[delraydella]

Draining your air compressor tank on a regular basis will help keep moisture out of the line, especially in really humid weather.

[Otto Nobedder]

Draining your air compressor tank on a regular basis will help keep moisture out of the line, especially in really humid weather.

Draining is good, but!

Despite the common logic, it has NO effect on the moisture in the line. You might have a 1/4" in the bottom of the tank. You might have 4" in the bottom of the tank. The key words are, "In the bottom of the tank". It's stuff that's already condensed out. It's the water above the "saturation" of the air in the compressor. The humidity of air leaving the tank is not affected by standing water in the bottom.

Steve S

[WerkSpace]

What about using an intercooler to reduce the moisture?
(Cooled air causes the moisture to form into droplets.)

My air compressor has a finned copper loop directly behind the cooling fan.
I believe the idea is to cool the hot compressed air before it reaches the tank.

PS: I got this idea from a recent engine purchase ($300) for my hovercraft project.
I needed 80hp at less than 300lbs. https://www.youtube.com/watch?v=DvYaRuXBACc
I chose the Suzuki 3 cylinder, 1 liter, fuel injected, turbocharged, intercooled engine.
http://www.raven-rotor.com/html/redrive.html (80hp at 159lbs.)

[delraydella]

Sorry Steve, but I gotta disagree with you there. If you have water in the bottom of the tank , it's really easy to tell that if you're using pneumatic tools like a nail gun because you can see the moisture in the air coming out of the exhaust port. It looks like steam. If i drain out the tank from the bottom and get all/most of the water out, and refill it with air, there's an immediate difference in whats coming out. Again, using a nail gun, there's no more moisture coming out of the exhaust.

Of course, it won't get rid of every bit of moisture in the line, but it gets rid of a lot of it.

Other Steve

[Otto Nobedder]

Yes, draining reduces visible moisture in the line. The problem is, when moisture settles in the tank as liquid, the tank air is already saturated. For plasma cutting, it doesn't matter much whether the moisture is visible or not.

I've also noticed when I use my WFO blower, I see moisture in the air regardless whether I've drained the tank or the standpipe (set up as a secondary moisture trap with a low-point drain).

Steve S

[noddybrian]

If the quality of the air from a compressor matters for it's intended use such as food industry / water industry / paint spraying / plasma cutting / breathing / diving - then the air must be cooled considerably prior to effective multi stage filtration - we all largely ignore this when using cheap air tools on cheap compressors but it does matter for some things - plasma cutters hate water vapour as it greatly reduces the consumables life - the small coil of pipe between the compressor and it's tank help slightly with cooling - but nowhere near enough - so most of the water vapour in the air being compressed stays warm enough that a cheap filter near the compressor cannot catch it - a filter is only effective once the air is cold enough for that vapour to condense out - so a filter some distance from the compressor will work better - commercial compressors often have a refridgerant cooler / heat exchanger either in a seperate cabinet or sometimes built in with the compressor prior to filtration - just look in a spray shop / body shop. The water in the tank that has already condensed is'nt the problem.

[Otto Nobedder]

I built a rather complicated system for the paint booth at work. There are dual 80-gal tanks downstream from the compressor, with a heat-exchanger and oil separator between, auto-drains on both tanks, and an 8000 btu air-cooler/dehumidifier after to provide dry air for the two-part epoxy paint our shop uses.

I suspect for the OPs home-shop use, though, the seperator and dessicant pack will likely be adequate, and better than most home users have.

Steve S

[WerkSpace]

Now, I understand the NOTE on my desiccant dryer that suggests to mount it at least 25ft from the compressor. That puzzled me for a while and now I understand that they are simply wanting cooled condensed air prior to filtration. I will make my own intercooler instead.

a filter is only effective once the air is cold enough for that vapour to condense out - so a filter some distance from the compressor will work better.

[arc54]

Wow, that's a lot of info, just wondering if I should move my air filters to the plasma cutter end rather than at the compressor end. To remove as much moisture as possible before entering the plasma cutter or leave it the way it is? Thanks again and keep it coming I'm considering all the options here.

[Otto Nobedder]

At work, we have separater/filters mounted to the carts our cutters are on, so the final filtration is at minimum 100' from the compressor tank (50' overhead pipe to the nearest connection plus 50' of air hose). The separaters stll pick up water, despite an auto-drain on the tank and a stand-pipe with sump and drain.

So, yes, there's a benefit to having the separation occur as far "downstream" as reasonable.

