gEDA-user: hotplate engineering

[John Griessen <john@xxxxxxxxxxxxxx>]

DJ Delorie wrote:
>> How about an aluminimum plate on top of the hot plate.  3/8" would  
>> distribute the heat pretty well and costless than the fancy hotplate
> 
> If I did that, first I'd bring the plate to a machinist friend and
> remove as much of its existing thermal mass as I could.  It's already
> got more thermal carry-over than I'd like.


For heavy mass, (more wasted power), hotplates are buyable easily -- just
go for old ones from the 1930's to 1950's.

Here's an idea borrowed from IR soldering equipment:  Buy metal film resistance heaters
that connect with a welded tab that is left near a heat sink to outside, so it doesn't get as hot.
For IR heating, assemble with a quartz glass side, for your app assemble with two aluminum plates
and a small amount of insulation on one side, (mica), and plenty of glass fiber on the other.

Then you have a low mass, even heat plate.  If your design heats up the connections between resistive elements and
conductors, they will always degrade, oxidize, and eventually fail.

John Griessen
-- 
Ecosensory   Austin TX


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