Compressor and air tool question

-
E

EP87

Guest
Really starting to get going on my 70 duster complete restoration,
and finding out the compressor I've got just won't handle tools like DA sander and the angle air grinder for any length of time. My current compressor is a Husky(home depot) 25 gallon 5.5 peak Hp with a rating of 3.5 cfm at 90psi.
I've decided to get a larger compressor and been looking at 60 gallon compressors at Home depot, lowes, and Harbor freght, that all run about $400.00 they all seam to be rated at about 10-11 cfm at 90 psi.
My question is will these do the job, the info on the compressor very, some saying these types of tool can be used and others say Intermittent use only.
I don't want to spend much more then this, if I don't have to.

thanks in advance for any input. Richard
 
Get the largest compressor you and youre situation can afford!!! A DA Sander requires a LOT of air. I had a Sears 220V 90 gallon tank, forget what cfm if was.. but, point being I wore it out! I have since switched to a gas powered 9HP 30 gallon tank putting out 18 scfm. I got it used for $900. I'm much happier now, wish I would have bought it the 1st time.
 
Figure out which tool has the highest cfm rating that you are going to use. If the DA sander uses 6 cfm and this is the tool that you will use that has the highest cfm then I would add about 2 -3 cfm minimum more for a compressor size. Make sure that you use the same pressure/cfm rating when you do this. As pressure goes up cfm goes down and visa versa. If your tool is rated a 90 psi then get the 90 psi rating on the compressor. Some of the cheap compressor companies use the cfm at freeflow to sell their compressors because at freeflow (0 psi) a compressor has the most amount of cfm. This makes their compressors look like they will do the job but won't.

Chuck
 
It takes more gas powered HP to turn a compressor than an electric motor HP. This is because gas engine hp has a curve while an electric more does not. A 9hp gas motor is the same as about a 5-6 hp electric motor. But don't concern yourself with HP it is another thing cheap compressor companies will use to sell their product. CFM and at what pressure is it rated at is all you need to concern yourself with. Higher effeciency compressors take less HP to run than lower effeciency ones do. Two stage compressors are one of the most effecient. Like most things in life you will get what you pay for in a compressor.

Chuck
 
I use a 6 hp / 60 gallon Campbell Hausfeld. It is about the best you will do until you step up to the 2 stage, which starts at about double the $400.00 amount you have been talking about.
I have stripped with a DA 3 or 4 cars completely, in addition to spraying and everythinh else I do, about 10 years old and no complaints.
When buying the 5-6hp 60 gallon units, there are several, many use a one piece aluminum pump that is not rebuildable, I recommend the cast iron pump, as in my C/H it comes with a manual listing part numbers for every single part. Best of all, I got it at WalMart for $369.00, they still have them, only about $389.00 now.
 
Get a oil lubed pump, not an oilless. Oilless won't last long and will overheat under continous use. Plus they are noisy as all hell. Like was stated before get the biggest one you can afford/space. It's best to check out the actual pump assembly for service parts and availability. The tank size is a factor but not as important as pump size and output. As you can always add a remote tank if your needs require it. Cast iron pump body with cast iron sleeve, I have seen pumps listed as cast iron but they had aluminum sleeves. I would suggest also the best regulator and filter you can get, along with a automatic tank purge for removing the water trapped in the tank. And check to make sure it has a good sized outlet, not just a 1/2 inch hole only.
 
lawndart360 said:
I use a 6 hp / 60 gallon Campbell Hausfeld. It is about the best you will do until you step up to the 2 stage, which starts at about double the $400.00 amount you have been talking about.
I have stripped with a DA 3 or 4 cars completely, in addition to spraying and everythinh else I do, about 10 years old and no complaints.
When buying the 5-6hp 60 gallon units, there are several, many use a one piece aluminum pump that is not rebuildable, I recommend the cast iron pump, as in my C/H it comes with a manual listing part numbers for every single part. Best of all, I got it at WalMart for $369.00, they still have them, only about $389.00 now.
Click to expand...

I'll think I'll look in the this Cambell Hausfeld, since it looks like I can get parts for it.
 
lawndart360 said:
I use a 6 hp / 60 gallon Campbell Hausfeld. It is about the best you will do until you step up to the 2 stage, which starts at about double the $400.00 amount you have been talking about.
Click to expand...

