[Homeroast] On Topic: Popper-Roasting

John Nanci john at chocolatealchemy.com
Fri Jul 12 10:58:08 CDT 2013


So far, in about 15 years of playing with nichrome, what I have found 
is that in theory, that is true, but in practice the element just 
burns out and breaks.  For very heavy nichrome in non-corrosive 
atmospheres like a kiln (per your reference) it has a better chance 
of being true but in roasting applications, where the wire is thin 
they just burn through quickly.

John

At 03:59 PM 7/11/2013, you wrote:
>On Thu, Jul 11, 2013 at 08:28:17AM -0700, John Nanci wrote:
> > To my knowledge, nichrome (or any resistive heater) does not 'tire
> > out' to any noticeable degree.  They fail, but that's it.  So you
> > can take that off the table.
>
>     The resistance of the elements will increase with age, due to the
>     reduction in cross section by oxidation, and also, due to
>     elongation of the loops.  This will result in decreased power
>
>     http://www.nationalelement.com/hottips.cfm?TipID=6
>
>Of course, many of the same things that cause this aging also
>contribute to the eventual failure.  I was hoping to find confirmation
>of the longstanding impression I have that, in the sort of wire-coil
>heaters we're talking about here, there wasn't usually a whole lot of
>increase before they would check out.  OTOH, especially when talking
>about a popper that's working well up to some roast level but then
>struggles (and maybe fails) to go further, small changes in the roast
>chamber inlet temperature can make a surprising difference.
>
>--
>Happy Holidays!  Cry "Charge it!" and let slip the dogs of more.
>
>
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