Solder pen. By Blondihacks. 17:11 video:
https://www.youtube.com/watch?v=cTYXz9IQxDs
Previously:
https://www.homemadetools.net/forum/...861#post179211
https://www.homemadetools.net/forum/...723#post136802
https://www.homemadetools.net/forum/...029#post129845
https://www.homemadetools.net/forum/...4315#post79736
https://www.homemadetools.net/forum/...3474#post99197