Steve S

[echosixmike]

Google "Franzinator" if you want to make an expansion air/water seperator. If you want to follow that up with a chemical dissicant, it'd probably be near perfect for anything less than lab or commercial use. S/F.....Ken M

[WerkSpace]

A cooling fan over this radiator would make this setup much more efficient.
A thermostatically controlled, electric fan from from a vehicle would work great.

Google "Franzinator" if you want to make an expansion air/water seperator. If you want to follow that up with a chemical dissicant, it'd probably be near perfect for anything less than lab or commercial use. S/F.....Ken M

[arc54]

Today I tried putting the all the filters on the plasma end of the compressed air and had no issues with water in the line. Worked great, thanks for all the advice and recommendations. Thanks Steve

[Otto Nobedder]

Glad it's better for you!

As you see from the other posts, and some of my own comments, there are ways to further improve the system, but you've got to weigh the cost in time and/or money against the price of your consumables and the effort to dress your cut pieces.

Only time will tell if a futher investment can be justified.

Steve S

[arc54]

Thank you, Steve . Eventually once I recoup some money I will upgrade to better filters but for now I'm good. I love having a plasma cutter, unfortunately this completes my toy list. Just kidding Learning tig will be next thanks again

[Turnaround]

I just received, but have not hooked up yet, a Chinese 3 in 1 plasma cutter (about $300). I am a long time O/A user (where the better you cut the less grinding you have to do). I have seen some plasma cutter heads with a wire "guard" on the business end to keep one from dragging the copper tip against the work. Other units seem to have several leaves protruding away from the body to, again, keep one from dragging the copper against the work. Would it be worth while to just trash the supplied handle, and try to adapt an ESAB PT-31 (some one here thought the ESAB might be a replacement torch handle for these Chinese plasma units). AND does that ESAB unit have the wire guard or equivalent protrusion to keep from dragging the copper? And (second AND) if you are capable of electric arc welding (pipe welding school at Aberdeen, MD while in the army) with a consistent short arc, do you even need a guard to keep from dragging the copper. I have to admit that I have never even held a plasma torch so, it may be obvious, I know nothing about plasma cutting.

[450dualsport]

Now, I understand the NOTE on my desiccant dryer that suggests to mount it at least 25ft from the compressor. That puzzled me for a while and now I understand that they are simply wanting cooled condensed air prior to filtration. I will make my own intercooler instead.

I see you have the Princess Auto dessicant dryer. How is it working out? I was thinking of getting one.

[weldin mike 27]

Hey TurnAround,

Most plasmas have a setting for "stand off" and "drag" if your cutter is supplied without any of the bits you have seen, it is a drag tip where the copper is meant to be dragged on the metal. If you want to try a different style, be sure your machine allows for stand off, and then only buy parts for that brand. Im not sure if you can change torches, id say no because they dont want you tospend with another company. Unless they are like mig guns with a euro connector where every brand fits regardless.

Mick

[noddybrian]

The generic Chinese PT31 torch as supplied on most import plasma's up to 40amps is intended to be dragged & as such has a cross shape set of grooves cut into the face to allow some cooling effect & reduce the tendency to stick - I'm told by the UK importer of the Cut 40 machines the life will be improved if these are made more pronounced - I keep meaning to make a fixture to hold them so I can use a bull nose end mill to do this - if you have no mill & want to try I'm told a small chainsaw file works OK - but care must be taken to remove any dross from the hole afterwards - I've never seen a wire stand off for this torch - partly the ceramic shroud is tapered & offers limited attachment area & many plasma's in this class have only HF start & rely on continuity with the work to maintain arc once cutting - if you want to spend £20 " Shop River " has a wheeled guide that doubles up as a trammel that I assume works but the consumables are so cheap for this torch it's barely worth the bother - you can swap torches around to a degree on the imports as most are threaded M16 * 1.5mm or 3/8" BSP which seem to interchange fairly well - in another post someone asked about the suitability of a PT 31 as supplied on a multi-process that featured 50amp cutting & I suggested this was more heat than that torch was good for & he swapped it out to either an SG 51 or 55 ( I can't remember which) he was happy with the results & has much improved cutting depth - depending what amps your machine cuts at this maybe worth while - just remember when ordering consumables there are different nozzle sizes to roughly match your current on some torches ( AG 60 in particular ) - I'd try your machine as supplied first - but " Shop River " has everything you need at good prices if you want to upgrade & the AG 60 does have the wire drag clip available though I'm convinced their a good idea.

Hope that helps.