When working in a less than perfect garage enviroment it’s important to use the correct primer, Rustbuster Custom 421 Epoxy body primer is completely non-porus which means your vehcile can be left in primer without absorbing moisture!
https://www.rust.co.uk/…/custom-421-rust-proofing-body-prim…
It’s the body primer of choice for Matt Tomkins from Pratical Classics Morris Minor
