What to look for in an air compressor.

**Iwant1** · 19-04-2013

John could we get a bit more real life usage of the hydrovane 5 series.

I've been looking on ebay for some time now and they do come up often for around £300, which I don't mind paying, but when I read the specs of the 501, it only produces 4.2 cfm FAD. Seems crap against say a £300 secondhand 150ltr Sealey/Abac/Clarke with 14cfm. Would the 501 easily allow for some spray painting, blasting, sanding. Could it even be used for blowing chips away.

Feel like I have to look at a big 3 phase hydorvanes to get any where near descent Ccfm. But then these are a huge step up, with ratings of 20+ cfm.

Are the hydrovane and regular compressor cfm's not comparable?

Cheers Adil

**John S** · 19-04-2013

You have basically answerd your own question when you state 4.2cfm FAD which means Free Air delivery. because they don't have a swept volume like a piston compressor they have to state what they put out.

CFM means sod all, CFM is the swept volume x revs in one minute and doesn't take into account valves opening and closing which is when the proper work is done.

Read this.

The "power" of an air compressor

**m_c** · 19-04-2013

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**John S** · 19-04-2013

What you have to do with the tankless units is put them on a tank and run them up to see what pressure they spit out before they unload.

Then fit a pressure switch, machine mart are reasonable for these, and set it for 10 pounds less than the test pressure, this way they perform the same as the tank model.

**m_c** · 20-04-2013

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**AdCNC** · 20-04-2013

I had a 14cfm twin piston compressor and yes it could kick out 14cfm when the tank was full thats bout it. then i landed on a nearly new Abac 50+cfm jobby and that will do a proper continuous 50 cfm and its alot quieter than the old turd.

**John S** · 21-04-2013

Originally Posted by AdCNC

and its a lot quieter than the old turd.

Adam,
There is no need to get offensive, I can't help getting old................

**martin54** · 21-04-2013

I will have to look for another air compressor now, I have had an el cheapo model for years & it has been great for the things I was using it for, few air tools, bit of spraying, nail gun & blowing up the car tyres was about all it got used for.
Now I have built the blast cabinet it's just to small to handle the flow required at the correct pressure.
Still having read this thread at least I have a better idea what to look out for now.

**AdCNC** · 21-04-2013

Lol John how did you know i was talking about you :-p

**martin54** · 25-04-2013

Hope this isn't classed as a hijack it is about air compressors lol.

Read what John was saying about compressor outputs & that he had said to look out for hydrovane series 5 units but I'm not sure if something that size would do for the blast cabinet, the 5 series from what I can see chucks out about 5 cfm & the blast cabinet needs a minimum of 7 cfm @ 80 psi, more would be better.
Realise from Johns post that those figures might not mean a lot so needing a bit of help with what might be suitable without having to take out a loan.