Air Compressors

I currently use a low cost one from Harbor Freight and have not had a reliability problem (yet) for home use. I do the same tire swap and light impact wrench work also. My friend, who needed specific pressure and volume numbers, purchased a Sears Craftsman compressor. I don't know the cost, but it gets the job done. I've also used oil-less Porter Cable and DeVilbiss compressors. Both of those are still working fine after many years of home duty service.

I have a Harbor Freight 21 Gallon 1 cylinder compressor. I don't know what you have, but I'll bet it's bigger than mine.

I cannot run any air tools with it and can't even remove lug nuts with an air wrench on a 50 foot hose. My point is I under bought and all I use this compressor for now is airing tires. Not that I work on big stuff anyway.

OP, be sure to buy enough surface cubic feet/minute to do the jobs you have. I didn't.

"I don't know what you have, but I'll bet it's bigger than mine."

You must have had a rough childhood.

What is your high pressure setting on the compressor? There will be some friction loss in a length of air hose. If the air gun is rated at say 90 psi, you need to feed it with a higher pressure at the compressor. Unless your compressor has leaking piston rings, storing air at 120 to 140 should be more efficient. The compressor will run less as you are doing work.

Just in case, have you oiled the air gun lately?

What size is your air hose? If you want to remove lug nuts, you will need to use 3/8" air hose.

The size of your air tank is also hurting you for lug nuts. With that small volume, and low CFM size, the air pressure drops too quickly. If your lug nut does not come loose very quickly, the air pressure reaching the air gun becomes too low to break the lug loose. Try putting an inline air gauge at the air gun and watch the pressure drop. Now remember that there will be further pressure drop inside the gun. I can suggest two ways to help the low volume issue. One is to buy a portable air tank of the type used to air up tires. Fit it with the same style air fittings you are using now, and place it at the tool end of your air line. Then use a short 3/8" air line to your air gun.

The other method is to build your own air reservoir out of PVC pipe, or threaded steel pipe. The steel pipe will have a very high pressure rating, so no problem with 120-150 psi. With PVC, read the pressure rating on the pipe. Give yourself a 2:1 safety factor. A 10 foot section of 6" thick wall pipe will give lots of additional additional volume. If you have a workbench, you can mount as much pipe as you can under the bench and it will not be in the way. A layer of 1/2" plywood between your face and the PVC pipe is a little insurance. (I had PVC pipe in the old shop, mounted high and out of the way. Until I lost my temper and threw a wrench against the wall and hit it dead on.)

"I don't know what you have, but I'll bet it's bigger than mine." Perhaps some exercises in self esteem would help.

Come on now, you just begged for this.

"I don't know what you have, but I'll bet it's bigger than mine." Compressor, Bob, compressor.

"Until I lost my temper and threw a wrench against the wall and hit it dead on.)" Perhaps some exercises in self control would help you!

Unfortunately, you have me confused with someone who actually still works on his own vehicles.

I have 3/8" hose. I need 1/2" with this compressor. Mostly when I'm using the air wrench I break the nuts first.

If it's a flat, I just call AAA and they come out and change it.

Your advice is all sound though, and if I had any initiative, I might take some of it.

PVC for compressed air is a no-no with OSHA -- for the reason you implied. It sometimes goes kaboom.

I don't think mine is bigger than Lynn's but mine works fine. Maybe it's all in the way ya use it?

Maybe his regulator gauge is inaccurate? A tank at the tool end is a good suggestion -- good compensation for compressor inadequacies.

I'd be lost without that satisfying BRRAAPP-zwiiing of bolts coming loose. I'd be walking around all day, feeling on edge.

EXPOSED "PVC for compressed air is a no-no with OSHA".

Even though some people here could not accept this, buried or properly shielded PVC is acceptable, even to OSHA.

True.

The PVC pipe I hit had been in place when I started there in 84. I winged it in 98. It was still in working order when we abandoned the building in 2003.

BTW, did anyone see the Mythbusters episode when they were trying to find the burst point for 2 L. plastic bottles?

