Tony Olsen on wed 25 jun 03
This one will get you there (I think)
http://www.laughingbrookpottery.com/gallery.html
Nice work Liisa!
When I ordered materials last, I clicked on Black iron ox instead of =
red. is there a direct factor for substitution or do I need to re-order =
the red?
Thanks,=20
Tony Olsen (Galveston)
Tom Buck on fri 27 jun 03
Tony O:
There two black iron oxides.... FeO and Fe3O4 (intimate mix of FeO &
Fe2O3).
the following is being typed on screen, and the calculations done in
step (so I might make a math error, please check---Fe atomic weight, is
56; O atomic weight is 16, and the subscripts say how many atoms are
in the molecule).
if your recipe calls for 10%w Fe2O3 (red ox) per kilogram, ie, 100 grams
RIO, you are placing 100/160 = 0.625 moles in the mix. But since each mole
of RIO has TWO Fe units in it, whereas FeO has ONE, you would need to use
0.625x2=1.25 moles of FeO to match the same Iron Oxide content in the
glaze. this amount of FeO is hence 72x1.25 = 90 grams black iron oxide FeO
type. for Fe3O4 type with THREE Fe units, you would use 0.67x0.625 moles =
0.42 moles Fe3O4 or 97 grams this black type. ask your dealer which black
he provided.
but as you can see, a 10% variation in Iron Oxide content will not much
affect a glaze that has a substantial amount of RIO in it.... a typical
glaze melt (alumino-silicate glass) is capable of dissolving up to 5%w of
Iron Oxide, ie, 5 grams per 100 grams of liquid melt...the rest stays as
tiny crystals (ie, solids).
til later. Peace. Tom B.
Tom Buck ) -- primary address.
"alias" or secondary address.
tel: 905-389-2339 (westend Lake Ontario, province of Ontario, Canada).
mailing address: 373 East 43rd Street, Hamilton ON L8T 3E1 Canada
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