New Compressor

[Retroanaconda]

Gonna get myself an air compressor for the workshop, it will be used for air tools (primarily a decent impact gun), maybe a bit of spraying, doing tyres etc. so probably doesn't need to be a massive one but I figured it's probably one of those things where you can't go too big - right?

When I ran the power out to the building I ensured I had good capacity, the incoming supply is off a 40A MCB in the house and then in the slave consumer unit I have (as well as ring main and lighting) a 16A welder circuit and crucially a 20A circuit for a compressor. So I am able to go for a decent sized unit without worrying about running it off a 13A plug. Unfortunately I am limited to single phase. I will build a small shed at the back of the workshop to house the unit so as to save valuable floor space, power will be run through a suitably rated isolator in an accessible location inside the building so that I can stop it running when not in use. Noise isn't a major problem, the nearest neighbour is 200-300yds away and hopefully being inside an enclosure will muffle the sound somewhat. I was thinking of using copper pipe for the airlines, running it to a few coupling points around the walls for the flexi hoses.

I have so far narrowed it down to this unit, which seems to be good value to me:

http://www.airsupplies.co.uk/abac-b3915-200-pro-a39b-200-fm3-belt-driven-air-compressor-3-hp-200-litre-14-cfm-single-or-three-phase

Okay so 200L is probably a big overkill, but it's not much more than the 150L version and since space is not an issue it seems sensible to go for the biggest receiver size to minimise running when using more air-hungry equipment.

Any thoughts that may help with this, suggestions of alternatives if the above would not be suitable for my needs, experience with power supplies, housing compressors in separate enclosures etc, would all be appreciated.

Thanks

[qwakers]

no need to use copper pipe thats the expensive way of doing it.

http://www.screwfix.com/p/floplast-pe-x-barrier-pipe-white-22mm-x-25m/38914

first thing to note is volume is everything so use 22 or 28mm pipe.

and no you cant go too big on a compressor.

 

another thing to add to the list of accessories is....

http://www.screwfix.com/p/air-tool-filter-regulator/3109h

(thats the one i have its cheap its nasty but it works better than the review suggests.)

[qwakers]

oh and for what you want that compressor is waaaay more than youll need.

https://www.machinemart.co.uk/p/clarke-industrial-aircompressor-xev16100230v/

 

that will do everything you want and more and most importantly its cfm rating is the same so it will keep up just fine. the only difference tank size makes is for how long it takes before the pump has to cut in.

 

plus if you wait til a vat free code comes in youll get it even cheaper....

[Retroanaconda]

Thanks qwakers.

One of the reasons for wanting copper piping was for it to add a bit of cooling, with a drop leg for draining water out. I could run copper through into the building as far as the filters/regulator, then change to plastic for the run(s) out perhaps? How does plastic deal with oil in the air?

Compressor size is a bit more subjective I suppose, and depends on the level of use.

[Ed Poore]

I'm just throwing it out there James but I haven't had much luck with air powered impact tools. I'm sure part of it has been that the tools themselves haven't been the best but the only time one actually succeeded over a breaker bar required a V4 belt driven 3 phase compressor and a 1" impact drive...

The setup at my parents usually involved having to move the compressor into the barn to work on and then I found (in hindsight) the pipes are just annoying.

After the saga with wheel bearings on the way to Scotland a few months ago I had the opportunity to play with one of these, I was so impressed I ended up buying one. Given I was buying into the batteries as well it wasn't a cheap purchase but it's proven useful as I can chuck it in the back of the 110 easily enough. I've subsequently bought a drill to replace my old Makita and Dad has a smaller impact hammer, circular saw and previous gen drill. He actually wanted to drop the tow ball on his Shogun down a bit but couldn't loosen the M20 bolts holding it in place. I put a socket on the nut, impact hammer on the other, pulled the trigger and simply got dragged under the vehicle by the wrench to much hilarity. Once we found a bit of scaffolding pole to wedge against the floor it cracked the nut off easily.

I'm not saying a compressor is a bad shout but I've found the battery option to be invaluable as you can use them anywhere. On well under a single charge the drill (with Dad's 4Ah batteries not my 5Ah ones, they do now do a 9Ah) comfortably managed to drill something like 12 1.5" diameter holes through 10" posts in the fields when I was putting up a fence on the farm. I know Dad managed to clad almost all the roof of a 20x8m barn roof and walls using the small impact hammer and hex headed screws.

