I am having a bit of trouble finding a good answer to this. I know stainless requires a special flux to break down the oxide barrier. I have found a few different options and some state their composition; however, I am unclear on which are best used in a potable water/food application. I came across one that specifically stated that it was not for use in potable water systems.
What should I be looking for in a flux to make sure my solders are food safe?
You want Stay-Clean Liquid Flux by Harris. Anything else is questionable. It’s the dope sh!t ;D
After soldering, clean the burnt flux with fresh flux. Then clean the fresh flux with acetone. Then a repassivizing step with with BKF or other [qualifying] acidic compound should be sufficient.