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JBaymore

Member Since 06 Apr 2010
Offline Last Active Today, 10:14 PM
*****

Posts I've Made

In Topic: What Does Slow Cooling A Kiln Get You?

26 April 2016 - 09:20 AM

Most of the visual effects that people see with large gas kilns that they attribute to "reduction" actually come from the typically slower cooling profiles that stem from the better insulated, lower surface area to volume ratio, larger thermal mass which such kilns tend to have.  Not the reduction reactions.  Small kilns (like the typical studio potter electrics) tend to cool off at the upper reaches of the firing range very quickly.

 

If you are wanting gloss glazes......... cool quickly.  If you want more varigation of the surface, semi to matte surfaces... slow the cooling.   

 

As has been said above... not all glazes will be impacted by slower cooling.  But al lot are.  What you are getting is microcrystalline crystals floating on the surface of the glaze.  A lot of glazes have the right combination of oxides present in the correct amounts to facilitate this effect.

 

Don't think of a "firing profile" as going from room temperature up to peak... and then magically "done".  Think of it more like from room temperature up to peak and then down to room temperature.  It is a paradigm shift. 

 

Computerized controllers have made "firing down' easy.

 

best,

 

.....................john


In Topic: Simple Wadding For Supporting Pots In Electric Kiln Glaze Firing

23 April 2016 - 07:41 AM

I think you are maybe mis-reading the above posting.

 

One particular wadding mix is 50% alumina hydrate and 50% EPK.  Does that help?

 

It is not 50% EPK wadding MIX that is half of the recipe.

 

best,

 

...................john


In Topic: Zinc Oxide

22 April 2016 - 12:50 PM

 

Unless someone using the pottery on a consistent basis has hemochromatosis then the iron isn’t an issue.

 

Nice pickup on that one, Min.  :)

 

Copper is generally not much of an issue either (but is a great visual 'marker' for potential leaching)... except to people with Wilson's Disease.  (It can alter taste of foods though.)

 

best,

 

...................john


In Topic: Digitalfire

22 April 2016 - 10:55 AM

Check your SPAM filter.  It might have been blocked.

 

It is likely that an account was auto-created based on your email address.  That is maybe why it said you had an account already.  I think it auto sends out and email with a code to verify your account and then change the user details and password and such.

 

 

 

best,

 

................john


In Topic: Digitalfire

22 April 2016 - 09:42 AM

Here:  https://insight-live.../signup.php?SID

 

best,

 

.................john