Sure you can't spray paint and you're a bit more limited on tools that are available but for me they trump the compressor option because they're usable anywhere which is a big win for me. One you've got a set of batteries though the bare tools aren't too bad. And there are 3d printed designs now to let you use batteries in different brands of tools...

[UdderlyOffroad]

13 hours ago, qwakers said:

no need to use copper pipe thats the expensive way of doing it.

http://www.screwfix.com/p/floplast-pe-x-barrier-pipe-white-22mm-x-25m/38914

first thing to note is volume is everything so use 22 or 28mm pipe.

and no you cant go too big on a compressor.

The screwfix site appears to be down at the moment, but push-fit fittings usually specifically exclude compressed air use. Toolstation do a range of fittings meant for compressed air applications, and they don't seem too expensive compared to their meant-for-water cousins.  I think I recall a thread where HfH fitted his shed out with them for about £100 of outlay?

That said I'm going for copper as I've been squirreling away off-cuts of copper pipe; I have essentially the same plan as James for my new garage.  I was going to try and incorporate a PVC wastepipe-based dust extraction system into the compressor dog house, but that's a topic for another thread.

 

9 hours ago, Ed Poore said:

I'm just throwing it out there James but I haven't had much luck with air powered impact tools. I'm sure part of it has been that the tools themselves haven't been the best but the only time one actually succeeded over a breaker bar required a V4 belt driven 3 phase compressor and a 1" impact drive...

The setup at my parents usually involved having to move the compressor into the barn to work on and then I found (in hindsight) the pipes are just annoying.

When I made my living with my tools, even my £15 ebay cheapie impact gun would crack nuts all day, provided it was connected to a decent size workshop air compressor+tank.  At home with my 3HP, 50l Lidl special, not so much.  Same goes for my air drill and grinder.

I can see why if you're on a farm with many outbuildings, and kit to maintain quite literally 'in the field', dragging air compressors round quickly becomes old.  But if you've a got a fixed workshop/shed, I think I'd rather spend the money on a proper compressor setup, with the biggest tank size you can afford.

Incidentally, I noted on a recent trip to my local independent tyre fitters, they've switched back from Milwaukees to air-driven impacts.

Just my £0.02 however...

Matt

[Ed Poore]

8 minutes ago, UdderlyOffroad said:

When I made my living with my tools, even my £15 ebay cheapie impact gun would crack nuts all day, provided it was connected to a decent size workshop air compressor+tank.  At home with my 3HP, 50l Lidl special, not so much.  Same goes for my air drill and grinder.

I can see why if you're on a farm with many outbuildings, and kit to maintain quite literally 'in the field', dragging air compressors round quickly becomes old.  But if you've a got a fixed workshop/shed, I think I'd rather spend the money on a proper compressor setup, with the biggest tank size you can afford.

Incidentally, I noted on a recent trip to my local independent tyre fitters, they've switched back from Milwaukees to air-driven impacts.

I agree if it's going to be a permanent install then compressor is almost certainly the way forward, particularly in James' situation where he doesn't have neighbours. The farm is OK but at home in Surrey I think the neighbours would be a little annoyed if I had a compressor running in the garden shed... If I had the option then I'd have a fixed compressor (I have a little one but not plumbed in yet) but given my situations I'd still stick with the battery ones because even if I'm not on the farm I do chuck them in when on trip around the country / Europe and they've proven useful so far. Cables / hoses are just annoying when I can grab it and go straight to work.

We only had a cheapo Machine Mart impact hammer but inevitably the only time it came out was when I failed to crack them off with a breaker bar. This was even with new V-Twin 200l compressor that we replaced the old 50l one with and even then it usually struggled if it did succeed at all.

Re: tyre fitters - I can see if you have more people using them then battery operated tools become quite expensive as you don't just have to buy the tool but a new set of batteries for the new guy. Whereas with a compressor you only really need the tool and perhaps a bit more pipework.

