Recommended
Eurocircuits - how to make a 4-layer PCB (full version)
Why people recommend it
Follows a commercial four-layer PCB through every production step; cited for questions on layer alignment, etch resist and why fabs use so much water.
Watch for: the wet process around 14:25
In their words
And PCB factory uses a fair bit of water; look at this part of the process.
got trolled too much this week on arduino.stackexchange.com, Nov 2015. CC BY-SA.
Here is a reference video, scroll to video time 19:22: youtube.com/watch?v=sIV0icM_Ujo
S To on electronics.stackexchange.com, Dec 2020. CC BY-SA.
Eurocircuits seems to have an excellent video on the subject:
jms on electronics.stackexchange.com, Dec 2015. CC BY-SA.
