Air compressor advice

[squirrelciv]

Guys, I'd like to tap into the collective knowledge if I may.

I'm thinking of buying a small(ish) compressor for the shed, but what size/capacity?

Will need to be electric and I'd like to be able to use it for spray painting as well as running power tools.


Cheers guys

[guest40]

Ideal: min 15 cfm, belt drive, twin cylinder and 40 litres plus. anything less will disappoint if using a ratchet gun or sander/grinder. Never use more than 90psi on any airtool, except blow off guns and nailguns. Desoutter wont cover warranty if used over 110psi. Beware of ridiculous claims of higher pressures

Never get Pressure and Flow confused. I have had "Engineers" ask for 90 psi regs. When asked what size, the answer was 90 psi! "What are you stupid didn't you hear me, 90 psi?".. Errr I/8" or 1/2" or 1".......?  I/4 is usually adequate
 
If at all possible steer away from the Chinese 2.5 HP. You cannot get parts. They are cheap and nasty. Try to get a good S/H unit at liquidation auctions. I have an Italian 1.5 HP/ 25 litre 10 cfm unit for blowdowns and a new hardly used 2.5 HP 12 cfm 40 litre piece of chinese crap. We learn by our errors. I bought the Chinese unit to extend the overall volume to be able to run the airgun/ ratchet for more than 10 seconds and can attach the italian unit to the main tank giving me 60 litres of air.
ALWAYS run with filter 40 micron or finer. If painting use .01 micron after a 5 micron. Contrary to popular belief filters are not moisture removers and only drain off condensate. You can only dry air by lowering the dewpoint by refrigeration, or with chemical adsorption driers.

Always use a lubricator with air tools. I run two lines, one only regulated for blowing up tyres and blowing down stuff and one with FRL.for the tools. If you paint, you dont want to use airline with oil or water in it.


Airtools: Best you can afford, within reason based on usage.
top brand: Desoutter. (Industial quality)
Home garage: Automotive quality is good enough.
I actually only use the cheaper tools as I dont use them enough to warrant big bikkies, and can replace them many times over and I havent worn anything out yet.
Compressed air is much more expensive to use than electricity, so make sure all your joints and fittings are tight and don't waste it with leaks.
I worked for Norgren for 12 years and Bosch pnuematics for 4years. I've forgotten most of it..

 

[squirrelciv]

Great response Kurt, cheers matey. 

One question....

What does cfm stand for??

[guest40]

Cubic feet per minute. It relates to the flow. If an airtool uses 9cfm it will drain a 25liter tank in 2.5 minutes approx but only useable pressure for about 1 minute. Your compressor must be able to keep up to the drain for continuous use, but in fact it should be able to pump more air otherwise it will run continuously. When you buy tools etc the manufacturers  may list CFM or L/min its roughly 30 litres per min to 1 cubic foot.  Pnuematics have many variables so its always preferable to have more than adequate for your needs.
Unlike electric motors there is no danger of a burnout if the motor is stalled.
You will probably want a rattle gun, blow gun, painting equipment, ratchet and engine cleaning gun and tyre inflator.
 You may also want an angle grinder ,drill and screwdriver, but it is more economical to use electric/cordless electric. Dont forget the airhose. it is heavier and more of a drag than electric cables.
If you have plenty of money you may also want nibblers and shears.
It is imperative to use the correct oils for the compressor as for the airtools themselves. Remember to keep paint lines aside and free of oiled air.

If you have kids, keep them away from it. It can be very dangerous.

Oh yeah, if you use airtools in very cold situations, the moisture in the air can freeze..this ice can cause the tool to rust very quickly if you leave it without cleaning the water out and ....if you use die grinders keep your fingers away from the outlet as you may find your digit frozen to the metal housing.

[guest7]

My mate did have a large compressor tank that he wanted to give away, would just need some fittings and a pump.

[squirrelciv]

Nice offer GC, but I don't know enough about the things to fit up all the rest of the gubbins. Best I buy one complete, but thanks anyway.

[johnr]

ive one of the aldi compressors, its ok for what i use it for, and ive had it 5 years now with no bother from it!

[guest40]

If anyone wants a handlebar mounted pnuematic gear shift for the bike I can tell them how to set it up. I assisted in the design for a Quadraplegic friend who raced of all things quads.
It is a lightning fast change too.