Steve Lovelock
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| posted on 10/1/11 at 10:29 PM |
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Air hose size
Hello,
I have been given a 3HP, 50Ltr, 14CFM compressor for Christmas and now need to get an air hose to go with it. I seem to remember that the longer the
hose the greater the pressure drop and I see that you can get lots of different sizes of internal bore. Does anybody have any recommendations for the
lenght and bore size I should select?
Cheers
Steve
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MakeEverything
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| posted on 10/1/11 at 10:41 PM |
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The 30m halfords one will do.
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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blakep82
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| posted on 10/1/11 at 10:52 PM |
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think mine's 8mm hose? 'had' a 10m long one (but i ran it over and it split), and got a 15m one. does me 
if you're using quick release connectors (as i'm sure you will) i can't see the point in going much bigger or smaller than the size
of the hole in the end of the connector.
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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hillbillyracer
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| posted on 10/1/11 at 11:17 PM |
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quote:
Originally posted by blakep82
think mine's 8mm hose? 'had' a 10m long one (but i ran it over and it split), and got a 15m one. does me
if you're using quick release connectors (as i'm sure you will) i can't see the point in going much bigger or smaller than the size
of the hole in the end of the connector.
The reason for going bigger than the connector diameter is to overcome the "wall drag" of the pipe, a long length of 6mm bore pipe will
suffer a massive pressure drop in comparison to a connector with a 6mm outlet.
We're fitting an airline into the workshop where I work & using 19mm bore to take it the lenth of 75ft long shed, but the outlet coupling
are just the 6mm ones.
For DIY in a household garage I would'nt think you'd really any bigger than 10mm bore, & 8mm would do most jobs if the line
is'nt too long but if you're going to use anything with an air motor (die grinder, air drill etc) it'll be a hungry thing,
especially an impact gun as it'll not perform as well.
Here's a chart giving sizes of pipe against distance & flow rate:
http://www.goodyearrubberproducts.com/files/Dixon/DixonCatalog/DixonCatalog1.Page531.asp
It's really for things on an industrial scale but it'll give you an idea of how it works out.
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blakep82
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| posted on 10/1/11 at 11:22 PM |
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^ ah well that explains it then thanks, when i've got some more cash i'll look at upgrading mine then.
i always thought you can move so much air through a 19mm hose, but the connector at the end will only slow it down, but i was wrong theres a lot
more science to it!
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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hillbillyracer
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| posted on 10/1/11 at 11:29 PM |
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Been looking into it a bit as we're doing the workshop, & I did'nt realise it made so much difference either! Took a bit to convince
the boss, hope it works better than the 10mm that was in when I get all connected! 
One hang-up the bigger you go I'm told is the water drops out of the air more & can puddle in the pipe, so you need to make sure on
permament lines that there are no low points unless they have a drain on them so you get rid of the water. On the upside that's another way of
getting more water out of the air which is a good thing, we'll know how inportant that is in a few weeks & see if the drain legs on the
line fill up.
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JoelP
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| posted on 11/1/11 at 11:26 AM |
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i think my 8mm hose was the limiting factor that made my air wrench crap, so id say 10mm is a better bet depending on length. A bloke off here came
round to help with his good air wrench, and it too was no good for the job at hand, so im fairly sure it was the hose.
I bought a crap cheap one recently because it was only really to blow tyres up (i have 22 tyres in regular use  )
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Peteff
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| posted on 11/1/11 at 02:39 PM |
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I have a 20' hose with a 3/8" bore and have no problems with pressure drop from my old SIP 3hp compressor. I bought a cheap rattle gun
from Aldi to undo a sprocket nut on the ZX9 engine and it ran it of no trouble. It also coped with the flywheel bolts on a Zetec 1800 which I had
chased round the shed with an extension and socket before I remembered I had an alternative 
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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