So I've had good luck with the toner transfer method and ferric chloride on PCBs but sometimes I need to fix things with a marker. I found a regular sharpie didn't do the trick so I bought a special Industrial Sharpie.
It was advertised as being a "specially formulated ink for industrial use" that "remains permanent under most chemical washes"
I guess Ferric Chloride isn't one of those chemical washes
Could anyone recommend a marker to use that will survive a ferric chloride bath?