As they were walking along, somebody once remarked to Abraham Lincoln, "Look at that Dachshund. Its legs are way too short."

Abe replied, "How so? They reach the ground, don't they?"

This concept can be applied elsewhere....

Thanks for the replys.

I looked at,in some detail,the 3 hp, 10 gallon, 115 PSI model from Harbor Freight.The specs advertised that its air delivery is 5.6 CFM @ 90 PSI and 7.2 CFM @ 40 PSI. This is item #90234.

There is another from Ingersoll Rand,2 HP,4 Gallon Twin-Stack with ratings of CFM @90 PSI 4.3 ,Max PSI 135.Model # P1U-A9.This is listed with Northerntool.Item# 154220.Any further suggestions?

The Harbor Freight model you looked at is essentially what I have, with a 21 gal tank.

You will need to break the lug nuts manually with this compressor. If you plan to use any air tools this is not enough compressor.

Air tools require about 8-10 CFM at 90 PSI.

You might consider an electric impact wrench as Unredundant suggested.

You can live with too much compressor much easier than you can live with too little.

Good luck.

Please forgive me for my thick headednest? I'm also looking @ purchasing the Makita 3HP MAC 5200 oiled lubed pump with a 5.2 gallon tank with a sustaining oprerating pressure of 140 PSI and delivers 40 PSI (6.9 CFM) and 90 PSI (6.5 CFM). I want to be totally sure before I pull the trigger on this deal (a great price) that this A/C will not have enough umph to remove the lug nuts on my F-150 et-al.

That can not be answered because only you know the power of your air gun, and the air consumed by the same. In addition to this, even you do not know how tight the last person did in your lug nuts. If you have something like the newer high powered air guns, you should have no problem. But if you have an old Campbell Hausfield that cost $19.99 when it was new 25 years ago, you night have a problem getting those lugs tight enough, and there is no telling how you will get the lugs off the first time. What I would suggest if you do not know the strength of your gun is this. Take a loose log nut, and tighten it till it slows almost to a stop. Then use a torque wrench on it to find out just how tight it is. Good luck.

The wrench is an"EARTHQUAKE" with max torque 625 ftbs free speed 6600 forward and 6800 reverse.Air consuption 4.7CFM standard bolt capacity 5/8.Will this help in my decision making process/

No F150 gets tightened tighter than 133, so the gun is plenty strong for your use, The compressor is also fine for the gun.

So the only things to worry about are the hose size, the storage capacity, and learning not to snap bolts in two from over-tightening. Good luck with your new toys and have some fun.

Thanks for all of the help that you have given me! Now I'll go and play.

You need to look into the CFM rating of the air tools you wish to use it with. The compressor need to be able to handle the air flow. The size of tank helps some in this regard. In using an impact to remove the nuts it is used in short burst. If the tank is large enough the compressor may have the time in between stops and starts to keep up.

Another good place to find home style compressors is yard sales. How much space you have for the compressor can also be a determining factor. There are some low compressors that will fit in under a work bench, or could be mounted onto a 4 wheel moving type dolly and become portable. WWW.Grainger.com is another place to look. As stated above, the CFM at the working pressure you will use is a good way to compare models. They will generate some heat when running, plan for that. If you run a length of air hose across the cold concrete floor, the air will cool and water will condense in the line, and into whatever you are using the air for. Elevating the air hose and draping it onto things will help. Good luck.

How about a small compressor and an electric impact?

The battery powered impacts are nice to keep in the truck and can also be used to drive a mechanical jack.

An electric impact is good

I used a HF air powered 1/2" which would rip a 3/8" bolt in 1/2

the difference is double hammer. lube is important for every air tool. the air motor being separate from the hammers or reduction on a drill

on the impact linked the front housing is a dead give away for double hammer, very easy to remove the 4 screws and throw in some grease or gear lube. I like moly based grease & not too much.

The hammer(s) and anvil are the heart of an impact. These are the parts that are damaged when a standard non-impact socket is used due to the hardness of the socket.

If you think about it, Impact tools are pretty efficient at storing and converting energy in a compact package.

