Rust Roy use?

[atk1]

Was given a bottle with Rust Roy written on it and just want to know if anyone knows how to apply this properly? Ive been grinding and sanding a few rust spots back to metal or as far as I can.
How long do I leave it on for?
Do I sand or wipe it back once dried?
Do I use etch primer or will a primer be OK?
Is this stuff any good?

Cheers

[BusyKiwi]

you just brush it on, dries pretty quick, turns your fingers, err i mean the rust black/purple

Is it any good? personal preference, I find it's like zinc spray - dries up and cracks off. It's meant to be a rust killer but it doesn't kill it, just covers it for a while.

I'd sand it before primer.

Things like this is great to experiment with. Get 3 strips of panel steel (or old rusted bits), just prime one, rust roy and etch another and lastly rust roy and primer. Then the boring part, leave outside for six months, is like watching paint dry.
then after six months you'll see what really happens. primer isn't waterproof I'm sure someone will say, true it's not but for this is acting as a sealer plus we want it to react.
Another test is get 3 rusty bits of panel steel, (ideally pitted but no holes), clean them all up the same (wire wheel, sand paper ... doesn't have to be mint) now skim a layer of bog (normal bondo) then prime, another with new tech and prime and the last one fibre glass and prime, again, wait six months and see what happens.
I could easily tell you what happens in each case but doing it shows you.

[atk1]

Thanks Busy. 6 months? I just wanna drive my van! The spots are around the windscreen. Good learning tho, will do

[BusyKiwi]

Only way to kill rust is sand blast it (both sides), acid dip or cut it out