Tool Air compressor fill time sanity check

[DavidR8]

Hoping someone can give me a bit of a sanity check on my compressor fill time.
10.2 cfm @90 psi pump
40 gallon tank (2x20 joined)
8 minute fill time from empty.
2 minutes to refill from 90 psi to 125 psi.

Does this seem reasonable?

 

[jcdammeyer]

No idea. Never timed my Sears unit. I jump every time the big one starts up thought. Although I doubt that information helps...

 

[DavidR8]

No idea. Never timed my Sears unit. I jump every time the big one starts up thought. Although I doubt that information helps...

Yes, recall me jumping when yours started up!

 

[Tom Kitta]

CFM's your Air Compressor can Produce

Calculate the actual cfm's of your Air Compressor

www.spikevm.com

No, seems too slow.

 

[Proxule]

My 30 gallon takes about that from 120 or what ever to 160 cut off.

 

[whydontu]

quite reasonable.

Calculator at

High-Performance Screw Air Compressors for Industries

Online calculator to find out volume of air (CFM) of air compressor

www.bosscompressor.com

conversion calculators are at the bottom if the page. Also keep in mind temperature has a huge effect on air delivery, and so will humidity.

 

[Tom Kitta]

So this would mean that your compressor fills in faster from 90 psi to 125psi than from 0 to 90 psi - which is not exactly possible. I think you need to check your time again. Or your pressure gages are off. 6 min from 0 to 90 PSI would imply just over 50% of stated pump ability at 90 psi.

 

[Jswain]

Is the motor on it original? Spinning at the correct rpm? Belts tight enough to not slip?

~6cfm seems slightly low I'd expect more like 8-9cfm. Check the discharge tube from pump to check valve when it's cold with soapy water and the pump first kicks in to see if it's leaking at a connection.

 

[DavidR8]

Found a bunch of leaks. Fixing those took 30 seconds off the fill time.

A bit of fooling around bead blasting aluminum. Love the look of this.

 

[Tom O]

So how do you like the tabletop blaster is that with the aluminum oxide? I picked up some of the copper slag stuff to try out on mine I find the material doesn’t flow to the pickup tube very well.

 

[DavidR8]

So how do you like the tabletop blaster is that with the aluminum oxide? I picked up some of the copper slag stuff to try out on mine I find the material doesn’t flow to the pickup tube very well.

That was done with glass bead. Granules are about the size of salt.

https://www.princessauto.com/en/50-lb-greengrit-crushed-glass-blasting-abrasive/product/PA0008223794

I had to dry it out because it was quite damp and clumped something awful. Now that its dry it works very well.

 

[Tom O]

Ok I’ll try moving the pickup tomorrow and take some media out it says 10 lbs max and I put in around 25 ( half bag )

 

[CWret]

25+ years ago I had a shop and lived beside Kelso Conversation Area. I owned several large compressors for my drilling business (300 to 425 Hp). The Kelso snow making equipment (for the ski hill) was 150psi. After doing modifications to their air lines (lots of 2” to 6” piping), they had to test it to over 200psi but their compressors were limited to 175psi. As a good neighbour, I often let them borrow my 750cfm/300psi compressor to pressure test their pipes. I was surprised at how much fuel was required. It took over 3 hours with the 750 compressor running full-out to pressure test their system.

 

[Alexander]

David what make and model is your compressor? Some of the companies like Colman and husky exaggerate the cfm of their pumps. Even really good companies do that too.I measured my atlas copco and it wasn't getting to the advertised CFM. In that case I might have been under driving the pump.

 

[DavidR8]

@Alexander it is a Husky pump and motor so there is that

 

[Alexander]

Yeah i was wondering based on your results. There might be nothing wrong with it. They just overstated the CFM in there marketing materials

 

[Jswain]

30 secs is a good improvement! Love taking parts out of the blasting cabinet

 

[DavidR8]

Yeah i was wondering based on your results. There might be nothing wrong with it. They just overstated the CFM in there marketing materials

In truth, the additional 20 gallons of air makes a huge difference when using my benchtop blasting cabinet. Overall I'm quite happy with the setup.
I have a total of $475 into it.
I'll sell the two original Speedaire pumps and motors so my total investment may end up $250 range.

 

[DavidR8]

Separated the two tanks this afternoon. Checked belt tension.
Turns out the belt was loose, likely because it was brand new so has worn in.
Cut the 0-60 psi time in more than half; 3 mins vs 1:22.
Time to 125 psi is now 3:22 on a single tank.
That’s a massive improvement.

 

[Jswain]

Double the CFM for free