air compressors

[benjaminlee06]

Can anyone explain air compressors to me? The more research I do the more I don't understand it. I would love to have an air compressor that I can use to bead blast gun parts, sand blast motorcycle parts, use to paint and also use as an impact driver. What do I do? And what will it cost me?

 

[jrmdeputy]

What you must know, how much of this work will you be doing and how often. Also will you be doing multitasks at the same time that require air? I will be glad to help I have sold compressors as a Snap-On Dealer.

 

[eldirector]

The size of the tank is more important than the compressor itself (in my opinion).

Oilless compressors are inexpensive and low-maintenance. They also are LOUD and tend to be low-volume. These are the common ones you see at Sears and such.

Compressors with a separate motor and compressor (connected by a belt) tend to be a bit more expensive (up to very expensive). They can be much quieter and much higher volume. The BIG ones are 220V, and can move a ton of air.

I have a 30 gallon Craftsman oilless compressor. Can't remember the CFM rating off-hand. Runs my air tools just fine. Loud as all get-out, though. Does pretty much everything I need.

 

[Hajisc]

First you want a two stage compressor head.For sandblasting a 80 gallon tank is nice and 220 volt single phase is easy to hook up.you'll also need a good filter and if you can afford it an air dryer.It's a lot but at tractor supply you can probaby get set up nice for about $1500.
A single stage unit takes too long to recuperate and will not let you blast continuously.Dryer and filter are needed to keep sand or other media dry.@@0 volt uses less energy.
Hope this helps.

 

[hornadylnl]

Forget horsepower ratings and look at the cfm output. Find te cfm requirements for the tools you wish to use and buy a compressor with a bigger cfm rating. Impact guns take relatively little air and usually run in short bursts. I don't know how accurate this is but I was td a 1/4" hose dumping air to atmosphere at 90 psi requires 10hp just to maintain it. Things like blast cabinets require a lot of air. You don't want a cabinet that requires 10 cfm and have a 5 cfm compressor. If you blast for 30 seconds every minute, the compressor will never shut off.

 

[Butch627]

Oilless are loud, and not very durable when ran hard. They are not well suited for continous use. They are best suited for running a nail gun or airing up your tires.

Running on a 110 circuit really limits your cfm. If you are a casual user you probably don't want to run a 220 line and may not want to give up the shop space to a big unit. If you can run off 220 and have the space you will never regret getting the big compressor.

More expensive units generally run quieter. They tend to use bigger pumps and turn them more slowly using the same HP motor. A loud compressor is VERY annoying in a small shop.

When comparing cfm on various units check to see at what psi the cfm is rated. 90 psi is a good measuring point. A more expensive compressor may have a slightly lower cfm rating than a lower quality one. They are meant to give you a fraction less air, but deliver it quieter and for a lifetime.

My .02 the ideal compressor for a serious diy kind of guy is a 5hp 2 stage. I think mine draws 22 amps on 220v. The pump turns very slowly and is quiet enough that it doesn't annoy you in a 2 car garage.

Air compressors don't change much over time. I always recommend shopping for a good used industrial type rather then a new cheapo from Tractor supply or a big box store.

 

[chef larry]

Stay away from Harbor Freight. Go with the largest tank you can afford. Volume is what you need to run larger tools with most air tools rated for at least 90 PSI and see what the CFM for the tool will need is.

 

[Rob54]

There are some good answers here and I agree with them. I would like to add what I have done in my own garage. I moved the air compressor into a small shed like you can buy at any big box store. Just big enough, these sheds are usually used to hold a mower or some garden tools. This moves the noise out of my garage and gives the compressor fresh, cool air to breathe instead of paint or dust filled air in the garage. It also frees up space. I ran power from a 220v breaker inside the garage so I do not need to go outside to turn it on. I piped the air into the garage with a high pressure flex hose (the compressor vibrates and moves while running) and distributed the air through 1/2" PVC tubing (cheap and easy to use). I have disconnects in several convenient places and also added a hose reel from Harbor Freight to the ceiling of the garage. Convenient and easy on the ears! Something that you might consider.

 

[Leo]

That is a great Idea Rob. In frozen climates, be sure to keep the water drains blown out if the compressor room or shed is unheated.