I pack a Milwaukee lithium 1/2" when I go on the road for product service training. Seems to work fine. Thats why I mentioned electric.

Keep duty cycle in mind. If you are ever going to use it for automotive body sanding with a DA or similar constant use, the pump has to be rated for 100% duty cycle. I bought a $99 Sears 1 hp, 3 gallon, 50% duty cycle. When I used it with a needle scaler to strip wrought iron railings, a common household use _{for me anyway,} it ran constantly while I was working. The cylinder head heated up to the point where the "rubber" impregnated fibrous head gasket melted. I don't think 20 minutes on/20 minutes off is what they had in mind. I had to order a replacement and while I waited, I had some old asbestos gasket stock around so I made a gasket. After a couple of tries to get the reed valves just right, it's been working fine. I just pay attention to work time and periodically stop for a refreshing beverage.

Without knowing your tools, I would suggest 12-15 CFM at 90 psi as a minimum. Tank size can compensate quite a bit, but as mentioned, it won't get you out of a duty cycle issue or a plain too small unit, unless you have a lot of patience. Harbor Freight is not a bad choice if you want to upgrade "some day". It may or may not last you a long time, but when it is done working you may be ready for "some day". I have had good luck with some of their stuff and pitiful with others.

I held out a long time to buy a compressor, because I wanted one to do anything (air tools), I wanted quality, and I was a tightwad. Eventually I was driving by a nice new neighborhood housing development on "garage sale day", so I decided to stop in since I had a wad of cash in my wallet. The tool options were better than a hardware store, and all was quality new stuff with a couple hours on it for a specific job (I love yuppies with large checkbooks). That day I drove away with a Craftsman compressor without a scratch on it for $60. The woman stopped me at the curb and told me she was sure the old man had an owner's manual for it and if I had patience I could have that as well. Five minutes later I had the manual and in the back was tucked a receipt dated 5 mos earlier for $260 + tax!

It only has a 5 gallon tank, but it runs any tool I have ever thrown at it, and it has never had a problem, except the time I dumped it off the bench and broke off the intake filter. Parts were 3 days away, and as I recall were cheaper than I deserved for having done such a stupid thing. I have always had good luck with Craftsman equipment, and that one has been serving my needs without hesitation (including some contracting use) for nearly 10 years. When I was using it for professional painting, roofing, and construction work, I thought sure I would need to replace it, but it kept right on trooping along. It also was invaluable for building my house, which I did entirely by myself, except plumbing and crane work. It has paid for itself many times, and would have had I bought it at full price.

As for your existing equipment, I would check the air consumption on the wrench and meet that plus 50% if it is in your price range. Pay attention to duty cycle. If you are sure tool use is a "homeowner" level and not "production" 50% should be fine. If you think you might cross the line and turn a hobby into an income, go for something with a higher rating. Also, don't overlook the units with the small bullet tanks - they are a higher duty rating, but hold less air. They can be cheaper for the same air delivery, and they have roofed a lot of houses. If you run into a capacity issue, there are lots of ways (some mentioned above) to increase storage capacity for little dollars, but the only way to upgrade delivery is a new compressor!

How you use the compressed air is just as important, if not more so, than what you have as the source of air. I have many years of experience with compressed air, ranging from the designer to the user, and am basing my comments on that.

First, flexible pvc hose is ok for compressed air, pvc pipe isn't. Not only is it extremely dangerous and has resulted in serious injuries (mine included) but it is illegal per OSHA. Once got a free ambulance ride after a section of 2" sched 80 with 80psi in it broke and sent a shard down to the shoulder bone. At that time I was employed by one of the cheapest Co's around with a very autocratic owner. Gave my resignation after the trip back from the hospital.

If you are using the tool on an intermittent basis with sufficient storage capacity you can reduce the volume capacity of the compressor. A 90 psi air impact wrench for example, if it only used 20% of the time and is rated at usage of 8cfm theoretically you only need an average of 1.6cfm to run it. If you operate your compressor/storage tank at 100psi run/130psi off with a filter/regulator set at 90psi your compressor is working and storing most of the compressed air you will be using during the times that the wrench is inactive. The storage tank makes much more than the 8cfm available when you want it. This can easily be obtained from a compressor much smaller than one rated at the full useage of the wrench, 8 cfm. Likewise a small pad sander will probably use more air than something such as an air impact wrench over the same period of time. You use it more per the same length of time than the wrench.

