I saw a thread earlier....

[rtbcomp]

Of course the ideal solution is to house it outside in it's own seperate enclosure with louvre doors for cooling and maybe even an extractor fan.

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Mine is in an outside enclosure, but louvres let the noise out and my workshop is in a residential area. I've lined the housing with insulation and put a thick layer of sand on the floor to try to absorb some of the noise.

Most of the noise comes out of the intake, extending mine made this worse, I'll modify it eventually to be like a motor car silencer, for the time being I've buried the end in a pile of cushions!

 

[rtbcomp]

Can you point me to the clarke regulator on the machine mart site? Is it this one? http://www.machinemart.co.uk/shop/p...path/air-line-equipment-air-hose/brand/clarke

That only has 12 bar inlet and 6 bar outlet, about 85psi according to the website, but 13/12 bar according to the catalogue

That messes me about a bit as I'm after a new regulator too and was looking at the same unit.

 

[Lippyp]

I have no near neighbours (well on a sunday I do but they'll never hear it over the organ! benefits of living in a former manse, with a council community centre type building the other side) At least if the intake is outside it'll not deafen you in the workshop. I wonder if an el-cheapo glass pack type silencer would work to quieten it down without being too restrictive?

 

[BillJ]

I know a lot of guys in the USA who actually route an air intake through the garage wall with something like a K&N air filter on the end

Not only in the USA and an outside supply is essential if you're running an air-fed mask from the compressor, otherwise you're feeding the mask with the poisonous air you're trying to avoid breathing.

Can you point me to the clarke regulator on the machine mart site? Is it this one? http://www.machinemart.co.uk/shop/p...path/air-line-equipment-air-hose/brand/clarke

Yes, that's the one I linked to earlier. If it manages half the 42cfm it claims, it certainly won't be the bottleneck in my setup.

Regarding airflow rate, one of the advantages of a bigger receiver is surely that as long as you have a big enough outlet from the receiver, via a big enough regulator and big enough hose, you can get much more airflow in short bursts than the compressor can provide. Not as good as a more powerful compressor, obviously, since you will have to stop regularly to let the compressor catch up, but it does allow you to do things that otherwise would require a bigger compressor that you might not be able to run from your power supply.

 

[rtbcomp]

Regarding airflow rate, one of the advantages of a bigger receiver is surely that as long as you have a big enough outlet from the receiver, via a big enough regulator and big enough hose, you can get much more airflow in short bursts than the compressor can provide. Not as good as a more powerful compressor, obviously, since you will have to stop regularly to let the compressor catch up, but it does allow you to do things that otherwise would require a bigger compressor that you might not be able to run from your power supply.

True enough, but it can easily double the time taken to do a job. Would you be better with 10 cfm and 150 litres or 12 cfm and 100 litres when you need 14 cfm in small bursts

If you have a fixed budget I'd still go for the bigger cfm.

 

[BillJ]

I agree absolutely. However, sooner or later you run into one constraint or another in choosing a suitable compressor. In my case it was the restriction to 3hp imposed by the fact that I need it to run from a 13A socket. Luckily, I don't tend to need a huge airflow over a long period so a 3hp compressor with 150 litre tank works for me. Everything's a compromise.

 

[rtbcomp]

Depending how your building's wired you could have 2 3hp compressors on seperate ring mains.

 

[BillJ]

There come into play two more constraints: a 16A circuit and a lack of space
It's fine for what I use it for. On the odd occasion when I need a hefty airflow for a short while, the large tank can cope.

 

[MrFluffy]

Ill chime in late with the high cfm small tank crowd. I am spoiled though now after years of drinking too much tea waiting for compressors to fill their (oversized for the sales spec sheet) tanks, I went out and sourced once and for all a monster 3 phase compressor for my workshop, then another just popped up when I least expected, and at a price that it'd be rude not to. So now one for the workshop and one for the garage cos burying 20M of hard airline under the garden between the two sounded like a recipe for disaster over the years.
Garage one is having purpose built enclosure to keep the weather off it (noise isnt a issue, the local cows dont mind) so it can breath clean air to feed a airfed mask and so it doesnt encroach on floorspace.
Both are 70cfm and 500L tanks, but I need to use the pallet truck to move them.

When I look on ebay, theres usually a few big old belt driven monsters, usually theyre ok, although if your really unlucky they'll have a bad bore on the high pressure cylinder or something but thats worst case scenario. Theyre certainly a lot more compressor for the money than buying a shiney one in machine mart. When I had 240 only, I bought a belt driven one and changed the motor for a single phase unit and used a smaller pulley, not as quick to build up but needs must. I still have it and it still works, but Im considering swapping the electric motor for a petrol lump and using the nema to control a aircon clutch on the output shaft of the engine. We have the technology to rebuild it

Years ago I bought a wind up hose reel from these people and its been a godsend over the years, it lives bolted the wall permanently and means the airline is always put away cos its a doddle to reel back, and you can lace it with large bore hosing and schrader connectors instead of them qd ones that dont flow enough :-
http://www.northerntooluk.com/products.asp?partno=159184E

Best stop rambling now, but, tools , mmmm, I have a bad tool habit..

