Air Compressor sizes and air filters/water separators

Just wondering what sizes of compressors are you guys using and your air filter/water separators have you guys been having success with?

Link to NAILI

I have a 33 gallon air compressor and was hoping that would be large enough to start out with but still need to purchase a air filter/water separators and don’t know what is a good product for specifically plasma cutting. I will be using the Vipercut 30 and eventually will probably purchase a Hypertherm 45.

Its more the output of your compressor vs size. A smaller compressor is going to run more and limit you to shorter cuts (there seems to be many users using a 30 gallon compressor with no issues), but you need to pay attention to the CFM’s…

The Vipercut 30 requires 6 cfms at 55-75 PSI.

The Hyperterm 45 requires 6 cfms at 90 PSI.

You’ll want to make sure that whichever cutter you go with your compressor can, at a minimum, meet those specs.

My set up a 60 gallon Husky compressor, Hypertherm 45 and multiple drop lines and filters for moisture control. I started with the Razorweld 45. I used it once and switched the the Hypertherm. If you plan on eventually going that route just buy the Hypertherm and be done with it, you wont regret it.

The company is the world’s best inline compressed air filter supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.

I run a Motorguard M26 filter right before the Plasma. The M26 and M60 is a filter made for Plasma cutting systems and works great. I am running a Eastwood QST-30/60 Scroll compressor with a air cooler of over 50’ with 3 drip legs then a water/separator/filter then copper lines around the shop with a 12" drip leg at every connection point and then the M26 right before the hose to the Plasma and I have zero moisture issues. Not a cheap setup but a trouble free system for Plasma and a Blast cabinet and powder coating.

http://motorguard.com/air_2_6.html

I have what looks just like jamesdhatch has except i also have 2 more with filters and water separaters with drains that are all hooked together in one nice mountable peice. was like 105 bucks on ebay i think. And the one on the plasma cutter also. I leave the drain on compressor seep all the time. Damp and and cold here and no issues yet. https://www.ebay.com/itm/1-2-COMPRESSED-AIR-INLINE-FILTER-DESICCANT-DRYER-3-STAGE-GOOD-FOR-PLASMA-CUTTER/?hash=item3ab6a91d11

I’ve found (the hard way) that it’s much better to dry the air all you can BEFORE it is stored in the tank. I live by the beach, and humidity was often a problem. Without an inline dryer my paint guns would always sputter and the plasma cutter had issues. My compressor before modifying would get LOTS of water into the tank which isnt good for either the tank or your tools, and a separator after the regulator didn’t stop moisture in the lines. I drained a much higher volume of water from the tank than from the separator.

What fixed it was to mount a four pass oil cooler after the compressor but before the tank. The lower line of the cooler goes to the inlet of a filter/separator which captures the water before the air goes into the tank. I now get next to zero water from the tank drain, but have to keep up with the filter drain.
Behind the cooler is a pair of large flat 120V “muffin” fans which run when the compressor is on.
I still keep the Motorguard M26 filter at the plasma cutter, but now the elements seem to last forever.

I have the opportunity to get a 140 gallon tank for free(was a propane tank in its earlier life). I presently have a 30 gallon air compressor/tank combo. I thought it might make sense to get another air compressor pump for the 140 gallon tank from Harbor Freight. Is 140 gallons overkill? If it wasn’t free I would not consider getting more than a 60 gallon air compressor/tank combo for the Crossfire Pro I will be getting in April. I can get a 5 hp air compressor pump from Harbor freight for $132 after 20% discount. Seems like it is worth it. The pump I’m considering has user reviews that say they fill two 60 gallon tanks without strain. Pump specifications say that it delivers 17.3 CFM @ 40 PSI and 15.2 CPM @ 90 PSI. Any advice or comments would be appreciated.

I would be weary of that pump from HF, if it is not a 2 stage compressor then it most likely not made to build pressure much past 90 lbs. My plasma cutter cuts best at 85 lbs, there is not enough room there for comfort. 140 lb would serve you better, that tank is ideal though with the right compressor. Let’s face it, you spent alot of money on that crossfire pro, I would use the compressor you have now untill you can get a 5hp, 2 stage, compressor pump that will last you many years. just my 2 cents

If you want to learn more, please visit our website hydraulic driven air compressors.

