Size of air hose

If your spraying i would go for the larger hose

about the internal diameter? I've always used 3/8" ID but 1/4" is somewhat cheaper and maybe as good, for my purposes anyway. The length is 10 metres and I guess that 1/4" would do, even for a bit of car body spraying.

rubber, which I've always used and which perishes after a few years?

I use 3/8. pressure does drop over the length so depends what your using it for.

1/4 ore should be fine but you will get a pressure drop of about 1lb per foot on 1/4 inch bore, so at 10 metres you would lose about 30lbs of pressure, you'd have to wack up the pressure valve by 30lbs to compensate for the pressure drop.

airflow rate that is important.

Bore dia or length of hose has no affect on the pressure at the end of the hose but does have a considerable affect on flow rate which is the important factor for most air tools.

Upping the pressure will increase the flow rate, or CFM delivery, but you wont get a consistant air flow unless the rating of the compressor is equal to, or above that required by the spraygun or air tool being used.

A bigger hose is usually better for most air tools. Personally I'de go for the bigger hose size as it's likely to be more useful for air tools apart from just a spray gun. Mike.

The smaller the bore the greater the pressure drop at any particular flow rate, the longer the hose the greater the pressure drop at any particular flow rate, they're related.

For static pressure that would be true.

ing about the internal diameter? I've always used 3/8" ID but 1/4" is somew= hat cheaper and maybe as good, for my purposes anyway. The length is 10 met= res and I guess that 1/4" would do, even for a bit of car body spraying.

with rubber, which I've always used and which perishes after a few years?

OK, I think I'll stick with 3/8", which is what I've always used. What abou= t PVC v rubber?

rubber. PVC goes stiff and awkward and then splits with a big bang. The heavy half inch bore rubber hose that I use for everything (tool wise) has now lasted thirty years without failing, pretty tiring to spray with, but I use a short lighter whip hose for anything other than little jobs, just the last 2 metres is enough to keep it less tiring and more waggleable.

I found a 20m length of wire reinforced twin wall rubber air hose at a bootsale a few years ago and was glad to get it - it's indestructible. Like you, I use a plastic whip hose at the business end and it's fine.