The V8 Owners Forum -

scuse my ignorance but if you are painting bare metal and you use an etch primer can you just paint straight onto it or does it need rubbing down first?

No, the etch is just to get a bite onto the metal with it's acid content. Then normal primer/s over that, then topcoats. You sand the primers that come after the etch, if you want to, e.g. bodywork etc.
That is, unless you're using one of these thick "high build" etches that seem to be about.

JJ, I think painting is the best example I can think of where the more time you spend doing it (and the prep), the better the result. The more layers (up to a point and depending on the paints used) and the more flatting back etc between coats will give you a better finish, though a new coat of paint will almost always look good until you get up close where you can see the difference!

My mazda was red, all I did was flat it back with some sponge backed sanding pads, clean the dust and any grease off and spray satin black straight over the top, 2 coats. The finish looks fine from a distance but isn't great up close, but it was the exact finish I was after (no bullsh1t ) I wanted almost rat look but without going full on. I have no worries about scratches etc now which makes it worry free

thats the dream a decent motor that you can leave outside tesco

thanks guys, the metal I am on about is my chassis tubing so it doesn't have to be 100%. I have got some U-pol etch and I am considering hammerite on top of that, just want it to resist the dreaded rust bug - after all it is a carlton!
BTW I am going to be using rattle cans

You probably could go straight over- but is there any point using etch primer on mild steel? I've never been impressed by hammerite but you are supposed to go straight onto bare metal with it, personally I would use grey oxide as a primer and colour on top of that. We use red and grey oxide at work every day and both stick to steel very well, red seems better but you need to put more paint over the top to get a good colour.

Save the Hammerite for a gate or something...
Etch is fine over steel, it's exactly what it's meant for. You could go etch then a topcoat, but don't use Hammersh*te.
Red oxide is pretty decent too, it takes an age to go off properly though.

Rustoleum do some good gear apparently. Other than that I've not much idea, I'd spray 2k topcoat myself, not clued up on brushing paints. There's paints like the classic chassis black of course which is tried & tested, and Tractol and other enamels.

Coming back to this. Sorry. may have had a beer...

Red oxide + chassis black, good honest tried tested system. Jenolite first to kill rust. All brushable.

Etch primer + topcoat of choice - etch is good, will kill micro rust. That said, rattle can etch probably isn't as good as 2-pack etch.

Epoxymastic is supposed to be top chassis stuff. Bilt Hamber make it I think.

Just to confuse things even more, I like to use Zinc primer on chassis. Not the davids stuff cos its crap but proper industrial stuff like galvafroid or crown. Obviously its no where near as good as proper galvanising but it does work. Especially useful on something like a chassis where it is getting hit with stones and isn't inspected/repaired very often. Put it onto the bare metal as a base. Not for race use as it adds a bit of weight but for a street car where a couple of extra KG doesnt matter it will add years to the life of the chassis.

JJMclure wrote:thanks guys, the metal I am on about is my chassis tubing so it doesn't have to be 100%. I have got some U-pol etch and I am considering hammerite on top of that, just want it to resist the dreaded rust bug - after all it is a carlton!
BTW I am going to be using rattle cans

Hammerite is a con. Use a proper chassis paint.

thanks guys, anyone know if etch is porous? I thought normal primer was but not sure about etch

etch is a surface conditioner that has a temporary effect dependant on humidity etc etc. If it's not primed within a certain time, you need to redo it and carry on from there.

If you want to leave inside doors etc with a primer finish, then blast it with clear coat to seal it as water WILL penetrate it.