I had heard things about people switching away from Milwaukee but they tended to be the brushed motors whereas the brush-less ones appear to be a bit more robust. We had the recommendation from some rally friends and given the abuse they give them then they should stand up to what we need them for...

[Retroanaconda]

2 hours ago, UdderlyOffroad said:

When I made my living with my tools, even my £15 ebay cheapie impact gun would crack nuts all day, provided it was connected to a decent size workshop air compressor+tank.  At home with my 3HP, 50l Lidl special, not so much.  Same goes for my air drill and grinder.

So are you saying that your 3hp Compressor isn't man enough to crack off (for example) crankshaft pulley bolts, or over-tightened wheel nuts? That's the sort of thing I would be getting an impact wrench for to save getting the breaker bar out all the time. Due to my single-phase supply 3hp is about the limit of the power of the thing, which seems to get you about 10bar/150psi. Forgive my ignorance but presumably it is this figure that dictates the 'power' of the system, with the tank size just increasing time before the motor kicks in as above? If a 3hp system cannot do what I need then that would be good to know!

It will be a permanent install yes. I do like the modern battery guns though, and wouldn't rule one out for mobile works away from the workshop in the future.

[Peaklander]

I think that the "power" is the bar-litres and the ability of your pipework to deliver sufficient volume of air at the pressure required by the air tool at the end of the pipework. So it's not so much the power of the compressor, it is its ability to raise the tank volume to the correct pressure. If it can do this then it has done its job. A smaller compressor will take much longer to replenish the tank.

If you can wait long enough, the tank will be at, say 250litres and 7 Bar and you have that volume available at that pressure to pull down. As you remove the air, the pressure will fall until eventually you are left with 250litres at 0 bar (atmospheric) and there's no more flow. Obviously way earlier your compressor has switched back in to start to replenish. If you are not operating the air tool then fine, it will come back at the "fill" rate that the compressor can deliver. If you are still using the tool then the compressor has to at least match the bar-litres being consumed by the tool. If it is lower then it will chase the tank pressure but fail to top it up fast enough and pressure will continue to fall and you will have to stop.

I don't have data of the consumption of air tools but if you do have it, for a particularly thirsty tool then you could work out how many bar-litres it will pull from the tank and so how long it will function for as the pressure reduces.

So in summary, tank volume first (unless you have a huge compressor that can supply the volume your tool draws) and pipework size to minimise pressure drop down the line to the tool. Then it's all about the duty cycle at which you are forced to operate. As soon as you stop drawing air, the compressor begins to refill what's been drawn. The lower the bar litres you can hold at the tank then the lower is the duty at which you can operate.

I hope that makes some sense; it's just my understanding of what's happening.

 

[steve b]

As someone said earlier , it's not just pressure but volume(flow) too so the shortest run of the biggest bore pipe from the compressor to the workshop and a big main round the workshop 20+mm . Hiflow couplers and at least a 12mm pipe to the gun , preferably 16mm  . You could also add a smaller reservoir  ~ 20l at the coupler you are going to use the impact gun from . HGV plastic air pipe and push-fit connectors would be a pretty simple way to pipe it all . My compressor is a Clarke 14cfm. single phase with a 200l tank and 12mm pipework . It works hard when running a DA sander but otherwise is good for everything else incl. the 1" impact gun.

cheers

Steve b

[Retroanaconda]

Thanks gents, lots of good info here.

The pipe run will not be very long, I can do say 4m of 22mm copper to get me to where the reg/filter will sit, then further to that I can do similarly sized plastic if necessary but it's only likely to be another 4m at the most.

I think Machine Mart codes only get sent to you if you have spent with them in the past, but I'll keep my eyes out for a no-VAT code in the meantime anyway.

14cfm/200L seems a good setup. Yes I could probably get away with 100L or 150L but there seems to be no disadvantage to going bigger if I can A: afford it and B: make space. Though I guess when starting the Compressor for the first time in the day there will be a longer delay while it initially fills the tank (unless you leave it pressurised)?

[UdderlyOffroad]

2 hours ago, Retroanaconda said:

So are you saying that your 3hp Compressor isn't man enough to crack off (for example) crankshaft pulley bolts, or over-tightened wheel nuts?

...

before the motor kicks in as above? If a 3hp system cannot do what I need then that would be good to know!

