Recommended · for some experience
How to Make Double Sided Circuit Boards at Home
Why people recommend it
Mr Carlson documents his toner-transfer process for making double-sided circuit boards at home; people report reliable results when following it with its companion video.
Watch for: follow the stated materials exactly
In their words
There is a good video on Mr Carlson's You Tube channel here which shows how to make double sided boards using toner transfer.
Keith Miller on electronics.stackexchange.com, Nov 2015. CC BY-SA.
Mr Carlson's Lab has a good, much used process: this video first, then this video second.
Kuba hasn't forgotten Monica on electronics.stackexchange.com, Sept 2022. CC BY-SA.