Rust repair (restoring galvanized finish)

[DVZ]

Just wondering if anyone knows how to restore the galvanized coating once rust is removed. I found a product called Galvax made by Alvin Products (www.alvinproducts.com/Upload/PageContent/PageContent33.pdf). It is a zinc-rich cold galvanizer that is applied to stripped metal to restore rust protection. Paint is then applied over this finish.

Has anyone had any experience with this product or any other method of restoring the galvanized finish after a repair? Also, could use some suggestions on how to best remove rust (wire brush, spot glass blaster, etc...) from a small area. I have some surface rust around the battery area and would like to address this problem before it becomes more serious.

Thanks.
www.alvinproducts.com/Upload/PageContent/PageContent33.pdf

[Zeke]

Well, I jussut did a search using my name and the word "rust." That produced about 100 posts. Try it yourself and see. There is some sillyness and some good info. Lots of folks here have contributed to my knowledge and you can find just about anything you want to know on the subject with the above terms.

[Ove]

DVS,

I've had a bad experience with a zinc product. I applied it to bare metal and found that the zinc would very easily chip off the metal. After a couple months I had lots of small rust spots where the cold galvanizing had (or was about to) come off

I have lots of experience with other types of primer and paint, and this has never happened to me before.
It's many years ago, and I cannot remember the brand, but it was not "Galvax".

For this reason I recommend that you try the zinc on a piece of scrap metal first, before you use it on your car.

[Dan in Pasadena]

I have some experience with a "cold galvanizing" product from the construction industry. Obviously, not a direct correlation to automotive, but "cold galv" repair of hot dipped galvanizing used in the construction trades is really no more than a spray can of paint with a high zinc content. Sorta like medium gray primer with zinc in it. It works, kinda/sorta for minor damage to a hot dipped handrail or embedment article, but to paint over it in an automotive situation? I don't think so. Not my car. Basically I'd want the naked metal mechanically clean as I could get it, thorough wipe down with a Metal Prep type cleaner before priming properly with an etching primer. That's about as good as you can get to repair damaged facotry galvanizing. Just my $.02.

[kycarguy 935]

I have been using the zinc rich cold galvanizing products for quite a few years. The brand I use CRC Zinc-It part #18412 and it works great. Its about $7.95 for a 13 oz. can at my local nut and bolt house. I was told Lowe's and Home Depot carry it also but have not confirmed.

I have a test ongoing on a turbo flair outside in the rain and snow coated with Zinc-It and it doesn't have one spec of rust yet in 15 months. I did grind the metal with 80 grit before I applied it then wiped clean with acetone.

I also build a few hot rods and muscle cars and use this same stuff on critical areas.

[DVZ]

Thanks for the info provided so far. I followed Zeke's advice and did some surfing. The following procedures keep coming up in one form or another:

1 - Remove any loose rust with a wire brush or wheel (heat gun and scraper works best for removing sound barrier and undercoating).

2 – Degrease and clean the metal with either POK-15 Marine Clean or Wurth Clean Solve Auto Cleaner/Solvent.

3 – Etch the metal by applying either POK-15 Metal Ready or Wurth Metal Prep

4 – Seal the metal by applying either POK-15 or Wurth Rust Guard

5 – Apply body filler and sand if required

7 – Apply paint to sealed surface after the sealer is dry.

Use Silver POK-15 on badly rusted or pitted areas. Use Black POK-15 on frames, underside of fenders, etc. use Clear POK-15 as a pre-primer on exterior surfaces. I think the same rules apply to Wurth. In fact several threads stated that Wurth Rust Guard is really POK-15 sold under the Wurth name.

I am getting mixed reviews on cold galvanizing. Would be interesting to see what other experiences people have had with this method.

Also, reading the Q&A on the POK web page, it appears that POK-15 adheres better to rust. Does that mean mechanically cleaning the metal of all visible rust is a waste of time and will actually work against both POK-15 and Wurth Rust Guard?

Finally, has anyone used a spot blaster? Does it work well for cleaning small areas like corners and spot welds or is it more trouble than it’s worth?

Thanks again for everyones input.

[DVZ]

If anyone is interested here is link to the American Galvanizers Association's recommendations and list of suppliers for touch up and repair of galvanized steel.

http://www.galvanizeit.org/resources/files/AGA%20PDFs/T_TUR_01.pdf

[randywebb]

POR-15, not POK-15 -- people using a search engine won't be able to find it w/o POR15

the adhesion issue is an interesting one -- I would try to contact them thru their web site and ask

[RickM]

I've used DuPont Variprime (615S with 616S converter) self etching
Zinc Chromate primer on many projects, including my present 911, and have never had an issue with rust.

[Zeke]

Originally posted by RickM
I've used DuPont Variprime (615S with 616S converter) self etching
Zinc Chromate primer on many projects, including my present 911, and have never had an issue with rust.

amuch better product for any under finish coat paints. I would be leery of the spray can stuff under the paint. OK maybe in undercar or body cavity situations. Still, no better product than POR-15 for rust encapsulation.

I see one step missing in the above by DZV. I think putting body filler right over POR is a no no. It needs an epoxy or or polyurethane primer first. POR is too shiny and hard for body filler to stick properly.