Air hose

[diyhandyman]

Hi, i have 2 compressors, a 90ltr 3hp 14CFM, 9cfm FAD i'd say belt driven compressor, and a 1.5HP 50ltr compressor, probably 4.5CFM FAD. I got the two hooked together with 5mtrs of hose, it has 1/4" nuts on the end but the inner diameter is probably less than that. I use a recoil 50ft hose with 1/4" nuts, the yellow Clarke one from machine mart, which again probably has a tiny inner diameter.

The two compressors work pretty well together, i know it's kind of useless to have the 1.5HP one but it's better than nothing and it gives me an extra 50ltrs.

I want to operate spray guns from the system, and my problem is that the 50ft hose acts as a reservoir, and the volume of air that initially comes out the gun is a lot higher than a second or two later. I'm assuming that a bigger bore hose will solve this.

I want a 3/8" system, for 50ft of hose or so, (ideally would like 100ft but i don't think that it would work very well) and the problem is that the compressors have 1/4" outlets, and not 3/8". Would this significantly bottleneck my system? i just want a constant flow of air coming out my system of as much CFM as possible.

At the moment i have the 3hp compressor with the 1/4" 5m sealey hose going from the pressure switch of the compressor to the pressure switch of the 50ltr compressor. On the pressure switch of the 50ltr, i have a regulator which has a 1/4" outlet, with the 50ft recoil 1/4" hose to the spray gun. So my question is that can i just replace the 1/4" (outer diameter i guess) hoses with 3/8 inner diameter hoses and i will have constant flow coming out the 50ft 3/8" hose from the 50ltr compressor to my gun? Or do i have to have 3/8" fittings all the way, which would be a problem because the 3hp compressor has a 1/4" going to the pressure switch, welded on to the tank.

Thanks for reading, and any suggestions are very much appreciated.

 

[tigler]

The 1/4 outlets are a massive restriction, without changing those everything else is a waste of time.
The coupling hose between the compressors needs to be at least 1/2".
Feed to your gun needs to be at least 3/8".
The only thing 1/4" hose is good for is tyre inflation or blow guns.

 

[shenion]

1/4 hose is too restrictive.

The 1/4 outlets will be the biggest restriction but let them be the only one and it will help.

Most tanks have an inspection port. Make fittings and tie the tanks together with them with 1/2". Then use a better reg, the ones that come on compressors are crap.

I have 1/2" to my bench, then a 3/8" reg and 3/8 hose. I still use a 1/4 coupling and it works well enough.

All my hoses are 3/8".

On my spray guns I have a small reg fitted to the gun itself. I run 90PSI to the gun and adjust the final pressure at the gun. At 90 PSI, the 1/4 restriction upstream is not a problem.

 

[diyhandyman]

Ok I've taken some pictures of my compressor/fittings.
Here's the pressure switch inlet, it's a 1/4"

I think this is the inspection port you were talking about?

I've held a 3/8" thread next to it, so by the looks of it, it is a 1/2":

I don't think i have the tool to undo that stopper, it appears to be some sort of massive hex key?

 

[madkayaker]

If you can find a bolt with the right size head then you can use that to undo it

 

[Chipper]

Basically yes, replace the hose and if the fittings fit all's OK. 10mm hose will be fine. PCL fittings have the same bore anyway from 1/4" to 1/2" and flow plenty of air, about 40cfm @100psi I think.
http://www.draper.co.uk/catalogue/Pagesource/p601-605.pdf
Euro ones do differ in bore size.

If you don't need that full hose length it's worth not overdoing it to minimise friction losses.

Some of the topside ports are silly small like 2 of ours, best use the tank port as said. You'll want a water trap/regulator some distance away from the comp anyway (better chance for moisture drop out).

 

[brightspark]

Ok I've taken some pictures of my compressor/fittings.
Here's the pressure switch inlet, it's a 1/4"

I think this is the inspection port you were talking about?

I've held a 3/8" thread next to it, so by the looks of it, it is a 1/2":

I don't think i have the tool to undo that stopper, it appears to be some sort of massive hex key?

a pair of stillsons will undo the plug

 

[eil]

a pair of stillsons will undo the plug

Or even just one stillson.

 

[brightspark]

Or even just one stillson.

verry true but why does everything come in a pair when theres only one

 

[diyhandyman]

Ok i sheard the hell out of the one i wanted to take off, so that's stuffed, however i was lucky enough to find a second inspection port on the other end of the tank. I got that off and wow the hole is massive, it moves a LOT of air. I even decided to be a bit silly and mess it it under pressure and i undone it and the whole 90kg's or so rocketed forwards lol.

Ok so now I think i should just half inch it all? About the other 1.5hp 50ltr compressor, It's got a 3/8" port on it so i think that's enough and not worth messing with. I'll get a 1/2" or maybe even 3'4" pipe between the two compressors with a tee at the end of the inspection port, and have the other end of the tee going to a 1/2" pipe to a regulator/filter which will be quite some distance away, probably 50ft away. From the regulator/filter, ill have about 2 meters of 3/8" going to my gun. Hope it works out well. After seeing the type of flow from that inspection port, 1/4" seems like a kid.

Thanks for the help.

 

[eil]

Think about installing a ball valve or gate valve on the end of the receiver for when you don't really need a lot of air then you can close one or the other off, for things like blowing up tyres etc.