The maintenance of the system and the tools is very important. Tools that bind, are dirty internally, have plugged outlets, have condensate within them or have little or no lubricant are wasting energy and won't run at optimum. Lubricate them as per the manufacturer's instructions. I always lubricate prior to each tools use if it doesn't have it's own lubricator. If operating in cold weather replace the lubricating oil with ethylene glycol (regular automotive anti-freeze). It will both lubricate and remove condensate and ice from the system.

With the lug nuts- many automotive shops run their air systems at a minimum of 140-180psi and don't drop it down with regulators prior to the impact wrench, much higher than necessary and practical. Sometimes you will not be able to overcome this with your properly set system and might need to use a large breaker bar or a "cross" type of lug wrench to get it loose.

I have a 5hp IR, a 5hp Quincy, a 1hp portable on wheels and a 2 gal pancake compressors with 1/2" copper tubing distribution system throughout the basement, garage, shed, etc. Hardly ever use the 5hp's except for sand blasting. Mostly use the 1hp with its 20 gal tank. It is more than satisfactory for lug wrench use, ratchet, grinding, general dusting, and painting use. If it can't keep up I either rearrange the order of the tasks to give the compressor more catch-up time or simply put one of the 5hp's on line with it.

A good example of using smaller compressors with large reservoirs is the PUMKIN CHUNKERS contest at the state of Delaware. They keep the compressors operating putting the energy into storage in large storage tanks until the time that it is needed.

Many others have discussed potential sources. Give the "FOR SALE" commercial handouts a look at. In my area there are always air compressors listed in them.

"but it is illegal per OSHA."

You have made this false statement before. You suggest that PVC pipe cannot, under any circumstances be used in the workplace for compressed air service.

I have no problem you stating your opinion about the rest of the information you provide. I would not use PVC in my own shop, unless it is buried, but that's not the point.

Please don't misquote OSHA to add credibility to your post. Nobody is arguing that it should be use here.

lynlyn-

Without getting into either a "urinating contest" or an oratory debate via the internet: No, you are inferring that conclusion, I am not implying it! If you carefully review the previous references you would see that OSHA states in several places in their interpretations that it is illegal to use anywhere for comp air and also in several other places that it might be used with comp air underground only. OSHA was not misquoted for the sake of "credibility". You are the only one arguing and that argument is based solely on your opinion. If you don't like what you see, use the "DEL" key.

Having shed my personal blood because of some idiot's refusal to do what is safe and practical, I tend to lean towards not taking the risk be it above ground or below ground installation.

Also, having eye witnessed the destructive force of a 2" sched 80 pvc buried pipe with 120psi of compressed air breaking at a joint, I tend to lean towards the conservative when doing risk analysis of compressed air in pvc.

Having spent numerous years in the chemical industry involved with safety and environmental responsibilities including accident analysis (both fatal and non-fatal) I tend to try to keep people away from unnecessary risks. My previous posting was prefaced with "I have many years of experience with compressed air, ranging from the designer to the user, and am basing my comments on that." If that isn't clear enough, what is? Yes, all of it is my opinion, just as all of your reply is your opinion.

Also, I live in a semi-suburban/rural area that is criss-crossed by many pipe lines, both above ground and buried carrying both liquids and compressed gases. As the fire chief of this area I am required to work with these companies towards prevention and mitigation of potential disasters. Having conferred with the professionals involved with these utilities about the subject, they are even more conservative than I am when it comes to risks. They have shown this very clearly in our combined drills and when necessary, emergency responses.

My original posting was intended for the benefit of the original poster. If you don't like it, just ignore it, it wasn't intended for you.

