[philPKP]

Metalman ya did"nt have ya fan pointin EAST did ya? <img src="graemlins/sweat.gif" border="0" alt="[sweat]" />

[Henry Moran]

[QUOTE=henpecky]

Originally posted by Madd Syntst:
<strong>I know the trill of welding galvanized, but what about painting it? I know there is something you need to prep it with or etch it before primer. I am making a tube grill from electrical EMT </strong><hr></blockquote>

you can use a self etching primer,spies-hecker brand has a real good one,dont know if you have a spies dealer where you are,if not they are located in warren,michigan and will ship to you on cod.

You can use a paint brush and paint it with pool acid just work in a well ventilated area and wash it properly with water afterwards (use a mask) it gives
a poisonous gas off when the chemical reaction take place thereafter coat with primer. I have done gavanized sheet plates it go back to the black plate stage
before it was galvanized

[Scode68]

The upper cowl on a 68 Mustang I’m going to repaint is galvanized and the old paint is pealing. Should I strip the paint, scuff the metal and just shoot it with a self-etching primer? I have some Dupont Variprime 615S and all the tech manual says is to apply it to “Properly prepared/cleaned steel, aluminum and galvanized”.

[Bee4Me]

I use an etch primer on a true galvanized metal but the e-coat panels are just scuffed and epoxied then 2k blocking primer.
The problem with using acid such as muriatic is it strips the galvanize completely off and you end up with a piece of bare steel which will flash rust almost instantly defeating the whole purpose of using galvanized in the first place.The vinegar trick dosen't work well as it is not strong enough to actually etch the metal,it just cut's off the oil's and grease so the paint will adhere but not for long term.

[Scode68]

Originally Posted by Bee4Me

I use an etch primer on a true galvanized metal ..... The vinegar trick dosen't work well as it is not strong enough to actually etch the metal,it just cut's off the oil's and grease so the paint will adhere but not for long term.

So, maybe I should just strip the paint, clean things very good and hit it with self etch primer. You say the vinegar just cuts off the oils and grease but not for long term. What do you mean by that?

[Bee4Me]

I work in a sheet metal shop and it's been an old tale for a long time about vinigar use before paint. Galvanized need's a scratch or something to etch into it for the paint to adhere to as it's slick. Like painting chrome or polished metal. The vinigar just is not strong enough to actually etch for paint. It's a fair pre cleaner but all my experience trying it has been flaking paint after a while in the weather.We do chimney cap's,some of which have been on for 10 years,that were etch primed then painted that are still in good shape today.
I'd use an etch IF you already have it,BUT,I'd use 2 coat's of epoxy after stripping/sanding instead as it will provide better long term protection and a better base to work over.I just prefer epoxy on automotive app's as it's a long term,great base compaired to etch.

[Scode68]

Originally Posted by Bee4Me

I'd use an etch IF you already have it,BUT,I'd use 2 coat's of epoxy after stripping/sanding instead as it will provide better long term protection and a better base to work over.I just prefer epoxy on automotive app's as it's a long term,great base compaired to etch.

When you say sanding do you mean to rough up the surface or to try and remove the galvanized coating? Ford did this galvanized cowl panel prior to the assembly of the car back in 1968. I don’t understand why the upper panel was done but it should have been done to the lower panel that I don’t see any evidence of it being done.

[Bee4Me]

Use some 80-180 to clean it up with. Do not sand off the galvanized if you can keep from it.It's just a thin layer over plain steel and if you get aggressive with it,it's gone.
Another reason to use epoxy IMO as even if you sand the galv. off,it's great protection against rust. Just be SURE it's CLEANED well with a wax & grease remover THROUGHLY before any epoxy or any type primer for that matter. Use clean white rag's till there is no residue on the rag after wiping.