What is considered the minimum? What is optimal? ( for a compressor )

How many gallon tank
PSI
CFM

Thanks guys.

 

It really depends on what the use will be for.......pneumatic tools will have a minimum spec stated for their use................

 

125 psi for pressure feed and @ 20CFM to stay with 1/8 tip

I run 80 gal 7.5 HP Ingersoll Rand 175 psi two stage with a 2HP General make up compressor.

 

Minimum would be a single stage 30 gallon, and works for small parts or small areas at about 90psi. 60 gallons would get you a little more work before down time, but either would need time to refill. I use my 30 (5.1 SCFM @ 90psi) for small parts and it isn't bad. Large areas take awhile because it has to refill the tank. A two stage 60 or higher would be ideal, and in this scenario, bigger is better. I would say 10 SCFM to even 15 SCFM would be ideal, rated at 90psi.

I didn't have the money or the 230v required so i went with the 30gal. If I did it over, I'd get the 60 gallon two stage and wire it in. I have the 230v now and I will in get the 60 in the future, so I don't care if I burn up my 30.

 

Thanks guys.
Another Question: When looking at used compressors what are common problem areas or issues I should be aware of?

 

I wish I had an answer to this one. Compressors, or at least the tanks, tend to rust from the inside out and I do not think there is a way to be sure it's rotten until it leaks. I empty mine and keep it empty when not in use. The valve releases water that it in the air and accumulates inside the tank. Makes me wonder if there is a way to filter the air as it comes in, preventing water from ever even getting in, but I doubt it.

 

Yeah, considering hydrogens affinity for oxygen probably not.

Anyone else have any tips?

 

Hey RIPbiker13, To answer your question, I just did a little research and they do have filter sys. to take the moisture out. If you do a little searching you can probably find out what will work for your set up. Cheers, Todd.

 

It would be nice if it was running so you can hear and see how long it take to buildup pressure.
Once it has psi in the tank open the drain, even if no psi and see what comes out. Some water is ok a lot of water not ok as they may not have drained it often and rust could be on the bottom. Look at the color of the water, clear is ok but rust color not so good.

Also note if what comes out is oil, not good but can have a reason why. Dirty intake filters can be a cause of oil in the tank are they clean?
If they are clean then maybe the rings are bad?

Like a car / truck what shape is the out side of the unit? Clean they may have taken care of it dirty then maybe not?

I got my compressor off Ebay for under $1000 It is a Snap On big red can from a 5 bay truck shop. Said pump was rebuilt and electric motor new and it looked it from pictures.
When I went to run it found the head was loose so I replaced the head gaskets and valves, pistons & walls looked good.
Also found the motor starter was welded closed because the tank to pump check valve was bad.
So for about $30 bucks in parts I had a real nice compressor.


Google DIY compressed air drier or cooler should come up with a few hits.

There is a way to lessen the amount of water getting into the tank. When the air is compressed it heats up, when it cools off in the tank is when the water falls out of the air and sits on the bottom.
Thing is how to cool that air before the tank? Run it thru a cooler. Some have used car AC condensers. From pump to the condensers to cool the air to a small tank to catch the water then into the big tank. The small tank can have an auto drain or just drain it often.

Others just go pump to big tank then out to a cooler with drip legs to catch the water before being used.
This is the type I use and U also have drip legs at each hose drop that I have 5 of. It was easy to make and was made for use in a smaller garage I had back then I now use it in a much larger garage.
Air drier - hot air comes in on the bottom left up n down and out on the right about half way down. Drip legs to catch water at the bottom.

Here it is with compressor in my larger garage and you can see 1of the hose drop to the right of the cooler.

Dave ----

 

Thanks Dave for the pics. I hope I can ask you some questions when I get the stuff.

 

Dave, is that a Gremlin? Looks like a early one. I had one. A 77' with a I6 and 4 speed. Fire engine red with white stripes. I could take most of my buddies for the first 2 hundred yards or so? LMAO. Good times.

Corvette or Camaro hood? Probably neither.

 

$140 Deal / No Deal? We ran it at the guys shop for 20 minutes up to 125psi. Ran good. Drained clear. Guy has two REAL compressors. Said he got this one from a guy who couldn't pay his bill.

 

Sorry for getting back so late.
Yes it is a Gremlin It's a 75, sitting down, a factory V8 / auto car with a 2.87 rear gear so a dog off the line but will do 90 MPH in 2nd gear.
It has a Holley 2v carb replacing the Motorcraft 2150 on the stock 2v intake. A shift kit on the TF999 and will chirp tires going into 2nd and that is with a Lock Right locker out back.
The carb, shift kit & locker were for 1/4mile track but did not want to do more as I was building a drag car.

But you were wrong on the GM hood. It is a 1 year only 1970 AMC Javelin skin. If you can find a hood they start at $1000 and up. The skin will fit a base model hood frame when I find one.
I have 2 70 Javelins one is a street car with that 1 year hood the other my drag car with a base hood & 6pk hood scoop.

For that money I think I would of gone for it if it was better than what I had.
When looking at compressors you need to know what the max CFM tool you are going to use is and at what PSI. Then you want to add a little more or a lot to the CFM and that it what you want for your compressor.
So if that tool uses say 10 CFM @ 50 PSI you would want your compressor to make more CFM or the compressor will be running nonstop and that is not good for the unit.
(edit) I did see a CFM rating in the first picture for that compressor but it dose not make it bad for a home garage depending on what you need to do.
Just something to keep in mind when looking for one.

If you need information sooner, I don't get over here too often, PM me and I will answer.
Dave ----