Plasma cutting air mix

[J_J]

Since the plasma cutter should use clean, dry, oil free air.

Do you think a mix of 25 psi oxygen/50 psi air would give a cleaner and deeper cut?

How about any of the other gases?

For mild steel use oxygen plasma and air shield for the best cut quality, lowest dross levels, minimal rework, excellent weldability and highest cutting speed/productivity.

Illustrated Guide to Plasma Gas Selection - How to Choose the Best Gases

 

[muddstopper]

JJ, I am by far no expert. By reading thru the link you provided, it would appear that adding O2 to your air supply should work well. Not sure how you plan on mixing the air and O2 to the torch. I assume thru the use of a pair of flow regulators. I do think that you might see a pretty significate increase in the cost per cut if you do decide to use O2. Plasma cutters take a lot of air and would very quickly empty even a large bottle of O2. I would suspect that the use of O2 would increase the temperature and allow for a faster travel speed during cut. Most likely allow for deeper cuts as well. I dont know if you are aware of this or not, but when using oxy/acet for cutting, that it is possible to turn off the acet, once the cut is started, and continue cutting just using O2 to blow the molten metal out of the cut. O2 is a oxidizer and will cause the molten metal to burn as the fuel source for the flame. I suspect that the fact that O2 is a oxidizer that that is why it isnt recommended to use when cutting stainless or aluminum, and I certainly wouldnt want to use it on metals such as magnesium.


What is it you are trying to cut that you feel the need to add O2 to your plasma cutter?

 

[J_J]

I was thinking cleaner and better cuts without having to grind the dross off some parts.

I have a plasma cutting table that I need to assembly and a Lincoln Pro-cut 25 and 55, and was just curios for hobby type work.

 

[muddstopper]

Again, I am no expert, but I believe excessive dross has more to do with proper amperage settings, travel speed, and standoff of the work piece than it does with air. Jim Colt made a post somewhere in this forum about using a plasma torch properly, you might do a search. I think his comments might be buried in another thread about plasma cutters

Found one post you might find useful,, http://www.tractorbynet.com/forums/...cutters-why.html?highlight=plasma#post3854936

 

[Fifelaker]

The plasma table at school is very clean when set up correctly. Muddstopper is on the right path with amps, travel speed, standoff and air pressure. I have a home made track torch that is used with A/O if I get every thing set correctly there is very little clean up if any.

 

[muddstopper]

I use a straight edge, as my track torch. One of these days I am going to build a plasma cutting table, but to many irons in the fire right now

 

[blueriver]

I'm new to the plasma and CNC table world ... Have made a lot of practice cuts and wasted a few 5x10 sheets of 14 gauge .. I added a water pan which made a world of difference next step is THC and Floating head .. I have found for my situation 70 lbs of air and proper amps and speed are key elements for smooth cuts and minimum dross ... Here's a piece today cut from 14ga 70 lbs 30 amps. 80 imp

 

[Mark @ Everlast]

Do not! Not unless you have a torch rated for it. That's a good way to get hurt. They use 02 on Hi Def systems but they are specially designed for it. IF you want to use an alternative gas, use Nitrogen with a regulator. It'll make a good, clean cut if used by itself.

 

[Reverser]

I'm new to the plasma and CNC table world ... Have made a lot of practice cuts and wasted a few 5x10 sheets of 14 gauge .. I added a water pan which made a world of difference next step is THC and Floating head .. I have found for my situation 70 lbs of air and proper amps and speed are key elements for smooth cuts and minimum dross ... Here's a piece today cut from 14ga 70 lbs 30 amps. 80 imp

Looks good.
What plasma cutter do you have?

 

[blueriver]

Looks good. What plasma cutter do you have?

I have 2 ... A longevity 62i that is dedicated to the table and a longevity 80i that's on the welder cart