Pressure when using air tools

[M@tt]

I've recently bought a 150l 14cfm air compressor which i'm using to run a couple of airtools in my shed, however i'm having a bit of a problem with the air pressure i think. It appears to be working fine in that it doesn't leak and it fills the tank fairly quickly.

However even with the pressure valve turned to max so its reading well over 100psi on the compressor and with the tool connected directly to the compressor, when i'm actually running the tool the pressure drops right down really quickly to about 2 bar and the tool really struggles to work (90 degree die sander, air ratchet etc) I have to use the tool in really quick sharp bursts so that the pressure is high enough at the tool.

Any ideas what i might be doing wrong?

 

[Iain Westland]

does it auto kick in or do you manually have to turn it on? ours re-starts at about 80psi and shuts at 130psi, a reg on the out let might help too, some tools like a max input so you might be wasting air

 

[gordon stephenson]

Check that the pressure reg is capable of passing the volume of air the tool requires, Also what bore and length of hose are you using, I prefer a 10mm bore with just a short 6foot whip of smaller dia conected to the tool.

 

[M@tt]

no it kicks in every now and again after using it for a period and i'm pretty sure it does exactly as yours does ie cuts in about 80 and off at about 130

i do have a regulator/water trap/oiler which the airtool were connected to but i wasn't sure if the problem was with that hence tryinging to connect the tools directly to the compressor, but it made no difference.

the air tools say max pressure 90psi on them

 

[M@tt]

the regulator is the standard one that came with the compressor as far as i'm aware and the specs of the compressor are 14cfm so i would assume it should be able to handle it, does that sound about right?

i'm using 8mm ID hose with a 10m hose, could it be the hose is too long and ID too small?

 

[rtbcomp]

.....i'm using 8mm ID hose with a 10m hose, could it be the hose is too long and ID too small?

Try knocking up a very short hose and see if the situation improves. 10m is a long length and most people use 10mm ID.

You'd be better off installing copper or steel pipes to various points in the workshop and running short flexibles to where you're working.

Also run the pipework at tank pressure and put the regulator nearer to where you're working.

Look here for some ideas http://www.mig-welding.co.uk/spray-painting.htm

 

[Luke]

the regulator supplied with my compressor was absolute rubbish, and wouldn't pass the volume of air that tools required.

What regulator do you have, and does it have a reduced orifice fitted?

 

[M@tt]

This is the comprssor a SIP airstream 150l 3hp

The way i have it set up is i have about 1.5m of 8mm ID hose from the tank to the to a wall mounted water trap/regulator/oiler. I've got brand new quick connectors at both ends so that i can unplug the jooining hose if nesessary.

I have another quick connector on the outlet of the wall mounted regulator and i attach my 10m hose and air tools to that.

I'm using these 1/4" BSP PCL style connectors so that the hose can be removed and tidied away when not in use.

The wall mounted regulator gauge is reading more or less the same as the tank pressure gauge so there doesn't appear to be a drop between the 2 there.

Cheers for the replies so far

 

[M@tt]

i've not had chance to get a 10mm 3/8 ID hose yet bet heres a few vids of what is happeining

1st vid, die grinder connected direct to wall mounted pressure regulator from compressor by 1.5m 8mm id hose. Regulator set to MAX


2nd vid, die grinder connected direct to wall mounted pressure regulator and regulator pressure set to ~80psi

this goes a bit weird in that with the trigger completely pulled the pressure rises initally then falls off!


die grinder connected via shorp 8mm whip to compressor with a pressure regulator attached


how do people who use these all the time have the presure set?

 

[eil]

quite a pressure drop there, id say you needed a 1/2" connector from your tank to your regulator otherwise you would have to add that pressure drop to your receiver pressure for it to work.

 

[M@tt]

yeah but what is confusing me is as far as i can tell most commercial places( garages etc) use these 1/4" PCL connectors and don't appear to have any of these problems. And i'm connecting the tool pretty much direct to the tank but still experiencing the problem.

bit stumped and bit reluctnt to spend £30 on a 3/8" 10mm ID hose only to find i've still got the same problem.

any ideas?

 

[eil]

Yes from the reg to the tool but they will have at least a half inch pipe feeding from tank to the regulator as well as having their compressors going up to 150psi or higher.

 

[M@tt]

cheers for the reply eil

i think i get it but i'm just a bit stumped that even connecting the tool with a short whip lead direct to the compressor i'm still getting such a massive pressure drop. I guess the 8mm ID is just too small a hose regardless of length for air tools.

I guess the only thing to do is to try a short 1/2" ID hose from compressor direct to tool and see if that works? i presume i can still get the appropriate PCL connectors in 1/2" size

****** more expense

 

[eil]

I must have misunderstood you, you say you have connected straight from receiver to the tool without going through the regulator and it still doesn't work ?

 

[M@tt]

yeah on the thrid vid i connected the short 8mm ID whip hose from the die grinder straight to the regulator on the compressor tank with it wound up to max and i still get a pressure drop on the tank regulator from 130psi to about 20 psi when i pull the trigger

 

[eil]

Got it, you still have it going through the regulator then, what size is the inlet to the regulator from the tank?. as has been said the regulators that come with some compressors are quite restrictive.

 

[M@tt]

it's got quite a large connector into the tank itself (1/2" maybe?) but the outlet after the gauge is 1/4" so i guess i could do away with the on tank regulator and have a 1/2" hose straight from the tank to the on wall regulator

nothing is ever staright forward is it

 

[eil]

This made a hell of a difference to mine as is the case with a lot of guys on here.

 

[M@tt]

brilliant cheers

i take it the regulator/water trap also has 1/2" inlet outlet connectors on it otherwise i'd guess i'd be introducing a restriction into it by using one with 1/4" connectors

oh also are these "high flow" 5/8 connectors better to use than the longer thinner ones?

ie

vs

or will it not matter?

 

[Gasman]

yeah on the thrid vid i connected the short 8mm ID whip hose from the die grinder straight to the regulator on the compressor tank with it wound up to max and i still get a pressure drop on the tank regulator from 130psi to about 20 psi when i pull the trigger

This doesn't sound right at all IMHO.

If the compressor has been running and has a full tank and this drop happens instantly with a tool connected you may have a flow issue caused by a faulty regulator. I'd double check the regulator settings.

The ideal set-up (as used in garage workshops etc) is to have a 1/2 bsp hose directly from the receiver onto a wall reg/trap and then piped to outlets which drop to 1/4 PCL like you have there. This would be a bit OTT for home use. Check the reg!!