Dads painted that rust killer stuff on my car, now what?

[bigfatnick]

hi all.

I started fixing the rust on the arches yesterday morning, i'd cleaned all the filth out of the channel behind the arch, removed all the paint and wirebrushed the rust down a bit. then the phone rang and i had to go out.

my plan was to get the wire brush attatchment on the drill and bring it back to bare metal then (possibly skim fill it), prime/paint)

only when i got back i found he'd painted that rust killer stuff all over it. he says he did as i was going to do and couldnt actually get it back to bare, shiney metal, which sounds a bit dodgy, apparently he put the rust killer on "black metal". Anyway, whats dones done. i just want to know what to do now.

i presume, its case of skim it with filler, prime and paint it. but how many coats of rust killer does it need? should i even try remove what has been done?

thanks,

nick

[Nightmare]

nope - sounds like he has done fine (as long as the bits have been removed) all you're trying to do is make sure that the oxidising metal has been fully done (which is basically what the rust stop does) - hence it going black.
you cant over apply it though, but another coat is unlikely to help as long as all visible bits were got with the first coat (photos would help advice). only risk is if there was quite a thickness of rusting metal left anywhere which you then only stop the top coat on - cos it'll come back in a few months.

next...as you say fill, sand, prime, paint.

the first two steps being key to getting a good finish. prep is boring but DONT skimp on it. A great paint job on a poor surface looks far worse than a shonky paint job on a well prepared surface!

[bigfatnick]

cheers mate, dont worry, i've got plenty of time to prep it well, i'm only doing it because i'm say at home with a broken arm!

someone suggested i should try rub back the black stuff a bit, would you say yes or no to that?


thanks

[Nightmare]

only enough to 'key' the surface to make sure the filler grips properly......you dont want to expose any metal (and if you do bung more rust stop on it!) just roughen it a bit with some coarseish wet n dry.

(this is all assuming that all and any loose bits have been removed of course)

[bigfatnick]

thanks mate, most helpfull!

[GreenV8S]

Make sure the rust killer has been cleaned off thoroughly before you start. Read the instructions, but it normally needs washing off, don't just let it dry.

[bigfatnick]

thanks mate, thats kinda the sort of infomation i was after. as you can imagine, the instructions were thrown away before my dad blathered it all over my car (very unlike him, but heyho).

This is kinda why i put this post up (should have made that clear beforehand, sorry!)

[hugodc]

some rust killers are meant to be painted over

[GreenV8S]

hugodc said:

some rust killers are meant to be painted over

The ones I've had experience of have been acid based (mainly phosphoric acid which converts the rust to a stable form of iron phosphate). You can paint over the iron phosphate, but you have to wash the excess acid off first.

[bigfatnick]

thanks guys, i'll slosh on another coat, give it a wash first before i do anything with it then!