It is important to prepare the surface if you expect long life. Wire brush
all surfaces with a cup brush on a angle grinder. Wipe down the surfaces
with a clean rag and paint thinner. Brush on at least two coats following
the instructions on the can. Brushing will always ensure a better bond with
standard enamels because you are stirring the paint onto the surface. When
you spray the paint lands on top of the metal or dirt and you hope it bonds.
The thicker the paint film the better generally so multiple coats are better
than one thick coat. Slow drying oil base paints are better than fast
drying.
On metal parts break all sharp corners with a grinder. A sharp edge does
not hold the paint film so you end up with a very thin layer of paint.
Moisture gets under the paint at the edges and corrosion lifts the paint
film off.
That's is all I can think of. Most people like to blame the paint but any
good paint job is in the preparation. Rustoleum is a good brand but you
will not get as durable finish with a spray can as with a can of Rustoleum
brushed on.
Randy

"Alex" wrote in message
. ..
Is RustOleum any good for long term rust prevention?
I just got a can of primer and paint of it from HomeDepot but want to hear
if anyone had
a bad experience with it.
I am going to use it to paint bare metal parts of my new metal grinder. I
live near the
Pacific Ocean so rust is a big problem here.

Thanks