Can someone tell me whats this is from?

[lyrikz]

What is this from, and how do i prevent it? I sandblasted my cab, cleaned it, and epoxyied the cab. The cab sits in the garage. I did some metal work after that, and about 3/4 months later i notice this.


That area is the left kickpanel. Thats where the floor meets the kickpanel. Only thing i can think is that its metal shavings that have rusted... I obviously cant paint over that right???

How do i prevent this? I thought epoxy didnt rust... There was NO moisture at all except for regular air moisture in a garage...