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<div class="moz-cite-prefix">Stovers,<br>
<br>
I think that Hugh is not on the Stoves Listserv and cannot post
messages. So I am forwarding his reply to all of you.<br>
<br>
In response to Boston's comment, he is correct about the parts of
the stoves that are NOT in the direct pyrolysis and combustion
pathways. The galvanizing will remain intact if surfaces are
under 200 C.<br>
<br>
Thanks to all for the responses.<br>
<br>
Paul<br>
<pre class="moz-signature" cols="72">Paul S. Anderson, PhD aka "Dr TLUD"
Email: <a class="moz-txt-link-abbreviated" href="mailto:psanders@ilstu.edu">psanders@ilstu.edu</a> Skype: paultlud Phone: +1-309-452-7072
Website: <a class="moz-txt-link-abbreviated" href="http://www.drtlud.com">www.drtlud.com</a></pre>
On 2/1/2013 2:08 PM, Hugh McLaughlin wrote:<br>
</div>
<blockquote
cite="mid:1359749280.99710.YahooMailNeo@web84511.mail.ne1.yahoo.com"
type="cite">
<div style="color:#000; background-color:#fff; font-family:arial,
helvetica, sans-serif;font-size:12pt">My perspective on this is
it takes real stupidity to be harmed by galvanized stove parts.<br>
<br>
The core concern is arc welding galvanized material - which
vaporizes the zinc metal rapidly enough that it does not oxidize
to zinc oxide. Then you have to breath in the zinc-laded smoke -
again rather easy to avoid. The same effect happen in spot
welding, but in smaller quantities.<br>
<br>
If you are exposed, you get a flu-like response. See
<a class="moz-txt-link-freetext" href="http://en.wikipedia.org/wiki/Metal_fume_fever">http://en.wikipedia.org/wiki/Metal_fume_fever</a><br>
<br>
The real issue is processes that deal with molten zinc, such as
when casting zinc. But even then, the risks of burns outweighs
the zinc inhalation concern.<br>
<br>
For stoves, a slow heating of the galvanized surface in the
presence of air will oxidize the surface and render it less
scary. However, it should be noted, that if you lick the zinc
oxide off the ductwork, you will get the same metabolic effect.<br>
<br>
I recommend the same precaution for galvanized materials as I do
for any painted materials or recycled tin cans - burn the
completed unit first time outside in a well ventilated area -
and avoid sucking up excess smoke. Your lungs will tell you when
something is disagreeable, and react accordingly.<br>
<div><span><br>
</span></div>
<div>Hugh McLaughlin, PE<br>
</div>
<div style="font-family: arial, helvetica, sans-serif;
font-size: 12pt;">
<div style="font-family: times new roman, new york, times,
serif; font-size: 12pt;">
<div dir="ltr"> <font size="2" face="Arial">
<hr size="1"> <b><span style="font-weight:bold;">From:</span></b>
Paul Anderson <a class="moz-txt-link-rfc2396E" href="mailto:psanders@ilstu.edu"><psanders@ilstu.edu></a><br>
<b><span style="font-weight: bold;">To:</span></b>
Discussion of biomass cooking stoves
<a class="moz-txt-link-rfc2396E" href="mailto:stoves@lists.bioenergylists.org"><stoves@lists.bioenergylists.org></a> <br>
<b><span style="font-weight: bold;">Sent:</span></b>
Friday, February 1, 2013 2:38 PM<br>
<b><span style="font-weight: bold;">Subject:</span></b>
At what temperature are the bad gases from zinc created,
vs harmless zinc oxide?<br>
</font> </div>
<br>
Stovers,<br>
<br>
Galvanized metal in stoves gets mentioned occasionally. Do
we have a clear answer about what is the temperature at
which the zinc makes poisonous gases (such as when welding)
versus making zinc oxide (the white stuff that you can by in
a tube to put on your nose to prevent sunburn)? Is it bad
if the temperature is at 400 C to 700 C? Or does it need to
get much higher?<br>
<br>
Paul<br>
<br>
-- Paul S. Anderson, PhD aka "Dr TLUD"<br>
Email: <a moz-do-not-send="true"
ymailto="mailto:psanders@ilstu.edu"
href="mailto:psanders@ilstu.edu">psanders@ilstu.edu</a>
Skype: paultlud Phone: +1-309-452-7072<br>
Website: <a moz-do-not-send="true" target="_blank"
href="http://www.drtlud.com/">www.drtlud.com</a><br>
<br>
<br>
<br>
</div>
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