Unmoderated newsgroups like this get out of control so I'm wondering
what else is out there.

I like eng-tips, even though it's very commercial and "promoting,
selling, recruiting and student posting are not allowed in the
forums." They have a Metal and Metallurgy Engineering forum at
http://tinyurl.com/77h27eu and a Welding, Bonding & Fastener
Engineering forum at http://tinyurl.com/7anoxjy

Doityourself.com has a Welding and Metalworking forum at http://tinyurl.com/7zrolg3

Anything else?