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Tue Dec 13, 2016 2:47 pm

I have some rust behind my kitchen that i want to take care off. I would like to use zinc chromate primer; however, it hard come by locally. The only stuff i found is online; and i would like to know if this is ok to use? Link below

http://m.ebay.com/itm/361502696372?_trksid=p2141725.m3641.l6368

Tue Dec 13, 2016 2:56 pm

This looks like a better deal, and it specifies steel compatibility.

https://www.aircraftspruce.com/pages/cs/primers/zinc.php

Tue Dec 13, 2016 3:25 pm

What about POR 15 ?

Dave

Tue Dec 13, 2016 3:40 pm

POR 15 and other similar products are just a barrier that seals out moisture and rust can still form under the coating if oxygen and moisture can get in there. The zinc primers actually protects the metal even when moisture gets to the metal. The zinc acts as a sacrificial anode actively protecting the metal. Best bet is to passivate the metal with a phosphoric acid solution, coat with a suitable zinc rich primer, and then topcoat with a barrier coating such as a paint or special barrier coatings like POR 15.

Tue Dec 13, 2016 3:44 pm

[quote="dcheek"]What about POR 15?>>

Not even close to zinc chromate.
It catalyzed black paint, nothing more.

Tue Dec 13, 2016 3:49 pm

The OP suggested that there isn't any automotive paint dealers around him.
Not one body shop supply in a 10 mile area?
Where's the local body shops get their paint & primer----fly it in?

You are looking for DuPont Vari Prime, acid etch zinc chromate primer.

Tue Dec 13, 2016 3:51 pm

Like Geodude says, the zinc paints/primers offers better protection. Even when a zinc primer is scratched or otherwise compromised, it continues to offer corrosion protection. This is because the zinc is sacrificial. In areas where perfect coverage isn't possible a zinc rich primer is desired.

The zinc chromate/phosphate primers have the additional advantage of etching into the parent metal for better adhesion.

A zinc chromate/phosphate primer combined with a urethane based top coat is some of the best corrosion protection available.

If you have existing rust I suggest neutralizing it with an acid wash before coating as Geodude suggests.

Tue Dec 13, 2016 7:18 pm

Where do you live?

If you have a Home Depot, Lowes or a good hardware store nearby look for a "Cold Galvanizing" spray paint. This will be a zinc coating. It will be gray in color as opposed to the zinc chromate green. The difference will probably be what paint you can topcoat it with. Read the label on that part.
Rustoleum is one manufacturer.

Here's an Amazon link to it:
https://www.amazon.com/Rust-Oleum-7585838-Professional-Galvanizing-Compound/dp/B00106H68W

and Home Depot:
http://www.homedepot.com/p/Rust-Oleum-Professional.../100142963

Tue Dec 13, 2016 10:32 pm

Thanks everyone, i guess i wasn't looking in the right places.

Wed Dec 14, 2016 5:09 am

I wondered how the Por 15 metal prep fit into all of this but based on company information it appears it is the same as a primer ?

"POR-15® Rust Preventive Coating on any metal surface, including aluminum and shiny polished metal surfaces. Our simple process gently etches metal, creating an ideal anchor pattern for coatings such as POR-15® Rust Preventive Coating, while simultaneously leaving a zinc phosphate coating to insure chemical bonding of paint and steel. Avoid other preps that may leave harmful residues which prevent proper adhesion. After thoroughly degreasing your work piece, apply environmentally safe POR-15 Metal Prep to both neutralize any rust and etch any clean bare metal. This will allow better adhesion of POR-15® Rust Preventive Coating or any other coating"

I wondered if I should be using the metal prep and a zinc chromate primer or just metal prep and Por 15.

Always willing to learn a new trick ....

Wed Dec 14, 2016 7:07 am

I am going to need to tackle a rust problem at some point.
I came across this thread and it is most interesting.
This was in 2004, 12 years ago. What is the current thinking? Is POR-15 system the way to go?

Wed Dec 14, 2016 7:51 am

I might suggest doing lots of research on body shop forums.

You need input from people doing rust work day in and day out. As a photographer, I have learned if you want mostly-bad advice, ask a camera store. In my past experience as a custom painter, I received good advice from painters, not dealers selling supplies. Sometimes you can get great advice at dealers in either case, but the problem is you won't know until it's too late.

Best of Luck.

Wed Dec 14, 2016 8:19 am

POR-15 ( again ) is nothing more tha a pre-catalyzed enamel.

It will not acid etch into the metal, it can't be used on aluminum, or stainless to offer a good binder for fill primer prior to top coating.

Vari prime applied to properly prepared sheet metal will acid bind to the sheet metal, plus offer a zinc barrier to rust.

The POR-15 is a back yard slipshot way of getting nowhere, and to make the final topcoat of anything, that final top coat must be applied prior to the POR stuff sets up.

It's overpriced garbage, & I know of zero professional refinishing shops that have ever used the allegid miracle in a can.

It will never be or act as zinc chromate acid etch primer / sealer.

Wed Dec 14, 2016 8:32 am

"It will never be or act as zinc chromate acid etch primer / sealer."

You're right it won't. The metal etch product is supposed to do that. You missed that part.

I'll have to check out the vari prime stuff and see what its all about.

So since you are here replying, you normally put vari prime down, then the 8115 panel adhesive to do seams ?

Wed Dec 14, 2016 8:37 am

por 15 is a poor choice. i wont use the stuff, tried it once. instead zinc chromate, variprime, dp two part primer are far superior.

good luck

ps dont use eastwood rust converter either, it promotes rust.

stick with name brnad products backed buy huge chemical companies that have invested millions in R and D to make quality products.

POR and eastwood probably have a higher advertising budget than research budget!

get products from PPG, DuPont, 3M etc...... or their subsidiaries

Wed Dec 14, 2016 8:47 am

bluebus86 wrote: get products from PPG, DuPont, 3M etc...... or their subsidiaries Agree with this.

I have a longtime client and friend doing very high-end Pebble Beach restos, and can ask him if of interest. Most of his projects are on very old cars, and I can ask my brother, too, who was a career bodyman in Florida.

Wed Dec 14, 2016 8:49 am

You have to do some reading on what product does what in a professional environment, what to use when.

You asked about the seams.
8115 displaces water /moisture-- you know that--right?

When automobiles are manufactured today, is all of the sheet metal primed first, and then the panels glued on, or glued, & then primed ?

8115 should be applied to properly prepared sheet metal, allowed to cure, then primed.

I sand blast the seams, 8815 them, then scuff them, vari-prime them, scuff, fill prime them, finish sand & topcoat.

Pretty much apply zinc , primer & paint in the same order as the mfg's. do.

I use POR on nothing.
It's for brainwashed hobbiest only.

It is truely garbage.