Historical clue formulations

• Connect with a flame — 2025-09-20
• Join, in a way — 2025-03-08
• Form a connection where sparks fly — 2024-03-29
• Fuse, as metal — 2024-01-16
• Fuse — 2023-01-25
• Metalworker's union — 2021-10-16
• Join together, in a way — 2020-06-04
• Join together — 2017-02-23
• Make one — 2015-01-24
• Metalworker's union? — 2013-06-01
• Make inseparable — 2013-05-25
• Join, in a way — 2013-04-14
• Unite under fire? — 2011-08-23
• Join with a blowtorch — 2010-10-19
• Ironworker's union? — 2010-04-07
• Tuesday in Hollywood — 2008-12-24
• Join with a blowtorch — 2008-10-06
• Solder — 2006-12-18
• Unite — 2002-03-17
• Join of arc? — 2001-07-11
• Join — 2001-05-10
• Fuse — 1999-04-07
• Connect, as girders — 1997-09-08
• Fuse — 1995-08-28
• Unite — 1995-08-19