Compressor

[Colin Blackburn]

I need to get a compressor to clear a borehole of particulate build-up. Since I'm getting one I thought I could make use of it for other jobs, initially spray-painting large surfaces, probably pumping up the car's tyres and later nailing.

Are all the various compressors and tools compatible? Or do I need to look for specific connectors to avoid lots of adaptors?

If a compressor is rated at a particular pressure I assume that is the maximum and any tool which uses less than that will work, is this right? How about the reservoir, I saw one tool listed as requiring a 24 litre reservoir, what effect could this have on tool function?

What about brands? Is Wolf okay? How about the lower price end, would a

99 quid compressor:

any good as a general low usage tool driver?

Any general guidance to using small compressors would be most appreciated.

Colin

[Dave Plowman]

Pretty well any tiny compressor can give high pressures - a cheap electric car battery operated one for example.

The important thing is the air flow, not maximum pressure. This is measured in CFM, or cubic feet per minute. If using air tools with it you need to check it will supply what's needed, and they all vary. A tank will make up short term inadequacies, but will be a pain if you are forever having to stop what you're doing to wait for it to replenish.

It's the sort of thing most bought for car bodywork repairs etc.

Tools by Post have a fair selection at reasonable prices.

[Grunff]

Yes, they are compatible, but there are two main types of connector - Uni and PCL.

Yes and no. The pressure is important, but you won't find cases where the compressor's pressure is too high for the tool. What you will find is that many compressors won't deliver enough air per minute for the tool.

Tools have a minimum air requirement (in cfm, cubic feet/minute). Compressors have a rated displacement in CFM, but this isn't a true representation of the air they deliver. The figure you're interested in is the FAD (free air delivery) of a compressor. If this isn't specified, assume it's about 70% of the displacement.

Because many tools require far more air than a small compressor can deliver, the reservoir is used to hold a reserve of compressed air so that you can use these tools.

Most of the oil free hobby compressors are very similar. The one you mention has quite a low output. It would be fine for nailing, for small spray jobs, and for inflating your car tyres. It would be of little use for running air tools (drills/impact wrenches etc).

You have to figure out what you're likely to want to use it for, and work from there.

[Andrew Vevers]

I'd be interested in any response to this. I've got a big industrial compressor which has been great for anything I ask of it, but it's too big since I moved house and now stands outside.

Most of the smaller compressors they have in Halfords and Machine Mart don't seem to deliver enough flow to drive my angle grinder and DA sander - they need around 14 cfm it seems yet the small ones I've looked at only deliver about 7 cfm.

There's one in B&Q that's quite small with a 50 litre tank and is good for

14 cfm and costs about £250. It would fit inside my garage OK and probably suffice for the light use I'd give it, mainly odd car repairs. I want to know what the catch is since nobody else seems to be able to provide such a high flow in a small machine like this.

Andrew

[Colin Blackburn]

In article , grunff232 @ixxa.com says... [...]

Thanks. I was about to ask what FAD was having followed Dave link to tools by post and looked at some of the compressors there.

Presumably this limits the time for which a tool can be continually used. I guess short burst usage is more likely with a lot of the jobs I anticipate.

[...]

I don't anticipate drill and impact wrenches, just pumping, spraying and nailing.

I'd rather not spend several hundred pounds at this stage but I think I do need to check what output I need to blow the borehole before going any further. I think an email to the previous house owner is needed---he took his compressor with him!

Thanks.

Colin

[David Hearn]

I have no experience of these compressors, or the size of them - but are you able to store the compressor out the back of your garage or something? You could build a small box (or outhouse!) around it to keep it out of the weather (though I've no idea whether it minds a damp environment that the autumn/winter often provides) and run the hoses into the garage. That way you'd not need to fit it in the garage, but could still use it.

I'm assuming of course, that its a non-portable one and you've got long hoses - which I'd expect from "big industrial".

D

[Andrew Vevers]

I have considered this . The unit is about 6 feet long and 4 feet high, and fits round the back of my garage but I'm getting a little pressure from my wife - who's even offering to pay for a new one - to hide the monstrosity. I think if I can get it in a smart sort of bunker I'll reduce the objection, but the idea of a smaller unit that I could wheel around is more appealing.

[Andy Hall]

I have one of the little 25 litre/1.5HP models similar to the Screwfix one - branded from SIP. I believe that these all originate from Italy.

I use a whole range of air tools very frequently - nailers of all sizes, wrenches, sanders, mastic gun and spraying.

This small compressor is good enough for nailers - even up to a large Senco framing nailer. These need pressure, but little air volume. It will also handle the other tools but only for brief periods. The receiver empties and the motor runs continuously otherwise. The trouble is that it isn't continuously rated and eventually the thermal cutout operates.

I had a slot of spraying to do recently and anticipate more requirements so decided to invest in a larger model - a 2.2kW one with belt drive and a 150 litre receiver. This is 850x465x1315 so reasonably sized. This will comfortably run the higher air use tools as well.

The small unit is certainly easily portable for small jobs. WHile the larger one is on wheels and moveable, it is pretty heavy (78kg).

.andy

To email, substitute .nospam with .gl

[nightjar]

For safety, you should only use a blow gun that is regulated to a maximum of

2 bar. It is also a good idea to use an air shield nozzle, which creates a cone of air around the blast, to prevent bits from blowing back at you.

Spray painting usually requires an oil-free supply, which means either a specialised compressor of some very effective air treatment. Car tyres will probably also appreciate dry, clean air.

My local supplier has about five different types of connector on the shelf. Look for the make and model type to be sure, but I've yet to buy anything that came with a connector fitted. Usually they just have a BSP tapped hole and need a connector (and, if relevant, a hose) fitted. I prefer coiled nylon hose. It has a good pressure capacity and tends to stay much neater.

I would also recommend fitting a safety release connector for your hose. They have a two-stage release system. The first stage releases the air in the hose, but retains the connector, so the hose cannot flail about. The second stage releases the connector.

As others have said, the important figure is the free air delivery, which must exceed the demand of your equipment.

If you have a reciprocating compressor, it helps to smooth out the pulsing of the pressure and it also gives you welcome release from the noise when the reservoir is at full pressure and the compressor turns off. Personally, I would only use a hydrovane or screw compressor, but they tend to be bigger and more expensive.

Colin Bignell

[NJF]

Its a re-badge generic unit, and for small jobs should be ok, used mine to respray a large van some 15 years ago, so the designs well known....

Niel.

[NJF]

Its a re-badge generic unit, and for small jobs should be ok, used mine to respray a large van some 15 years ago, so the designs well known....

Niel.

[Alan J. Wylie]

^^^

[Rich]

You will always whish you had a little more CFM ( FAD ) I have a £299 14CFM

150 litre tank from Machine Mart and so far it has run every thing that I have got for it, another thing that I have discovered is the internal size of the hoses if it is too small it WILL reduce the FAD at the tool I now run a 3/8" or 10mm internal dia and is much better. It has a 3HP motor which is a pain because it needs a 30amp supply because of the starting current approx 3 times the running current which is 14 amps. I have heard that you can get 3HP soft start motors which can run off a 13amp supply would be a good idear if you have not got a big supply for the compressor.

Rich