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soda ash/bicarb (fwd)

updated fri 12 nov 99


Tom Buck on thu 11 nov 99

Some have asked about the volatility of soda salts in an electric kiln. So
I checked on it and sent this earlier (to Dannon R):

You have to go to nearly C10 (1275 oC, 2330 oF, actually) before sodium
oxide, Na2O, vapourizes ("sublimes"). So in a C6 firing (max 1230 oC, 2250
oF) there will be some Na2O vapour in the kiln environment but not likely
enough to damage elements. After all, you do not put much Na2CO3 (or
NaHCO3) on the pot, and most of what is there as Na2O links to clay
molecules, forming a glaze.

I'd say worry about some other problems, not soda attacking Kanthal A-1
Incidentally, in my last C6 glost, I coated a few pots (light
salmon coloured burning) with Na2CO3 solution, and yes indeed the "toasty"
colour did appear. So, "soda glazing" is feasible in an electric...used
Good pots BFN. Peace. Tom B.

Tom Buck )
tel: 905-389-2339 >(westend Lake Ontario, province of Ontario, Canada).
>mailing address: 373 East 43rd Street, > Hamilton ON L8T 3E1 Canada > >On