SOURCE
https://www.eng-tips.com/viewthread.cfm?qid=246758
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QUESTION
This is a standard problem and there is probably a solution somewhere
You have hot dipped galvanized a part and shipped it. It is then supposed to be welded to another hot-dipped galvanized part.
The welding messes up the protective coating specified.
How do you go around this problem? Do zinc based metallic looking paints do the job?
REPLIES
HgTX
Galvanized coating should be removed before welding.
For repair to the coating, there are three options I can think of, in what I think is descending order of cost. You get what you pay for.
- Metallizing
- Solder rods
- Paint (“cold galvanizing”).
With the paint, you want to make sure that it will provide a dry film with minimum 94% zinc content. Beware–often you will find a zinc % on the can that is not the zinc content of the paint but rather the purity of the zinc dust ingredient. (Kind of like “contains 100% pure aloe vera!” where aloe vera is only the 3rd ingredient in the goo.)