Filler over light rust

[drgoatboy]

Sounds like a daft question but if you've done some welding on some panels and it's not got filled straight away and the bare metal has got some light surface rust is it ok to just filler over the top of the rust?
Would the moisture barrier created by the filler be enough to stop it rusting? Or is this just going to keep rusting and eventually ruin the panel?
Thanks!

[julian64]

nope if you just put filler over even light rust you are expecting it to say hello in the next couple of months

[drgoatboy]

Ok thanks. What's best to do then. Grind down then fill?

[julian64]

I tend to use a zinc based spray after cleaning the rust off

[Momentofmadness]

As above, sand it back and put some zinc primer on or you could use Kurust.