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Re: cold applied galv.

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            Mike,

                        In addition to what the others have said, we use ZRC (trade name) a lot. We’re often required to hot-dip our embeds, then touch up the welds that burn through the zinc. We do not see the point: if the most highly stressed portion of the connection, the weld, has just a zinc-rich paint, then why not put zinc-rich paint on everything. Well, I think a lot of the reason is the pickling: a hot-dip galvanizer prepares the surface, cleaning a lot off. Hot-dipped embeds start to rust after maybe 5 years. When we do put zinc-rich paint on an entire embed, the embed starts to rust in less time, maybe 2-3 years, despite their salt fog test reports. I think if we pickled those embeds first, the time to rust would be about the same. If you tell your contractor to clean his breadboxes first, he might just hot-dip. Of course, his paint shop may have a blast room, and provide an SSPC (http://www.sspc.org/ ) commercial cleaning or better first.

            Jim Getaz

            Precast Concrete Engineer

            Winchester, Virginia