[Richard Coutts-Smith]

They must be big patches. Always found the accuracy and speed of the ultra thin discs superb.
Do highly recommend a 5in. grinder though: 4in. blade disappears too quick, the 9in. disc is not much thinner than a standard cutting disc so does not make much of a difference. Personally I only use a plasma as a last resort, as I am wary of the toxic crap they put in to the air. Doors open and fans on and face mask.

Sounds like you are enjoying getting to grips with this new field.
Rich,