Hi George,
Nice idea for a topic...it combines my love of tinplate/prewar steam switchers along with my love of trying to be frugal! I say "trying" because I sometimes buy basket cases and the last one needed lots of repairs which was a whole separate thread.
https://ogrforum.ogaugerr.com/t...rewar-steam-switcher
One of those locomotives, a #230 had some prior abuse where the headlight had a chunk missing. My friend and I used Bondo to rebuild that headlight's housing. The housing also has a raised rim around it so it was a fairly involved repair, but the Bondo worked great and with being patient and some sandpaper, it was pretty easy. I think we inserted a pencil at one point to keep the round shape needed for the headlight housing to allow the headlight lens to be installed later. The repair came out so well, you cannot tell there was work done on it.
You also mentioned JB Weld. That stuff is great and should be on everyone's workbench. I've used it to attach marker lights and to attach a homemade cab step made out of copper and JB Weld.
Tom
