Air Compressor - what to buy?

[RogerP]

I'm looking to get a compressor to drive a nail-gun, impact wrench, air drill and spray gun. All of this is at amateur level and for very intermittent usage. Paint spraying would just be small parts - nothing major. My workshop is small and overcrowded already so I'm looking for something fairly compact and reasonable quiet. I know "quiet" and "compressor" don't usually go in the same sentence but some must be better than others?

Help and advice appreciated.

 

[dzj]

See the specs/requirements of the tools you intend to use. Pneumatic tools usually require more cfm than a small shop compressor can give.
For the shop you are inquiring about, I'd go for something that will drive the nail and spray gun and leave the rest to electric tools.

 

[Waka]

Roger

You might want to take a look at Screwfix, they've got some really good deals on at the moment. I've just bought myself a small 4.5 ltr Stanley portable compressor, I must admit our needs are different but they have a good range.

 

[Richard S]

Roger,
I think you might be looking for the holy grail! As you say compressor and quiet don't usually go together. I currently have several compressors, a SIP 50ltr with a vertical receiver which is great on the space saving aspect having a very small footprint, but Jesus Christ is it loud! It screams like a banshee. That 24ltr Aldi special was quite quiet, relative to the SIP, however it's obviously built to a price and has fittings made of cream cheese, it's currently damaged beyond economical repair after I dropped something on it and sheared off the air outlet fittings. The 6ltr Axminster is a nice little unit, oil lubricated, again relative to the SIP is reasonably quiet, it's only down side for me was its weight, it's quite hefty and I got fed up lugging it from the van to jobs so replaced it with the Stanley Waka mentioned above. I really wasn't expecting much from this little unit but having had it for about a year now I am very impressed with it. It gets used most days although not on an industrial scale, with a brad nailer or headless pinner and so far has been faultless and it's light.
I was going to build a sound insulated box for the SIP but as we are looking to move house this year all shop projects are on hold. I think once we have moved I will be looking for a larger quieter machine also, I believe that the belt driven type with V cylinders are better in this respect, I worked alongside a chap a week or so ago who was running a nail gun off a SIP industrial size unit that must have been 100+ litres, it was ridiculously big but very quiet. Axminster do a range of more modestly sized belt driven units, if you could get to one of their stores I'm sure they would fire them up and let you see how load they are. A larger receiver will obviously need to re-charge less often when used with low consumption tools such as nailers etc.

Probably all stuff you already know but hope it's some help

Cheers
Richard

 

[woodpig]

Most of the small affordable compressors seem to be of a similar design and as said very noisy. The more affordable quiet compressors are about 3-4 times the cost and don't put out anywhere near the CFM of the noisy ones. You can buy fairly quiet or even very quiet compressors with a good output but they are very expensive in comparison. Luckily for British companies like hydrovane the Chinese don't seem to be able to copy the better designs at the right price point. If you want to keep your sanity in close proximity to a compressor with a decent output then you have two options. Buy a good quiet unit at £1k+ or buy a cheap one and build a sound proof box for it. This has been done by a few folks so do a Google and see if it's something doable for you!

As an aside I wanted to sand blast some modest size components and the general advice was that I needed a huge compressor with a massive output. I tried a very modest compressor at work and proved to myself that for my needs a much smaller unit would do the trick. I bought a 2.5 HP 25 litre compressor for about £120 and built a box in which to sand blast stuff. It worked fine until a house move when I got rid of the box. Some time after we moved I was given a small Clarke sand blasting cabinet and this worked quite well with my compressor. I later read the instructions for the cabinet and noted that my compressor has almost exactly half the recommended power output required!

 

[shed9]

Agree with Waka, some really good deals on at Screwfix at the moment, about to get a similar Stanley or maybe one of the Impax units purely to drive a nail gun at a bench. Can't go wrong at those prices really; http://www.screwfix.com/c/tools/compressors/cat830698

As others have said, driving an impact and other similar air tools is going to need lots of CFM which equates to more noise and budget. You will also find that spraying methods will dictate required CFM quite extensively as well, most gravity guns need about 2.5-3hp at least. When you factor in the required guns, filters and accessories it is often cheaper to get a small HVLP spray package.

I currently run an Axminster 3hp unit in a very crude sound box and have to say I'm very happy with it. Sound is not too bad and the compressor itself has proved to be bullet proof.

Only other advice I can offer is that whatever compressor you get, check what capacitor it uses for start up and buy a cheap spare of Ebay. It will almost definitely need replacing at some stage in its life (especially if its a used compressor) and will save you time and money if you have one to hand.

 

[OLD]

This is a difficult area, my lplv spray gun needs 22psi and 6.2 cfm so a 2.5 hp 9.5 cfm 24ltr from amazon £80 sould have done the job. But no the compressor is running all the time and the pressure at the gun drops quickly i think the 9.5 cfm is piston displacement not output. The answer was to buy another compressor the same and connect the outputs with a Y pipe connector so with a good power supply you have 5hp 19cfm displacement and 48 ltr for £160 . note the 22psi at the gun is done by a small regulator fixed to gun input. And if you just need to nail then use one compressor which is portable but will not stand a heavy impact on the manifold.

 

[RogerP]

Thanks all for the comments, very instructive and helpful, some good tips there.

I'll forget the impact wrench, I hardly ever need to use one these days anyway, and it does mean can I can get away with a cheaper/smaller compressor.

The ScrewFix Impax deals are very tempting ...........

 

[woodfarmer]

The cfm figure can be helped by having a bigger tank.

For years I wanted a 10 bar one twin cylinder but never came across one at a reasonable price. One day I saw a local tool supermarket had a single cylinder 9 bar model at a very affordable price. Luckily it had a 100 litre tank so I went for it ( separate motor and cast iron belt driven pump). A week later another tool supermarket was selling deeply discounted 10 bar twin cylinder machines with a 100 litre tank.

I have managed to do everything I have wanted to do with the one I bought.

If your power supply is weak, It is possible that starting against pressure (when pressure valve kicks in) might be problematical. It was for me here until I installed a 53 amp supply on really heavy duty cables to the workshop. No voltage drops now except a little blip when I start my 5.5hp log splitter

 

[shed9]

If your power supply is weak, It is possible that starting against pressure (when pressure valve kicks in) might be problematical. It was for me here until I installed a 53 amp supply on really heavy duty cables to the workshop. No voltage drops now except a little blip when I start my 5.5hp log splitter

That a really good point, I know a lot of people whose circuit breakers trip with compressors, albeit larger units.