It will be a permanent install yes. I do like the modern battery guns though, and wouldn't rule one out for mobile works away from the workshop in the future.

If my tank was 100l or 150 l am sure it would be ok.  As it is, I've managed to do crankshaft bolts (200tdi) with it, but I prefer to use the breaker on something...expensive.

As others have said, it's about the pressure x volume giving you the largest amount of stored energy for the gun to use.  You can't easily increase the pressure to the gun, so increase the volume.

So yes, if you can afford it, go 200 L.

The second most important thing is lack of restrictions and in the pipework, so in my case that will mean a 22 mm copper main, probably with 15mm drops at the workbench.  But a 22mm drop for the main 'wondering hose' and ditto for the blasting cabinet.

Actually I noticed a decent improvement just by using a good 10mm hose.

And dont get me wrong, having just spent a year doing up a house, I'm very pleased I stumped up for a decent drill and impact driver. But the milwaukees nut-runners are just a little bit too rich, they're almost the price of a decent MIG

[Troll Hunter]

I've got a nominal 6;5 hp/8.5 cfm @ 90psi gas powered mobile compressor which has ridiculously small tanks, since it is a "wheelbarrow" mobile unit.  However, I've connected it to a recovered 100kg propane cylinder.  I reclaimed the cylinder from our local dump and then pressure tested it.  My compressor output is regulated at 125psi so I tested it at 250psi, filled with water and then pressured it from my Kubota tractor hydraulic system. 

Note: Do not pressure test with air since there is far too much energy for safe operation,

[Cynic-al]

Depends how your going to use it, if your doing 1 nut then leaving it 10 minutes you can get away with a large tank and a small pump. Machine mart do a single phase compressor with 2 pumps on which have a staggered start so you can get a higher output with a smaller supply. I guess theres no reason why you couldn't set that up yourself with 2 cheaper compressors if its too spendy. If noise is an issue I notice they also do 'silent' running ones with 3 pumps on but I've never used one. Might be easier than putting up a compressor shed?

For piping I've always just run flexible hose, quick and easy to run, get it in whatever diameter you want and no joints to leak. At work it's all solvent weld plastic which is fine until someone lifts the chequer plate (which is thick enough to take a loaded forklift) on the services trough whilst chasing a mouse and drops it on the pipe. Half the factory was down whilst the repair was done and the joint set

[Retroanaconda]

The compressor shed is as much about space as it is noise, I can't spare the floor space in the building and have plenty to spare out the back, so seemed logical. It won't happen immediately, will probably be a little while until I can get around to concreting a pad and putting up the shed itself, so the compressor would live in the workshop short-term.

A touch of serendipity, just got a no-VAT code through for Machine Mart. So looks like that may be a goer!

Any specific feedback from folks on the Clarke Industrial 'Blue Line' compressors? steve b - you say yours runs your air tools okay, would you recommend the unit as a whole?

[steve b]

Yes , mine is probably over 20 yrs old now and has been trouble free , one motor capacitor in that time . The V4 that runs the Plasma cutter and workshop supply at the fab shop is also a Clarke which again has been ultra reliable too (3 phase) . I'm sure you will find it to be fine for all you need to do .

 

cheers

 

Steve b

[landroversforever]

I've got the slightly larger ABAC one James, 415V and 18cfm (14cfm F.A.D) on a 200L tank. 

Most of the air tools I use often such as the impact gun, die grinder and the air cut off need 14cfm at 90psi. My compressor takes about 5-10mins to fill the tank from empty (I haven't timed it). One thing to take into account is the difference between displacement cfm and free air delivery cfm. The latter being the smaller number and what matters. In the real world that means that I can use any of my tools flat out and when the compressor kicks in I have no loss in speed/power at the tool. Most places quote the cfm figure for the displacement as its bigger and looks better, but watch out for the really low FAD numbers! 

Another thing is draining the tank, I have the compressor up above the bench as you probably know so I extended the drain down to an easily accessible level which means there's no excuse to not drain it. Being outside yours will see similar temps to mine so lots of water condensing. 

A slow air tool thats running out of air but not dropped the tank pressure enough to kick it in has to be one of the most frustrating things in the workshop so go as big and powerful as you can  . 

