Hi, I have some ancillary parts that were corroded. I've removed the corrosion, sanded with 180grit and sprayed them with 2 coats of an aerosol Etch Primer (UPol #8) and let them dry over night.

Now they are dry I want to apply an enamel gloss black which I'll spray using a spray gun.

Do I need to key the etch primers surface with sand paper, or is it safe or spray straight onto the dry primer?

Thanks in advance

I don';t know about shaker can stuff, but you usually have a recoat time that you can spray over it without haveing to sand, like 12 hours or something like that. just to be safe with your shaker can material i would lightly sand with something fine for enamel 500 or so. ideal would probably be a scotch brite pad. usually etch primer is used as a binder for dirty metal like with some flash rust or brown rust stains it also improves adhesion some. if i'm going to use it i plan on coating it shortly with a sandable primer of some kind. no sanding between required. I just reread your post. if you want a good gloss finish you should shoot some sandable primer on. i don't think your going to get much filling with the etch prim the sandable primer would give you something to fill with and sand smooth. just an idea, its up to you black shows everything.
Jay D.

Thanks for the reply.

To be honest the quality of the finish is not that important. The paint in this case is just a coating to protect the metal from rust for the most part.

What I don't want is for the enamel paint to start flaking off after a year or two because I've not given the primer a key.

Self explanatory.

I am going to take that as a "no" I don't need to sand.

Thanks

I always thought Etch Primers needed to be covered with a Regular primer following application of Etch over bare steel to lock it down and Protect the Base coat from the Etch acid. ????

Body shops use etch all the time and paint right over it.
It's pretty standard.

I could have sworn the ones I looked at required a 2K primmer over them in the Tech sheet.
Never used the stuff my self I remember ODG was a Big advocate of the stuff.

I don't use etch primer either, but there's nothing wrong with it,
it just gets passed over because of all the epoxy hype.
Body shops don't usually use epoxy, mostly use etch and have been using etch
before epoxy primer was even thought of.
I stripped my aluminum boat with paint stripper that originally had etch primer on it,
and epoxy primer on it from a later painting, the epoxy came off easily,
the etch didn't even soften, I had to sand it off.
Toughest stuff I ever tried to use stripper on.