Thanks for your eloquent insight.

http://www.osha.gov/dts/hib/hib_data/hib19880520.html

"OSHA Safety Hazard Information Bulletin on
the Use of Polyvinyl Chloride (PVC) Pipe
in Above ground Installations"

"This is noteworthy because the Plastic Pipe Institute, in its Recommendation B dated January 19, 1972, recommends against the use of thermoplastic pipe to transport compressed air or other compressed gases in exposed plant piping."

...limit the operating pressure of plastic piping distribution systems to 100 pounds per inch (psi) and prohibit the installation of such systems above ground except where ". . . the above ground portion of the plastic service line is completely enclosed in a conduit or casing of sufficient strength to provide protection from external damage and deterioration."

This OSHA document link provided earlier and above does not seem to support your position.

If further reference exists to modify or contradict this document, it would be informative for all to see. Please post link if available.

mjb1962853-

Referencing the same http://www.osha.gov/dts/hib/hib_data/hib19880520.html and the 1972 citation of the Plastic Piping Institute,

It also includes the following information and later (more recent) information:

February 14, 1989
In response to your recent inquiry concerning our regulatory position on the use of plastic pipe for compressed air systems, I trust this letter will clear up any confusion over the issue.

It is our position that PVC pipe shall not be used as a means of transporting compressed air. This position follows the manufacturer's own statements that PVC is unsuitable for compressed air systems. We do allow the use of certain ABS materials that are specifically designed for compressed air systems. One such product is "Duraplus" air line piping system ABS pipe. However, as in any such system, the manufacturer's specifications on acceptable pressure and temperature considerations must be followed.

In closing, misapplication of a product, such as using PVC for compressed air systems, may result in citations and penalties being issued dependent upon the specific conditions.

I appreciate your concern and inquiry into this potential safety hazard.

Sincerely,

SAM A. ROGERS
Bureau Chief

October 5, 1988
It has recently come to my attention that there is a severe safety regarding the improper usage of plastic polyvinyl chloride (PVC) pipe. This pipe is designed for the transmittal of liquids, and is dangerous when used for transmitting compressed air or gas. Unfortunately, PVC has been frequently used with compressed air in construction projects across the country.

The state of Washington has notified the public that PVC pipe is not to be used in compressed air systems. I have also learned that the state of Nevada is in the process of making a similar determination and announcement. Additionally manufacturers of this product advise against its use with compressed air in their catalogue publications.

I believe that it is in the best interests of the citizens of our state if your office would expeditiously make such an announcement. A notice to users of the hazards of PVC pipe - when used improperly - would have the effect of preventing possible severe injury to people who work with or near this product.

By way of this letter, I am contacting the Department of Labor, OSHA, in Washington, D.C. and asking their officials to report to me on actions taken on the Federal level to restrict the use of this pipe and to notify users of the potential hazards involved in improper use of PVC pipe.

Your timely consideration of this request is appreciated.

Sincerely,

DENNIS DeCONCINI
United States Senator

STATE OF WASHINGTON
Department of
Labor & Industries

Hazard Alert

PVC pipe not to be used in compressed air systems

OLYMPIA -- The Department of Labor and Industries warned today that plastic polyvinyl chloride (PVC) pipe cannot be used in compressed air piping systems without the risk of explosion.

When PVC piping explodes, plastic shrapnel pieces are thrown in all directions.

"We're seeing more incidents of explosive failure, and we're citing more employers for using PVC air system piping," said Paul Merrill, senior safety inspector in L&I's Spokane office.

"It's probably just a matter of time before someone gets seriously injured in one of these explosions unless everyone pays more attention to the manufacturer's warnings," Merrill said.

Last year, a section of PVC pipe being used for compressed air exploded 27 feet above a warehouse floor. A fragment of the pipe flew 60 feet and embedded itself in a roll of paper. Fortunately, nobody was in the area at the time.

A PVC pipe explosion in a new plant in Selah broke an employee's nose and cut his face.

PVC piping buried 3 feet underground at a Yakima manufacturing plant exploded, opening up a crater approximately 4 feet deep by 3 feet across.

Only one type of plastic pipe has been approved for use with compressed air. That pipe, Acrylonitrile-Butadiene-Styrene (ABS), is marked on the pipe as approved for compressed air supply.

