meantime, we stripped the old compressor of the other 60gallon tank, and plumbed them together. Now the compressor runs a bit more in the morning . but then runs less during the day. Really powers our big 1" air gun nicely...
Unit is 2 cyl oiled.. pumps up to 135psi.. does it quick too.

We installed valving to seperate the tanks. etc.. has oiler/dewaterer, etc.

And they were going to junk that old compressor...( I was actually hoping they would... as the compressor worked nice... I was going to get some belting and either rig a pto setup for it, or use a belt pulley off my jd or cub to run it for shop air at my house... oh well...)

Soundguy

 

[higgy]

The cut out mayhave failed as the compressor was running when it happend.

How ever in this case there was no question that the tank had rusted to the point of failue. Once the tank started to split the rest failed. When examining the damage to the air reciver the areas areound the failure were well on the way to rusting through. Do not forget that condensation can lead to a fair amount of water pooling in the tank, which are not painted or protected from rust.

I also am a fan of oil type compressors as I like to be able to maintain my tools.

A good compressor, while more expensive at first will last longer, can be rebuilt and should cost less in the long run. It is possible to fine oil type compressors in all sizes.

Now, if I could just get a rotory vain or twin screw compressor in my shop! /forums/images/graemlins/grin.gif

 

[BIGUN]

I don’t think at lot of people respect the amount of stored energy in a compressed air tank. It is basically a bomb sitting there and of course the bigger the tank and the higher the pressure the greater the potential danger.

Any new factory-built air compressor should never rupture from the cutout switch failing if the tank is in good shape (not rusted, etc.) because they all are equipped with a safety pressure relief valve. They are sized for a flow rate that exceeds the capacity of the compressor. If the cutout switch fails to open the safety should lift venting air from the tank faster than the compressor can pump it in, preventing any serious overpressure of the tank. With lawsuits what they are today, could you imagine any manufacture selling a compressor not properly equipped with a safety valve?

Many manufactures recommend testing this valve periodically by pulling on the small ring attached to the safety. Be aware this will be a noisy experience and the safety may leak after testing, requiring it to be replaced in order to stop the air leak. This would be preferable to having a bomb go off in your shop or garage though. /forums/images/graemlins/smile.gif

 

[Slamfire]

I did just what you suggested, I had a 4 gallon, 2 hp compressor for nailing. When I got tired of wrenching, I picked up an 11 gallon portable tank and a 1/2" impact wrench. It will usually, but not always, remove one bolt from the tractor wheels before the wrench stalls out from lack of pressure. I'm in no real hurry, but I'd sure like a 5 hp 20 gallon rig.

 

[Tonester]

Hey Soundguy (or anyone...)

While we're on the subject, I have an Ingersoll Rand T30 60Gal in my pump house that is nice but I seem to always need the air when I'm nowhere near the compressor! I would need, for example, at least 300 feet of hose to do the roof on our new run-in shed. A fellow I know offered me a nice chunk of change for it (he knows I rarely use it) it's in new condition. I was considering replacing it with a portable from Quincy Compressor for the same money:

Four cylinder single stage cast comp. with "splash lubrication"
8HP Honda gas engine, 3/8" Norgren Regulator
17 Gal ASME tank, 18CFM @100PSI, 16.9CFM @125PSI
Wheelbarrow style w/two decent wheels

I'll be using Drills, Nailgun, Air Blower, Sprayer, Wrench & Hammer
(one at a time mostly). The guy at the shop thinks it may be available with a bigger (30?) tank, but wasn't sure.

i would hate to sell myself short, but the portability is nice IF the unit will cut the mustard. I don't know if this helps 9-Mile, but it sure looks like a nice unit.

Any comments?

Here's their web page, 9-Mile!

 

[hockeyhead]

Now, that's a truly portable compressor. Those numbers will run most anything you can throw at it. What do they want $$ wise? I have the Home Depot special $399 Campbell Hausfeld, twin cylinder, single stage, 60gal. vertical, 6hp electric, cast iron sleeved cylinders I am happy I bought it, it is 8 years old and is has not failed me. I run a 1/2 impact, 5" grinder, straight die grinder, 90 degree die grinder, 3/8 ratchet, 1/2 drill and a stapler with it. I will have to wait for air if my impact is working hard, or running that 5" grinder. It produces 9.3 cfm @ 90 psi. I have replaced the oil 3 times in the 8 years and I drain the tank atleast every third month. I expect it to last another 8 years. I debated the same brand and better brand dual stage compressors for some time before I bought, but could not justify the cost for my use. It is not portable, I now have 235ft of hose( 4, 50ft, 1, 25ft, and 1, 10ft) and will buy or borrow more hose if the latest project requires it.
there is nothing lost in running a long air line on your place. As far as tractor tires go, an $29.95 , 12volt compressor will solve that if you are stuck out back with a flat, or a portable air tank will work also. Bottom line buy the largest compressor you can justitfy (cfm rating @ 90 psi) thats what air tools run at.
The same compressor I have can still be had at TSC or lowes on sale for $439 and it will last with proper care.
Now if my needs required a portable that gas powered unit discribed sounds pretty good, but no 2,3,4,5, hp pancake compressor fits my requirements. happy compressor hunting

 

[Rch]

air compresser 101

This is the best dicussion re air compressors I've seen. It cuts through the hype. I brought an oiless 12 gal de Villbes which also makes the Sears units. It's loud and generally too small for air tools. It's only virtue is it portability and initial price. I try to buy the right thing the first time. This is a perfect example of flunking that goal unless you have very limited plans. /forums/images/graemlins/crazy.gif

 

[Soundguy]

</font><font color="blue" class="small">( Any new factory-built air compressor should never rupture from the cutout switch failing if the tank is in good shape (not rusted, etc.) because they all are equipped with a safety pressure relief valve. They are sized for )</font>

I was thinking more along the lines of an old compressor 'out in the barn'.. the thing is old and dirty/coroded.. cutout fails.. and so does pop-off valve.. due to age/dirt/muddaubers.. etc.

Just guessing... though obviously as we saw was metal fatigue / cosrrosion in the tank.

Soundguy

 

[slowzuki]

Don't buy an oiless direct-drive if is going to live in the shop with you! I want to shoot mine! I have a Cambell Hausfield "5hp" upright

It can do everything I want except sand blast and paint. The die grinder does make it wheeze though.

When looking at units, take the amps the motor is rated at, multiply by the volts then divide by 746 to get the "ideal" hp the unit can develop. The actual will be about 10% less. My "5hp" unit is actually like 2 hp which explains it being so weak!

 

[Bird]

</font><font color="blue" class="small">( I brought an oiless 12 gal de Villbes which also makes the Sears units. It's loud and generally too small for air tools. It's only virtue is it portability and initial price. )</font>

Well . . . , it does have one other virtue; I can completely rebuild one of them in less than an hour. /forums/images/graemlins/wink.gif /forums/images/graemlins/laugh.gif