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How can you tell if a screw or nail is galvanized or zinc coated?

My daughter, who is in tenth grade has been given a science project that requires galvanized or zinc coated nails or screws. The whole project also involves, hydrogen peroxide 3%) [affil links], iodine [affil links] and a potato. She is in a charter school that is from home so the school is not supplying anything. We can't seem to locate anything in the stores that state that they are or are not of such. What I do find, in the hardware stores, are in great quantities and expense for a small school, science project.
Is there a way to tell if what I already have at home is galvanized?
Any bit of help would be greatly appreciated.

Koren Landfair
Mother of student - Salem, OR, United States
November 25, 2008

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Hi, Koren. What you are looking for is "hot-dip galvanized nails" or "roofing nails". These will be short moderately sized nails with a good sized head (not headless finishing nails). They will not be fully metallic and reflective; rather they will be gray and rough looking rather than smooth, almost as if dipped in a grayish aluminum paint. Some may look a bit drippy because they were dipped in melted zinc. I find it hard to believe that a proper hardware store would not have a small box of roofing nails for under $2.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
November 25, 2008