polluted air lines ( oil and rust) inside plasma torch

[plasmatroll]

Dear all,
I need Your help and expertise,
I have bought a "project" 2nd hand Cebora 60A handheld plasma cutter. PC Sound 6061/T.
The ad says" sold as it is, may require some maintenance as it was used a bit"
Looking inside the nozzle, I saw gray residues built up , which led med to reading and learning about the necessity of absolutely clean ( and dried ) air.
My machine came from a tool rental company and I suspect this air detail was not made clear for the renting customer.
As the machine was returned ( I presume with a complaint), the workshop tried to fix it by changing electrode and maybe nozzle.
( I presume still the same effect) / or clogged electrode once more .
The the workshop gave up and sold it as a "project" repair machine ( to me)
I have some experience in the field of repairs, function of various sorts of tools and machinery, but no plasma cutter yet.

Opening the covers of the machine, the inside looked new and unused, cooling air channels were a bit dusty, but that could also be due to storage in a workshop.
Head , handle and hose package did not show signs of long use / wear.

I disconnected filter / water separator from line going inside the machine, filter and inside looked dry.
The connecting hose was pretty oily inside and rubbing it inside with a Q-tip cotton swab, coloured the Q-tip earthy brown.
Cleaning the hose with brake cleaner, followed by a paper towel blown through, it seemed as clean as I could get it.
Electric solenoids ( 2 stk) also quite oily were also cleaned with brake cleaner and compressed air ( and activated to open / close with electric current directly.
The cutting head was disassembled as far as possible and lots of brake cleaner blown through the whole hose ( fairly oily) package both ways until it was only dry air comming out.

Now all components are dry, clean and assembled, new consumables arrived and the torch ready for a test run in a few days.

Is there any experience / chance that there might be more damage to the torch / electronics from use of pretty oily air supply ?

What would you recommend for med to check, do, or install BEFORE the test run ?
I am exited to read Your comments and suggestions !

thanks in advance
from the North,

Matthias

[robertspark]

oil in the air (lots of oil!) is a sign that the compressor rings are worn if it is a reciprocating compressor (piston driven)..... or.... there is an oiler I'm the wrong place for air tools.

you can use oil filters to remove the oil.... but it may require frequent filter replacement is the compressor is very worn.

worn compressor = lots of oil in the air lines = lack of air pressure = lower air volume = compressor running more frequently than it should...... a compressor normally has a duty cycle 50% duty cycle = 5mins run time in 10 mins

[plasmatroll]

thanks robertspark for Your post,
now I know the reason for the oil in my torch !
My compressor has not an oily pressure line and I 've never jused a tool oiler , so that should be fine.
My compressor now delivers 255l/ min, whereas the plasma torch demands 130l/min , so I hope the duty cycle will work out.
Cutting manually only at the moment, but planning a small cnc table eventually.
I will testrun the torch next week and report back.

[robertspark]

how did you test the delivery flow rate?

at what pressure was the flow rate tested?

[plasmatroll]

Hi robertspark,
these are the nominal values written on the compressor and on the torch.
Looking closer, I noticed that it compresses 255 l/min = 9CFM, but only delivers 165 l/min 5,83 CFM at 10 bar / 145 PSI as it says on the compressor. The torch consumes 130l/min at 5 bar ( 4,5 CFM at 72 PSI) , also nominal value from description.

if I'm right, I would need a flowmeter with 2,75 litres per second, which I consider quite a lot, but I do not have one.
As my torch is handheld, I could take olnger breaks in case the compressor is cycling too often.
Are there differences between nominal and actual flow in Your experience? If so, how much would it differ?

Thanks for Your replies, they are much appreciated!

Matthias