Thread: Recommend High Quality Small Air Compressor

In my mind.

Capacity first.
Noise second.
Cost third.

Buy once, cry once.

Capacity covers a number of things; PSI, charge/recharge/air delivery rate, and tank size, and not all of these things are important to everyone.

Noise is mainly a problem for continuous users.
Unless long range portability is required, noise can be mitigated by use of a sound reducing enclosure and a retractable hose reel will reach most parts of a DIY shed.
If you want to get serious getting the compressor outside and reticulating the air solves the boise problem.

Size/Space can be an issue for some people. eg being able to fit under a bench can be useful in a small shed.

This is has been something I’ve been looking at recently, been really struggling to make a decision. Usually I tend to buy the biggest machines possible but I only need it for some v-nails into picture frames and maybe framing out a bathroom in the shed. A sandblasting setup would be nice but the cfm requirements are pretty huge so it’s just not economical right now, thinking of just getting a 50l Ryobi for $200 and riding it hard till I decide to get a sandblasting setup. Terrible idea?

Originally Posted by bueller

...thinking of just getting a 50l Ryobi for $200 and riding it hard till I decide to get a sandblasting setup. Terrible idea?

Not necessarily, but quality is easier to resell without taking a bath.

I bought a $120 Aldi special about 6-7 years ago. It's ok, it's done the job. It is hell-loud (absolutely ear muffs on, even in its semi enclosure) and there isn't much capacity before it jumps in again. I think it's a 20 litre, but not sure.

For $20 a year - it's been great! But now I really do need bigger capacity (all round) and quieter.

Originally Posted by BobL

If you want to get serious getting the compressor outside and reticulating the air solves the boise problem.

I've actually been thinking about this in my own mind - setting up a compressor outside in an enclosure, and piping compressed air around the shed (ideal, as I could run this at the same time as ducting for the DC which is yet to be permanently installed). I didn't know if this sort of thing was possible to do - and how one might go about setting up a few outlets at strategic locations to plug a short hose into?

Originally Posted by Midnight Man

I've actually been thinking about this in my own mind - setting up a compressor outside in an enclosure, and piping compressed air around the shed (ideal, as I could run this at the same time as ducting for the DC which is yet to be permanently installed). I didn't know if this sort of thing was possible to do - and how one might go about setting up a few outlets at strategic locations to plug a short hose into?

If you don't have far to go this could be a solution: https://www.ebay.com/itm/RapidAir-Ma...wAAOSw4CFYp5rc

They also make 1/2" and 1" systems too.

Originally Posted by rob streeper

If you don't have far to go this could be a solution: https://www.ebay.com/itm/RapidAir-Ma...wAAOSw4CFYp5rc

Aha - many thanks. I didn't realise places made kits for this sort of thing - great to know, and appreciate the tip!

Will go ferret out something local (the one linked doesn't ship over here, but if I get desperate, I can always freight forward one now I have the link).

Thank you Rob!

Originally Posted by Uncle Al

I have one of these compressors, very happy with it. Primarily purchased this model about 5 years ago because of the low noise rating and physical size. I can have a conversation quite easily with it running a couple of metres away from it. I believe the aluminium tanks are a bonus, and I always drain the tank after each use.
I also bought a retractable hose unit, well worth considering for your workshop.

Alan...

Thanks for your remarks. Is the unit sufficiently "powerful" to be used for the occasional sanding? I am planning to make some embroidery frames which would need sanding before finishing.

Yvan

Originally Posted by yvan

Thanks for your remarks. Is the unit sufficiently "powerful" to be used for the occasional sanding? I am planning to make some embroidery frames which would need sanding before finishing.

It's not so much about power but about air flow (sound familiar?) and can the compressor provide it continuously.

Most budget compressor manufacturers overstate their compressor performance and most budget air tool manufacturers understate the air requirements for their tools. The cheaper the compressor and air tool, the more likely they are to do this. The 4" sander I bought many years ago stated on the box that it needed 3.5 CFM which my then cheap 40L, 2.5HP compressor was able to deliver but it turned out the sander needed more than this to run continuously and the compressor eventually ran out of air in about a minute minutes and then could not keep up with the required flow

Air sanders range from about 2" to 6" in diameter and you will often see similar airflow requirements for both sizes but clearly the larger sander will need more flow to function correctly.

