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Re: Cheap Substrate Heating

     >>I suspect the silicon tubing is a pretty good insulator. 
     >I do not quite agree with George saying silicon tubing
     >would be a pretty good insulator, it is rather the opposite. Assuming 
     >Silicon tubing contains mostly Silicon, it actually is a very good 
     >thermal conductor. Here are some thermal conductivities to compare 
     >(in units of W/cm*C):
     >Silicon:           1.57
     <Many things snipped>
     Actually, SILICONE is a polymer of Si, O, and an organic group (R), 
     and it looks like
           R    R    R
           |    |    |
           |    |    |
           R    R    R
     Silicones are inorganic polymers, that is, there are no carbon atoms 
     in the backbone chain. The backbone is a chain of alternating silicon 
     and oxygen atoms.  Each silicon atom has two groups attached to it, 
     and these can be any organic groups.  The most common organic group is 
     CH3, and this polymer is called polydimethylsiloxane. It is the most 
     common silicone, and I think aquarium tubing is made from this. 
     Silicones are also used to make the heat resistant tiles on the bottom 
     of the space shuttle.  Silicone is a very poor conductor of heat.
     SILICON, the element, is a very good conductor of heat, just as the 
     data Karsten provided us shows.  However, silicon and silicone are 
     completely different substances and have different properties.
     Hope this wasn't too far off topic.
     Kind regards,