I have met Carl in person a couple of times.  He reached out to me out of the blue, and said... "bring your new welder over and spend a few hours".  I reluctantly did (wanting not to be embarrassed), and he graciously spent an afternoon teaching me how to properly weld using my new MIG machine.  Prior and only time I ever welded was 40 years ago using a stick machine, in a college engineering shop class.  I learned a bunch and am grateful (too bad I couldn't have taken video of me being schooled).
I think he enjoyed playing with a new machine (to him) and seeing what it could do and how it compared to other machines.  I think he likes challenge the welder, push past the welder spec max thickness, go hot as it can, and then do legit destructive joint testing.
I really appreciate his knowledge contributed here on TBN, and especially him wanting to personally help a newbie he didn't know from Adam.  I'm sure a few others that met Carl in person could attest to his character as well.  No softy... a serious no BS welder who worked on iconic structures here in the PNW, who unfortunately suffered from a serious bad accident at work that probably should have killed him.  As the saying goes, when life serves you lemons, make lemonade.  I think he leveraged that disability into donating his time to help others learn some of his trade.
Hearing people make wiseazz remarks about people they don't know... well... I think Terry summed it up best.
I am hoping Shield Arc is doing well and we hear from him soon!  If not... I wish the best for him.  And yes, you can call me a softy now.