Just a point of interest. An electric motor on a compressor that plugs into a standard 120v outlet can not produce anymore than 2.5 HP period. Unless the company is violating all the electrical codes and safety standards in the country the most current the device can draw is 15 Amps. 15 Amps converts to 1800 Watts which conversts to 2.5HP.

Most new construction has 20 Amp service which would allow 3HP but to use the full 20 Amps requires the plug on the device to be different (one of the blades is 90 degrees to the other).

The way they come up with these high HP numbers is they do what is called a lock rotor test where they prevent the motor from turning and see how much current is drawn. For a 6HP number it would be 37 Amps. This test is performed as a requirement for UL safety certification, they do it to ensure something bad does not happen like bursting into flames. It has no bearing on how much power the motor is producing when it is running.

So what I am saying is do not even pay attention to the HP rating on a 120 volt compressor since no matter what it says it will only produce 2.5 HP when it's running or you will be popping breakers all the time. And this also means that a 120 v compressor is not going to be suitable for running most air tools.

A large capacity tank will give you more run time before the compressor kicks in but you will have to stop using the tool until the pressure comes back up.

The only thing to look at is the cfm rating at pressure compared to the tools needs.
 
dgc333 said:
Just a point of interest. An electric motor on a compressor that plugs into a standard 120v outlet can not produce anymore than 2.5 HP period. Unless the company is violating all the electrical codes and safety standards in the country the most current the device can draw is 15 Amps. 15 Amps converts to 1800 Watts which conversts to 2.5HP.

Most new construction has 20 Amp service which would allow 3HP but to use the full 20 Amps requires the plug on the device to be different (one of the blades is 90 degrees to the other).

The way they come up with these high HP numbers is they do what is called a lock rotor test where they prevent the motor from turning and see how much current is drawn. For a 6HP number it would be 37 Amps. This test is performed as a requirement for UL safety certification, they do it to ensure something bad does not happen like bursting into flames. It has no bearing on how much power the motor is producing when it is running.

So what I am saying is do not even pay attention to the HP rating on a 120 volt compressor since no matter what it says it will only produce 2.5 HP when it's running or you will be popping breakers all the time. And this also means that a 120 v compressor is not going to be suitable for running most air tools.

A large capacity tank will give you more run time before the compressor kicks in but you will have to stop using the tool until the pressure comes back up.

The only thing to look at is the cfm rating at pressure compared to the tools needs.
Click to expand...


I checked my electrical service box last night and its got plenty of room for the bridged breakers for a 220v connection and is right next to were I plan on putting what ever compressor I end up with, and I've wired for 220v before
welder, dryer etc. so going with a 220v compressor shouldn't be a issue.
 
Well as the saying goes, go big or go home. Mine is a 60 gal that puts out 11.5 cfm and while it keeps up it runs almost continuoulsy to do so if I'm using a die grinder for instance. The more it runs the more condensation you get which sucks, water dribbling out of your tool. My next one will be 80 gal, 18.5 cfm :thumbup:
 
To avoid the water in the tool problems I ran my line in 1 1/2 copper and after coming out of the compessor i ran the line up to ceiling and back down at the other end. At the turns I added about a 6"extension off the bottom with a water faucet valve and just open them up every once in awhile when in use to drain off any water. also added a water trap/regulator at the end.
Also if you plan on needing lot's of air, do not run your line with anything less than 1 inch line and use the larger air line hose. Also be careful on fitting selection since there are so many options. The quickest way to reduce a compressor's capability is to restrict it with line and fitting size. Also be carful with your regulator selection, they also have different cfm ratings.
I did alot of research about setting up for painting cars and such before installing my compressor and they all say the lines and fittings make or break the system, along with the overall line size.
 
EP87 said:
I checked my electrical service box last night and its got plenty of room for the bridged breakers for a 220v connection and is right next to were I plan on putting what ever compressor I end up with, and I've wired for 220v before
welder, dryer etc. so going with a 220v compressor shouldn't be a issue.
Click to expand...


Well make sure you run wiring to support a 40 Amp service and you should be ready for anything you get.
 
You must log in or register to reply here.
-

Back
Top