 

[Stang51d]

There are some good answers here and I agree with them. I would like to add what I have done in my own garage. I moved the air compressor into a small shed like you can buy at any big box store. Just big enough, these sheds are usually used to hold a mower or some garden tools. This moves the noise out of my garage and gives the compressor fresh, cool air to breathe instead of paint or dust filled air in the garage. It also frees up space. I ran power from a 220v breaker inside the garage so I do not need to go outside to turn it on. I piped the air into the garage with a high pressure flex hose (the compressor vibrates and moves while running) and distributed the air through 1/2" PVC tubing (cheap and easy to use). I have disconnects in several convenient places and also added a hose reel from Harbor Freight to the ceiling of the garage. Convenient and easy on the ears! Something that you might consider.

I couldn't have put it better myself. The only thing that I would specify is, the PVC that you use should be the schedule 80. Like that gray cressline stuff. The thinner works but I feel better with the thick stuff. I have also used the 1/2" pipe in the past and it will work for most stuff, but if you have a long way to go, of have a decent demand, you may go a little bigger. It makes a huge difference.

If you plan to do blasting in a cabinet, make sure you get more cfm then you think you will need. I have been blasting with something that seemed big enough but wasn't able to keep up. It's a pain in the a$$ and takes forever waiting for the air to build back up. Also works the compressor hard. What I had before was about a 19cfm and it was great. When I moved, I had to sell it and get another because I had to get a vertical one. The one I have now is 24cfm and will even shut down while I'm bead blasting.

Good air and plenty of it is a must in a good shop. Overkill isn't bad if you can afford it or get a deal on it like I did on the last two.

 

[hornadylnl]

Here's the compressor I would like to have.
10 HP, 15 HP, Single or 3-Phase 120-Gallon Vertical or Horizontal Air Compressor : Piston Air Compressors for Sale : EatonCompressor.com

Instead of spending $2500 on one compressor, I'm thinking about getting 2-3 smaller ones and staging them through the pressure switches. I currently have a 6.5hp 60 gallon 10 cfm compressor. If I get 2 more like it, I could set the kick off pressure on the second one at say 90 psi and the third one at 100 psi. During huge demands, 2 or 3 will run and during small demands, only 1 will run. I wouldn't have to power a 10hp motor every time the compressor came on and I'd always have backup air if one failed.

 

[HenryWallace]

Bottom line is tools need oil. Hence oil in the line of the compressor... Which will be most compressors. And oiless compressor would mean that you need to oil your tools.

Blasting requires DRY air. No oil and no Moisture. A good dryer would be needed. A refrigerated or Desiccant style.

Air receiver tanks or air tanks are sized usually with the Pressure and CFM of the compressor. You can have a huge tank and when it hits pressure, will hold that pressure for quite some time. BUT it will take more time to reload pressure with a huge tank and a small compressor. Where as small tanks will be able to be reloaded faster but will lose pressure quicker.

 

[Stang51d]

Here's the compressor I would like to have.
10 HP, 15 HP, Single or 3-Phase 120-Gallon Vertical or Horizontal Air Compressor : Piston Air Compressors for Sale : EatonCompressor.com

Instead of spending $2500 on one compressor, I'm thinking about getting 2-3 smaller ones and staging them through the pressure switches. I currently have a 6.5hp 60 gallon 10 cfm compressor. If I get 2 more like it, I could set the kick off pressure on the second one at say 90 psi and the third one at 100 psi. During huge demands, 2 or 3 will run and during small demands, only 1 will run. I wouldn't have to power a 10hp motor every time the compressor came on and I'd always have backup air if one failed.

Good call!! 2 may even get it but the third will insure it.

 

[Butch627]

Here's the compressor I would like to have.
10 HP, 15 HP, Single or 3-Phase 120-Gallon Vertical or Horizontal Air Compressor : Piston Air Compressors for Sale : EatonCompressor.com

Instead of spending $2500 on one compressor, I'm thinking about getting 2-3 smaller ones and staging them through the pressure switches. I currently have a 6.5hp 60 gallon 10 cfm compressor. If I get 2 more like it, I could set the kick off pressure on the second one at say 90 psi and the third one at 100 psi. During huge demands, 2 or 3 will run and during small demands, only 1 will run. I wouldn't have to power a 10hp motor every time the compressor came on and I'd always have backup air if one failed.

Why do you need all that air?