Lets just use the typical data provided by the manufacturers
Budget 1HP compressor air flows are typically quoted at about 3 CFM under pressure and cheap sanders are quoted at about the same flow, but given they are under and overstated respectively it's most unlikely that a 1HP compressor can run a sander under any load. To start with the smaller compressors have smaller tanks so the air supply will not last for very long. Remember an air tool like a sander needs to operate under moderately high pressure (90psi) so it can only use about 1/2 the volume of air in a tank before it runs out of the higher end pressure.

A more realistic figure for a 2" sander is about 5CFM (140 L/min) at 90 PSI. A 3CFM (at pressure) compressor with a full 20L tank at 145 psi only has about 25L of air at the required operating pressure so that air will last ~10s before the compressor pump triggers and then the compressor can only supply 3/5 of the required flow so will quickly slow to a halt. Going to a 50L tank does not help that much.

To be sure the tool will function under load you need about double the quoted flow rates of cheap tool and halve the claimed flow rate of budget compressors. This means sanders requires at least a 3HP compressors with the largest tank you can get.

Re: Reticulation
My shed is reticulated with Galvanized 20 mm pipe and I designed and help install our Mens shed system which uses 25mm plastic pressure pipe and Phil Mac irrigation pressure fittings.

The mens shed system has about 40m of pipe that runs in a loop around the main workshop about 3m above the floor. Each length of run is slightly sloped and has a drain (tap) at the end of the slope. There are 6 take offs that first go vertically upwards and bend thru 180º down to bench top height. The sloped runs, drains and upwards take offs all help reduce water accumulating in the lines. This system works really well and is how I would recommend doing any retic air system.

When I did my shed in galv pipe the plastic pressure pipe was out of my budget range given I already had most of the galv connectors from my FIL bottomless galv fittings box. My shed has ~18m of pipe, 7T's, 7 elbows and 6 take offs. I also have a 20m long retractable hose inside the shed for cleaning down chainsaws outside the shed. I can stand in most places in my shed and be within a couple of steps of a compressed air line and air gun..

high quality and quiet? any of the medical compressor (for dental operation) such as Jun Air will be super quiet, if you want industrial Kaeser Compressor can offer you a lot of options.

Originally Posted by Albert

high quality and quiet? any of the medical compressor (for dental operation) such as Jun Air will be super quiet, if you want industrial Kaeser Compressor can offer you a lot of options.

If new none of these are going to be within the OPs price range. There are heaps of used ones on ebay in the US and some are within the OP price range. I saw Jun-Air compressor on GT for $100 a while back - should have grabbed it.

I picked up one of these on sale at the start of the year. Normal price is $799 which is quite a few dollary doos but it is rated for 247 L/min free air delivery. It runs on a 15A circuit, if you only have 10A circuits available, you'll be limited to 2.5hp or less. I found the 50L tank to be just the right size for me to handle alone (the 60L and larger come in massive boxes, you will need a trailer for transport and help to lift them). It also fits neatly under the right hand side wing of my table saw. The blue tank Ironair compressors seem equally as well made.

So far I've used it for driving a brad nailer, stapler, air blower, 2.0mm LVLP spray gun, and a 1.2mm spray gun. It's been fantastic. I can spray an 800x300 panel with acrylic paint using the 2.0mm gun and the unit just starts up again towards the end of the panel. It's no where near as noisy as a direct drive (although hardly quiet) and the build quality is great. No regrets at all.

Originally Posted by Alkahestic

It runs on a 15A circuit, if you only have 10A circuits available, you'll be limited to 2.5hp or less.

I think you should be able to run 3hp on a 10A circuit. It looks to have an induction motor? That would mean a bigger draw right at start-up, but AFAIK the extra draw is short enough for the circuit to be able to cope with.

Originally Posted by FenceFurniture

I think you should be able to run 3hp on a 10A circuit. It looks to have an induction motor? That would mean a bigger draw right at start-up, but AFAIK the extra draw is short enough for the circuit to be able to cope with.

Not compressors, even though they use a compressor head pressure discharge valve the still re-start near maximum load (even worse than a DC) so they have very high start up currents. Besides, the 3HP is a nominal (continuous) figure for the motor. Starting from atmosphere they pull about 2HP but when compressing air at the top of their PSI range this requires about 4HP.

I had a 3HP compressor hooked up to a 15A circuit (ie nothing else on that circuit) and for various reasons was starting the compressor via a 30A Solid State relay and it burnt the 30A relay out after about a dozen starts. The same relay is used on the start circuit of my 3HP DC and that has been running for 5 years without a problem.