By law, employers must protect their workers by avoiding the use of unapproved PVC pipe in such systems. Existing compressed air systems which use PVC piping must be completely enclosed, buried or adequately guarded according to specifications approved by a professional consulting engineer.

NOTICE TO EMPLOYERS: If you have questions about the suitability of a material for air system piping, call Labor and Industries at the number listed above for a free consultation.

NOTICE TO EMPLOYEES: If you suspect that a pressurized PVC piping hazard exists, bring it to the attention of your employer. If you do not obtain satisfactory results, you may file a confidential complaint with the Department of Labor and Industries. Complaints are investigated promptly.

ALSO OF CONCERN IS THE FACT THAT MANUFACTURERS OF PVC PIPE AND FITTINGS (Nibco, Charlotte Foundry, etc) ALL STATE VERY CLEARLY ON THEIR PACKAGING AND IN THEIR LITERATURE THAT PVC IS NOT TO BE USED WITH COMPRESSED AIR UNDER ANY SITUATION, NOT EVEN A SHORT TERM PRESSURE TEST OF THE SYSTEM.

Let's not become short sighted by trying to short changing PERSONNEL SAFETY by weaseling around a clear statement that is to improve personal safety and health. The original poster wants to know what air compressor is good for his situation, not read a lot of rebuttal about something that he is probably smart enough to not even consider using in the first place. Back to the original posting-------------

One might be able to "drill down" into the OSHA regs to find some exceptional places such as underground or in shielded raceways where PVC could be used for air. But this is really bonehead. Other correct materials are equally inexpensive and just as easy to work with. I vote with Old Salt; so be done with this dopey controversy.

Ok. I am the one that opened this can of worms. And I am the one that will apologize for the unsafe suggestions that I made.It appears that the op is going to buy a suitable compressor to use, and will not need the additional air volume.

I hereby declare that I will never propose that anyone use PVC pipe for compressed air.

I agree. Using PVC in compressed air service is not wise. Never said it was.

I know that this is late in the discussion, but I will add it anyway.

I wanted the best/biggest compressor that was portable and would run on 120vac. I selected a 30 gallon Craftsman to fill the job, but...

It REQUIRES a 20 amp dedicated circuit and a maximum 20 foot extension cord #12 awg. I can run it with a 100 foot #10 awg extension cord with no problems though.

I setup to paint an outbuilding for a friend, and found out that ALL his outlets were on 15 amp circuits (I use 20 amp for any outlets I wire) so my quicky spray paint job went down the tubes. I ended up doing the job with paint rollers and brush.

Sometimes biggest and best is not the right tool for the job.

Bill

The refrigerator circuit should have been a 20 A circuit. The dish washer, or garbage disposal if there should also have been. Go back and paint it again. This time plug the refrigerator into another outlet by extension cord, and use the good cord to run the compressor.

Very true... in that case I didn't want to go invading the house... changing things around... upsetting his wife... plus that job is long completed.

I'm afraid I am kind of "old school" in that plugs are 20 amp and lighting is 15 amp but then... in a recent project in our house, I discovered that all three bedrooms, both plugs and lighting, are run off a single 15 amp circuit. BAH HUMBUG!!

It seems to me that clothes washers are another source of 20 amp power, but I haven't investigated that here.

Bill

Right, that should also be 20A. Go on, go repaint it.

Thanks for your input.I wound up purchasing a "Makita 5200 Big Bore " 3.0 HP 140 PSI(6.9 CFM)@ 40 PSI and (6.5 CFM) @ 90 PSI compressor on Amazon.I purchased an IR midgrade impact wrench as well.

When it first arrived via FedEx,I tested it on old bolts on a Farmall tractor that I have been working on.I must say, it performed as advertised.We'll see how it performs over the long haul.

Again many thanks to all here,an extraodinary site, the help is much appreciated.

Water is the enemy of your air tools. Remember to lube them well before you put it away. Any moisture left in the tool will start to rust the steel parts. The oil is cheap insurance. Enjoy the world of power tools.