Thanks Avalon,
I have read the other threads, what i really wanted was a link to an actual filter that i could buy from the uk. I was hoping not to use the Ali Express type websites but buy from a UK supplier, was going to order the compressor from amazon and the whips/fittings from Best fittings leaving just the filter which I intend to cable tie to a table leg, have the compressor on the floor and fill my HW100K on the table top.C

You can usually find them on Amazon/eBay, but at twice the price and they are often sent from China anyway. The table leg is exactly how I did it - works really well using whip from compressor to filter and filter to gun/bottle.

Why is anything at the compressor end a waste of time? Just curious, I’ve got the elltech compressor and double up on filters, surely a second one on there is better than not having it.

In our application, we want our air to be as dry as possible, breathing air is over 99.9% ‘dry’. Home compressors are nowhere near that, but they are OK as long as you filter them properly. Obvious statements first, the longer you run/fill, the more of an issue this is, if you are just topping up a small reservoir to a low pressure it’s perfectly possible to ‘get away’ with doing a lot of things that I would suggest are bad ideas.

Think about how the compressor works, the act of compressing the air causes a significant proportion of the moisture to fall out as part of the process, this moisture generally makes its way through to the outlet and whip, then pools in the lowest point. If you have done something silly like put your bottle or gun lower than your compressor then it’s getting wet, hence why I say that’s a bad idea.

As the run time increases, more water accumulates, if we add a horizontal filter, it pools in the filter, the obvious solution to this is to dismantle and dry/rebuild your filters on each use. Yea, obviously not happening. That means things like galvanic corrosion where the contaminated water and two different metals react with the weaker being eaten away, throw in the potential reaction between the desiccant and water and it can get quite nasty over time.

It’s much easier and cheaper to use two whips, the first going up from the compressor to a primary filter, then another whip to the secondary filter and gun. You could just use one of the medium size gold filters if you prefer, but doing either of those options requires much less filter management.

Also when you finish running and disconnect the whip, you see that water that falls out? Well when you turn on the compressor with no whip connected, it blows a load more out. This would all end up in your horizontal filter normally. This is one of the areas Hills did something very simple/effective on the EC3K, they added an expansion chamber with the outlet at the top and bleed at the bottom, the moisture pools here due to gravity and is vented when you vent the line, I get a lot less moisture in my filters from the Hills than I did for the 12v units and fill a lot more air by volume.

You can usually find them on Amazon/eBay, but at twice the price and they are often sent from China anyway.


In our application, we want our air to be as dry as possible, breathing air is over 99.9% ‘dry’. Home compressors are nowhere near that, but they are OK as long as you filter them properly. Obvious statements first, the longer you run/fill, the more of an issue this is, if you are just topping up a small reservoir to a low pressure it’s perfectly possible to ‘get away’ with doing a lot of things that I would suggest are bad ideas.

Think about how the compressor works, the act of compressing the air causes a significant proportion of the moisture to fall out as part of the process, this moisture generally makes its way through to the outlet and whip, then pools in the lowest point. If you have done something silly like put your bottle or gun lower than your compressor then it’s getting wet, hence why I say that’s a bad idea.

As the run time increases, more water accumulates, if we add a horizontal filter, it pools in the filter, the obvious solution to this is to dismantle and dry/rebuild your filters on each use. Yea, obviously not happening. That means things like galvanic corrosion where the contaminated water and two different metals react with the weaker being eaten away, throw in the potential reaction between the desiccant and water and it can get quite nasty over time.

It’s much easier and cheaper to use two whips, the first going up from the compressor to a primary filter, then another whip to the secondary filter and gun. You could just use one of the medium size gold filters if you prefer, but doing either of those options requires much less filter management.

Also when you finish running and disconnect the whip, you see that water that falls out? Well when you turn on the compressor with no whip connected, it blows a load more out. This would all end up in your horizontal filter normally.

So a second filter is good but just better put onto a second line and both vertical. I have my main one vertical when I fill and I’ve just topped up a 2lt bottle from 190 to 290 bar, nothing in the second filter at all, though I haven’t checked the first one. Thanks for the reply. Cheers.