SNIP: I use low amperage for heavens sake. 
>>> I run mine at 75 amps but have been wondering if longer at lower amperage is
better. So far nothing’s brittle no problems . . .

SNIP: Not sure about the "hours long fussy edges" people put on their scrapers.
>>> Oh my goodness yes. And SAAB is the answer.

How, you ask?

I used to break old cars when rusted beyond hope, then sell the parts. I do the
same now with wood tools . . . it’s part of my marriage saving plan. She doesn’t
get mad as long as it’s close to break-even.

But before the broken shells headed off to the smelter I’d cut some of the
better panels on the better steel. Your typical MG or Triumph steel was useless
. . . . But I cut and still have the roof panel from a 1968 SAAB model 95 wagon,
and it makes the BEST scrapers. I can cut the shape I want, based on what I’m
doing, then hit the business side with a medium file and it gives me two awesome
“hooks”, one on each side, no annoying burnishing, and no wear on my diamond
stones…..