Ill bet your cost per cfm in electricity will be less with one big compresor than with 3 little ones not to mention the added costs of breakers, wiring and outlets provided you have space in your panel. That one big one will be a hell of a lot quieter than 3 little ones screaming.

6.5hp and 10cfm doesn't sound right to me unless its something you put together with spare parts. How many amps does that claimed 6.5hp motor draw?

 

[hornadylnl]

Why do you need all that air?

Ill bet your cost per cfm in electricity will be less with one big compresor than with 3 little ones not to mention the added costs of breakers, wiring and outlets provided you have space in your panel. That one big one will be a hell of a lot quieter than 3 little ones screaming.

6.5hp and 10cfm doesn't sound right to me unless its something you put together with spare parts. How many amps does that claimed 6.5hp motor draw?

That's why I stated earlier in the thread to pay no attention to horsepower ratings. Look at the cfm rating. Cheaper air compressors are over rated so they'll sell like small engine manufacturers got popped for exaggerating hp ratings. My Emglo wheel barrow compressor is 1.5 horse and will put out 10 cfm. It's 110 and won't run on a 14 gauge cord longer than 25'.

I have a 200 amp 40 space panel with loads of room.

 

[remauto1187]

Yes the HP ratings arent even worth looking at because they are not true. Here is why....

I will use a typical "6.5hp" marked 120vac Air Compressor

1 Hp=746watts

6.5 x 746=4849watts

4849 / 120vac = 40.4 amps

So a 6.5hp motor is drawing 40.4 amps

That "6.5hp" air compressor is drawing 40.4amps from a standard 120vac 15a or 20a breaker through 12 or 14ga wire....Dont think so!

As others have said, its the CFM of your tools you need to pay attention to and how many cfm @ x psi each compressor that "you" are considering buying that you need to pay attention to.

I have a "6.5hp" Craftsman vertical compressor and it is OK for a 1/2' air ratchet but I can outrun the compressor with air ratchet if i am running continuous for long periods of time. If you intend to use big air ratchets, sandblaster or any other high cfm use tools I would go with a 220vac 2 stage compressor with a large tank. You can also plumb in other air storage tanks as well.

 

[Nayls47]

Forget horsepower ratings and look at the cfm output. Find te cfm requirements for the tools you wish to use and buy a compressor with a bigger cfm rating. Impact guns take relatively little air and usually run in short bursts. I don't know how accurate this is but I was td a 1/4" hose dumping air to atmosphere at 90 psi requires 10hp just to maintain it. Things like blast cabinets require a lot of air. You don't want a cabinet that requires 10 cfm and have a 5 cfm compressor. If you blast for 30 seconds every minute, the compressor will never shut off.

Listen to Hornadylnl, You need to know what your tools are going to use in CFM and how many you plan to use at once. Small CFM compressor with big tank means waiting for the tank to fill back after depleting it before you can use it again. Large CFM compressor and small tank could run a tool continuously. A place to check is TSC Ingersoll Rand compressors for starters.

 

[hornadylnl]

We use air grinders at work that require 60cfm. Things like die grinders go through a lot of air as well.

175 psi two stage are nice as well. Almost all air tools are only rated at 90 psi. Regulate it down to 90 psi and you get double the air volume in your tank.

 

[darkkevin]

Can anyone explain air compressors to me? The more research I do the more I don't understand it. I would love to have an air compressor that I can use to bead blast gun parts, sand blast motorcycle parts, use to paint and also use as an impact driver. What do I do? And what will it cost me?

well., now that everyone here has you more confused than you were when you started........................................
as you said, you want to bead blast parts, paint and sandblast some, not run industrial air grinders at a steel mill.
i've been using one of these for years now Shop Kobalt 3.7-HP 60-Gallon 155 PSI Electric Air Compressor at Lowes.com

works great, handles everything i throw at it and more. my DA uses a LOT of air, no problem, paint guns, blast cabinet, avery normal air tool out there, no problem. 500 isn't a lot of money for a compressor and i doubt you'll need more from what you said you need it for.

 

[benjaminlee06]

I did get progressively more confused, but it sounds like there are some basic constraints I can map, starting out with tools I would run and their required cfm. What I am finding out though is it may be a couple of years before I do this. The thing is I would like to do it well, and though I know you get what you pay for, secretly I had my fingers crossed that there may be a short cut to an inexpensive and effective set up that might just take a labor of love and some ingenuity.