[Retroanaconda]

Thanks Steve, sounds like they'll do what I need. The no-VAT gets me a good deal so I'm happy with that.

Ross - Machine Mart don't clarify what figure they are using so I presume it's the cylinder displacement. They do an 18cfm single phase model which is only about £30 more than the 14cfm one, however it's a 4hp motor and so they say it has to be hooked up to a 40A supply. I presume this is due to the startup current as a 4hp (3kw) load is only 13A or so at 230V.

I've only got a 20A circuit lined up for the compressor so I would presume that's a no-go. I just double checked the 14cfm unit and even that says it needs a 30A supply - bugger!

For those in the know, is there any leeway in these figures? Are MM being over-cautious or will it really pull that current on startup for long enough to trip the MCB? I've got a type B breaker in there at the moment, but can change it for type C or D as required if necessary to allow for the startup spike.

Given that the incoming supply to the workshop is only a 40A feed I don't think I'd want to up it too much, though I guess I could put a 32A MCB in instead of the 20A which would at least get me to the figure that the 14cfm model demands.

[qwakers]

you cant just increase the mcb size unless the wireing is rated to above the size mcb you want to put it.

 

all the below is assuming your using a radial circuit if its a ring its different

1mm2 11a

1.5mm2 14a

2.5mm2 18.5a

4mm2 25a

6mm2 32a

10mm2 43a

that is all assuming they are in a insulated wall/roof area.

 

 

[Retroanaconda]

The wiring doesn't exist yet, I have the 40A supply into the consumer unit in the workshop (if I recall correctly the chap used 10mm cable). I'll run a new radial circuit out from the MCB to a 32A plug for the compressor, so I can do so in whatever size wire is required.

[qwakers]

then if you do it in 6mm youll be fine

 

[Retroanaconda]

I'm still concerned that I would be, in the case of going for the 18cfm model, running it on a supply that's too small. Machine Mart say 40A supply minimum.

If that's just over-cautiousness on their part and it will happily run off a 32A circuit (including startup current) then that's fine, however if it actually does need a 40A supply I will have to go for the smaller model.

[muddy]

At work ( granted it's 50/50 on site in workshop) there's only one fitter out of 14 running air impact gun. Everyone else is on batt impacts (snap on which are now carp and Milwaukee) and they are just as good imho, the battery grinders are a little slower than mains but it's still rare to pick up a mains one.

 

IMHO I would concentrate on a compressor that will be better for spraying with and move to battery tools in the future, I would be very miffed if I had had a built a lovely vehicle and struggled to paint it because of a small compressor issue.

 

will.

[UdderlyOffroad]

22 hours ago, muddy said:

IMHO I would concentrate on a compressor that will be better for spraying with and move to battery tools in the future, I would be very miffed if I had had a built a lovely vehicle and struggled to paint it because of a small compressor issue.

The two aren't mutually exclusive, quite the opposite in fact.  A compressor good for spraying would be also good for running tools!  True you'd regulate down the air pressure for spraying, but that's not an issue if it's just you in the 'shop.  The other issue would be not running oil in the lines, but then you probably wouldn't do that anyway, a drop of oil 'up the spout' of the tool every day is sufficient.

 

22 hours ago, muddy said:

At work ( granted it's 50/50 on site in workshop) there's only one fitter out of 14 running air impact gun. Everyone else is on batt impacts (snap on which are now carp and Milwaukee) and they are just as good imho, the battery grinders are a little slower than mains but it's still rare to pick up a mains one.

I still maintain that for the keen amateur, you're better off spending your money on a good compressor setup rather than battery powered  - a drill driver is one thing, but the Milwaukee Fuel 1/2" impact is £470 from Toolstation, that'd buy a decent compressor and accessories.  Other opinions are available of course!

Another reason is that even expensive batteries will suffer if not used regularly, meaning that you'll come to use a tool of a weekend and it'll be flat.  I think I'd rather have a properly setup air system and know it's ready to go after 30 seconds of running, than have to faff finding the charger or changing batteries.  Even inspection lights always seem to be going flat at inopportune moments.

Matt

[Bowie69]

Note that is 470 with 2 batteries, you can take 130 off that if you them already.