Hand cutting 3/8" A36 using a respected 65A machine, with compressed air, fresh consumables. Inside the heat effected zone I'm seeing the classic red iron oxide deposit, The compressed air supply is fed from a refrigerated air dryer rated at 20 CFM,followed up by the ubiquitous toilet paper cartridge
Cut quality otherwise seems pretty good for a drag cut.
Is the red, residue normal or do I need to revisit my air supply quality with respect to water removal?
Cyclotronguy
Not sure what power source your using, but here we run all Hypertherm plasma generators, both air and high definition.
That said a 65 amp machine will pull around 7 SCFM@ 85 PSI, not sure of the size of your compressor, but your air drier at 20 SCFM certainly would be sufficient, as long as it is working well, does it ever discharge moisture?. I personally like the Motorguard filters, just keep up on them as the aluminum tends to break down internally if the filter gets too saturated and sets long term. If your compressor is not cycling during cutting then you very well could be dropping below the recommend SCFM/PSI. Although you should see that in your cut quality or a plasma generator fault warning/shut down.
Red within the cut is not all that surprising, is your A-36 clean, oil film, large amounts of scale, etc. What ever is on the outside of the plate as well as inside in the case of Russian steel, (but that's another story), becomes part of the plasma stream.
A few years back some crap steel out of Ukraine was so heavily pickled even after a good cleaning we got some odd discoloration around the outside of the cut.
Your preforming free hand plasma cutting so I would think that your not shooting for a super precision kurf quality cut.
I think I would skip on Nitrogen and most certainly NOT OX.