I'm new to plasma cutting with a hand-held plasma cutter (as opposed to CNC). Its straightforward to cut with a fence/guide and I am getting good results that way.

However, when I want to freehand a rough shape without setting up a complicated jig, I can't figure out a way to see a line I want to cut. I wear a welding mask on a low setting for eye safety and once it dims I can't see any lines I've drawn on the part.

Does anyone have a good way to safely see a cut line when plasma cutting with a dimming mask?

  • $\begingroup$ What lines have you tried already? chalk? scratch? felt tip? $\endgroup$
    – Solar Mike
    Mar 1 '19 at 15:30
  • $\begingroup$ @SolarMike I've tried all those. The problem is just that the mask makes the entire work piece black, and any markings are indistinguishable. I'm thinking there may be some special reflective or phosphorescent marker or something? $\endgroup$
    – ericksonla
    Mar 1 '19 at 19:12
  • $\begingroup$ Is this an engineering question? $\endgroup$ Mar 1 '19 at 20:40
  • 1
    $\begingroup$ It’s a question that an engineer might well know the answer to - it’s not too broad etc so it’s OK by me $\endgroup$ Mar 1 '19 at 21:45
  • $\begingroup$ It is a question a welder would know how to answer. $\endgroup$ Mar 2 '19 at 23:30

I use the liquid correction pens, the sort of thing used for whiting out marks on paper, Tippex etc. https://uniball.in/shop/img/p/4/3/1/431-thickbox_default.jpg

They produce a reasonably thin line about the same as the kerf of a plasma cutter and work pretty well on most metals also because they are quite bright white the marks are very visible when cutting with the sort of shade of eye protection you are likely to be using for plasma cutting.

Another option is lightly scoring the surface with a thin slitting disk in an angle grinder which can work well for straight lines and shallow curves and has the advantage of not being burned off by the cutting process so you keep a good reference for any final grinding to shape you might need to do.

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    $\begingroup$ You can also uses white Sharpie paint pens and silver Sharpies. The silver ones are available just about anywhere. The whites may need a trip to an art store. $\endgroup$
    – Phil Sweet
    Mar 3 '19 at 15:42

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