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View Full Version : Air Compressor size.


Steve Webb
27-08-12, 19:38
The time has come that having an impact gun around the place would come in handy and make jobs easier.
Now I've got a small compressor, but just how much air do these tools use? What are your experiences?

Cheers
AlfaJack
27-08-12, 20:29
All I would say is get much bigger than you need.

The CFM needs to be calculated with a loss of one 1/3 to know the Free Air delivery.

You have 3 phase to the house don't you - aim big - 14CFM will cut it for airtools but by the time you want to do the odd bit of sand blasting at home and then spraying your car and using an airfed mask you will want an 18CFM.
wrinx
30-08-12, 09:50
I've got a large compressor which won't run impact guns and struggles with a cut off grinder...but we're limited on the power by 240 electrics.

I'll post the specs in a few days.

wrinx
AlfaJack
30-08-12, 09:53
I've got a large compressor which won't run impact guns and struggles with a cut off grinder...but we're limited on the power by 240 electrics.

I'll post the specs in a few days.

wrinx

Good point. Our 14CFM runs out of puff with the air grinder quite quickly.
Steve Webb
30-08-12, 21:34
An 18cfm compressor looks like its going to be pretty expensive! So looking at the problem in a different way, what are electric impact wrenches like?
wrinx
31-08-12, 08:19
I've got a cheapy cordless impact driver which has saved me on a couple of occassions with hub nuts, but they're too unwieldy imho for general use.

From memory my compressor has a 200 litre capacity with a 3hp motor but will check...

wrinx
AlfaJack
31-08-12, 09:19
From memory my compressor has a 200 litre capacity with a 3hp motor but will check...

wrinx

Sounds about right for single 240v :)

You could get two 3hps and plumb them together :D
Steve Webb
01-09-12, 08:03
I've got a cheapy cordless impact driver which has saved me on a couple of occassions with hub nuts, but they're too unwieldy imho for general use.

I think I'll go down this route for the moment, its hub nuts and the like that are causing me problems.
wrinx
01-09-12, 16:42
Buy the most powerful one you can afford, Mine was a gift so not sure on the exact price but it would have been less the a hundred pounds...it's probably mid range on power but has used both batteries to shift some obstinate nuts.

Buy one with two batteries or a quick charger.

wrinx
wrinx
01-09-12, 16:45
This is more or less the same as mine although it didn't cost this much when I bought it! Neither did it come with the accessory kit or handle :roll:

http://www.sipuk.co.uk/tools/info_SIP04294.html

So 13-14cfm, I thought that would be enough to run most air tools, but no :(

Edit: Mine is the 150L version, not 200L, but the other specs are similar at 14cfm and 8.6cfm of free air.

wrinx
1NRO
02-09-12, 09:52
Having had a few compressors over the years and had to listen to them all and cuss them when they run out of puff the next one I get will be something along these lines albeit a bit more keenly priced, they come up on ebay all the time for decent money. Don't think I'd ever max that kind of output and quiet too.
http://www.ebay.co.uk/itm/BOGE-S15-screw-air-compressor-2003-quiet-/160876036146?pt=UK_Air_Tools_and_Compressors&hash=item2574f58032
Steve Webb
02-09-12, 16:05
Thats quite a lot of puff.

I've just been looking around the classified ads over here and spotted this one not too far away,

500L tank and 5.5kw (7hp) tri-phase motor

http://www.leboncoin.fr/materiel_professionnel/350804454.htm?ca=2_s

Mind you I'd need to built a small shed for it to live in.
Finn
01-10-12, 13:54
My compressor died for the third time in two years so have decided on a whim to get a new one. But having read through this I'm not so sure if it'll be powerful enough. It's a 3 phase, 4hp motor with 200l tank and 16,9 cfm. The next in the model range was a lot more expensive (about €500 more), but now I'm thinking I maybe should've gone for that one.
AlfaJack
01-10-12, 16:28
My compressor died for the third time in two years so have decided on a whim to get a new one. But having read through this I'm not so sure if it'll be powerful enough. It's a 3 phase, 4hp motor with 200l tank and 16,9 cfm. The next in the model range was a lot more expensive (about €500 more), but now I'm thinking I maybe should've gone for that one.

That is pretty good!
What do you want to use it for?
Steve Webb
01-10-12, 18:35
I think you'll be fine with that one Finn.

As soon as you buy one there is always going to be what you think is a better one come along. You could go on for ever until you end up with one that is far too powerful for your day to day needs.
Finn
02-10-12, 06:57
I think it'll be fine. It certainly is better than the old one which had 1 phase motor with 150l tank. I use it for airtools (impact gun, cutters, "dremeltool", paintgun and blastcabinet). Can't wait to have it delivered. In the meanwhile I use an old mini compressor (24l tank) which is a real pain as it runs out of puff the whole time - one bolt off and wait 2 min. until its full again...
Steve Webb
05-10-12, 22:42
Has it arrived yet?

I think its time to turn this into a 'show us your compressor' thread.
Finn
09-11-12, 09:57
We went to get it last friday. It's a huge improvement over the last one, even though this one also runs out of puff quite fast and it is quite loud.

http://farm8.staticflickr.com/7253/8150974056_75b08a825a_z.jpg