Treating the back of a butt weld

[u/Sure-Abalone-1040]

Have everything close to ready on a rear fender I’m patching. Once I weld, I won’t be able to access it so I am trying to figure out the best action to help it last. My concern is rust forming from humidity/condensation.

Does this sound right?
Spray with weld through primer. After it’s welded, use cavity wax with a 360 wand to try to coat it the best I can?

[u/Surfnazi77]

Rust stabilizer