Chris Stanley on thu 25 aug 05
If some one ever finds the lyrics to "Stinky Clay Water Is Your Friend"
(David)
This could be number two on the instructional Album.
WE could call this the "Vitrification Song"
In the tune of "Grandma just got run over by a reindeer" "My Pot just
exploded in the Microwave"
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG]On Behalf Of John
Hesselberth
Sent: Thursday, August 25, 2005 6:20 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: POT EXPLODED IN MICROWAVE!
On Aug 24, 2005, at 9:04 PM, Paul B wrote:
> My mom put some butter in a bowl i gave here and put it in a microwave
> to
> melt it for about a minute and it exploded! The bowl had a glaze with
> 10%
> RIO lining the inside and part of the outside. I know you are not
> supposed
> to put metal in microwaves and i wonder if that was the cause? I don't
> see
> how the body could be at fault since it has been used with so many
> baking
> items.
> Anyone out there have an opinion?
> thanks,
> Paul
Hi Paul,
Your pot 'exploded' because the clay was not vitrified and had absorbed
enough water through dishwashing or whatever to cause the problem. Iron
in a glaze does not cause this problem. I and others have tested up to
15% iron oxide in a glaze on a well vitrified body and not seen any
unusual heating in a microwave.
If you will check the absorption of your fired clay body you will
probably find that it is above 3%. A body like this can survive oven
heating because it is much slower than microwave heating. You need to
fire that body to a higher cone or get a body that will vitrify at
whatever cone you are firing to. You don't say where you are firing,
but if you are working with earthenware you need to switch to stoneware
to keep it from happening.
Regards,
John
John Hesselberth
http://www.frogpondpottery.com
http://www.masteringglazes.com
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