 

[rtbcomp]

Both are 70cfm and 500L tanks, Heaven !!!

As an alternative to an air clutch you can get a valve that will dump the compressor output to atmosphere when the set pressure is reached. These are sometimes used where a compressor has a high duty cycle to cool the cylinders by working them at zero pressure.

 

[MrFluffy]

Is that how the commercial petrol welders are done?
I just came up with the aircon clutch idea whilst musing it over the other day, since a) I have a aircon unit I can pillage for the clutch, and b) it was the only way I could think of to do it...

 

[rtbcomp]

Is that how the commercial petrol welders are done?
I just came up with the aircon clutch idea whilst musing it over the other day, since a) I have a aircon unit I can pillage for the clutch, and b) it was the only way I could think of to do it...

I've only seen one on an electric machine that the guy ran continuously when spraying. He had it set up so the motor switch cut out before the valve opened, so if he wanted to operate using the valve he closed a switch that shorted the pressure switch.

Make sure you've got a suitable safety valve fitted!

 

[Welderpaul]

I've been through this with my SIP compressor - 3hp, 150 litre.
Performance of the tools was pathetic and I didn't know why as I'd never owned a compressor before. I got a clue when I saw the pressure at the regulator dip really low every time I pressed the trigger on the grit-blaster. The tank had 150 litres of air in it at 8 bar and couldn't maintain any real flow at 6 bar from the regulator.

The receiver had a 1/2" fitting but the tiny SIP toy regulator had a 1/4" fitting via an adapter. When I dismantled the regulator, I really couldn't see how any volume of air at all could get through it.

I chucked the original regulator and bought a Clarke one from Machine Mart that had a 1/2" fitting and was specced at some enormous flow rate.

Problem solved

Cheers Bill J, that seems to have solved the problem, I must admit I would have been suprised that SIP would knowingly stiffle the performance of a 9 bar compressor by fitting a regulator that gives out less power than some of my farts! - But it would appear they do. Before purchasing a new reg I ran a 1/2 inch pipe straight from the tank to a quick coupling (Yes I know! - I will fit a reg) and suprise suprise it kicked out the full 9 bar!

 

[Leanne1979]

Hmmm
I gave my compressor a try at the weekend with the air tools that i bought (2hp 50L) and it seemed fine, the only tool i would say it struggled on was the die grinder. but the other seemed ok, I mean the compressor kicked in after a few minutes but it still kept up with the demand
Leanne

 

[andyF]

hmmm, so I've just been looking at the thread about the 1/2 and 1/4 fittings and adaptors, now it could well be I'm a bit thick today but I've just been looking in the Clarke Catologue and yes you get the 1/2 with 1/2 outlet but surely the connector at the tool is 1/4 so isn't that just restricting the flow of air further on down the line or is it what happeens at the rgulator the important thing?


Andy

 

[BillJ]

That's great, Paul. Glad it sorted you out.
Yes, I was surprised too but after some experimentation, it was the only thing I could think of that might be the cause.

So, add £20 for a decent regulator and the SIP is still pretty good value for money.

Now if only I could upgrade the wire feed on my Migmate 130 for £20...

 

[drivewasher]

I went through this last year, the reason compressors don't stand up to the book specs is the manufacturers misslead you!
When they quote a machine's cfm IE 12cfm thats it's intake, when the piston(s) have done there job and compressed the air it comes out at less cfm. (i think the figures were about 20-25% less. So our 12 cfm becomes 8cfm.
This 8cfm is refered to as ACTUALL CUBIC FEET/MIN (acfm).
So when buying a compressor it's the acfm that matters this is the figure to match to tool. A tool thats the specs say demands 8 cfm is 8acfm so this would need a 12cfm compressor
I have a Fiac compressor that is 10acfm but is rated on the data plate as 14cfm

 

[rtbcomp]

I went through this last year, the reason compressors don't stand up to the book specs is the manufacturers misslead you!
When they quote a machine's cfm IE 12cfm thats it's intake, when the piston(s) have done there job and compressed the air it comes out at less cfm. (i think the figures were about 20-25% less. So our 12 cfm becomes 8cfm.
This 8cfm is refered to as ACTUALL CUBIC FEET/MIN (acfm).
So when buying a compressor it's the acfm that matters this is the figure to match to tool. A tool thats the specs say demands 8 cfm is 8acfm so this would need a 12cfm compressor
I have a Fiac compressor that is 10acfm but is rated on the data plate as 14cfm

The difference between cfm and acfm will depend on the pressure and temperature. The mass of air will remain the same.

(p1 * v1)/T1 = (p2 * v2)/T2 (T = temperature in degrees absolute)

What's fad (free air displacement) ?

 

[Luke]

Cheap compressors are fitted with a restrictive valve to try to keep them within their duty cycle, i believe.

My Clarke compressor came with a crappy reg and a little needle-valve cut off valve type thing. the orifice through this was maybe 2mm dia at best. It was absolutely crap.

I removed the reg and valve, and fitted an external reg and water seperator, oh and a 300L air tank....

 

[Welderpaul]

Aye, i've sort of come to that conclusion. Mines a huge SIP thing that looks and sounds like it should be a beast. But in reality it's just a pile of crap.
Sip crap.