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Aluminized steel vs. galvanized steel for use in composting bin

I spoke with a guy who specializes in the product about aluminized steel culvert, and told him we wanted to use it for a composting bin. He said aluminized would be better than galvanized because in the process of decomposition of organic materials, tannic acid [on eBay or Amazon] is released and galvanized steel could release traces of lead, cadmium, or hexavalent chromium. According to the guy at the culvert manufacturer, with aluminized steel, aluminum oxide is what is used in the process, and that is not toxic. I'd like to confirm that, if you know the answer. I know there is some controversy at least among "natural" food producers about aluminum coming in contact with soil where food is being grown.

My question is, would or could the use of aluminized steel release anything toxic when exposed to decomposition of organic materials and the resultant substances such as tannic or other acids? I look forward to your answer. Thank you!

Jay McPherson
Hobby farmer - Myrtle Point, Oregon, USA
February 17, 2011

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The guy is overemphasizing the word trace. Trace means darn little to a point of being nonexistent.

I bet that the galvanized will last longer.

My guess is that he is thermal spraying aluminum or is plasma spraying aluminum oxide. Headers on show cars are beautiful, but oily finger prints stand out - bad!

If the price is not ridiculous,Try one. you may like it.

James Watts
- Navarre, Florida
February 18, 2011

Hi, Jay

Your body has a "trace" of plutonium in it; everything is relative. There is no subject where there is not "some controversy"; but you will find that there is far less in peer-reviewed scientific journals than in public forums on the internet :-)

But galvanized materials have been used directly for rain water collection, and as feed and water containers for livestock for a long time, and there are traces of lead, cadmium, and chromium in the soil. I have personally heard no reports that the trace amounts of metals released into the soil from galvanized composting or planting containers are a problem.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
February 21, 2011

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