will edwards on tue 19 dec 00
Hello,
It wasn't that long ago I believe Ron Roy posted a list of ingredients kn=
own
for safety. It might be archived but heres my rendition as well.
Always wear a NIOSH approved respirator and latex gloves no matter what y=
ou
are mixing. Evaluate the ease of doing things in a simple manner that wil=
l
prove effective for you. No eating and drinking and wash hands often. IF =
you
are afraid to use the materials don't use them!
Even though I am not a GURU, this is another reason we need that term. It=
speaks loudly about those who work in this chemical soup bowl we all live=
in.
Not every person wants to make glazes nor should they. It is a limited fi=
eld
that has much more to be learned from.
(Usually found in a studio where glazes are made)
Alumina (AL203) A high melter. Adds hardness, Can matte a glaze
Silica (SiO2) Glass Former
Whiting (Calcium Carbonate) CaCO3 About as safe as you can get
Chrome Oxide (Cr203) Toxin/Hazard can be used with safty measures in good=
formulations.
Cobalt Carb. (CoCO3) Toxin/Hazard - same as above.
Copper Carb. (CuCO3) Softens a glaze usually. Can be used in a good formu=
lae
with proper precautions. (They are some safe glazes with copper)
Frits 3110-3124-3134 - Usually considered safe. Contains Free SiO2. Pract=
ice
safe habits. Wear your mask as usual.
Red Iron Oxide (Fe203) Same precautions as any glaze material. Too much i=
s
always too much.
EPK - Dust Hazards
Manganese Carbonate (MnCO3) A flux. Hazard in dry form. Use normal precau=
tions
and do not breath fumes from burn-off and dry powder.
Rutile (TiO2) Fe and V205 potential in trace amnounts.
Strontium (SrCo3) Replaces barium in many cases. o.75 to 1 ratio without
getting down to micro measures. (Mole equiv)
Then add the common things like Dolomite, Wollastonite, Potash and Soda
Spars.
Using encapsulated forms of heavy metals has not proven to me yet they ar=
e
completely without some hazards. These need some additional testing data.=
(Time we sent a few in for tests)
Remember that colorant stains are not always a safe alternate for raw
compounds either. =
This don't even break the ice on what needs to be discussed and most
importantly this information is meant to help reconize some of the danger=
s,
not feed a frenzy nor answer the spectrum of questions on toxicity materi=
als.
So when doing glaze chemistry I would suggest what the experts have said =
to me
all along. Get glaze calculations software and study up on the materials =
till
you know them well. I also would think to seek advice from Monona when in=
doubt regarding a specific material where little information has been gat=
hered
since those in the field she is trained in are generally the ones who are=
first to know. (Well most times)
Find what is known as a limit factor for safty and take it to the limits =
for
testing at Alfred.
If you think you have a great base recipe try sending it off for analysis=
with
a higher percent of oxide than the recipe calls for. I would attempt to o=
ver
supply copper if the recipe called for 3% by adding an additional 1-2% an=
d see
if it can reach near the level of safty that I was looking for in the fir=
st
place. It can be revised and maximized for higher potential for holding i=
ts
own in a good limit formulation.
If you know for a fact that it will not be used for a food bearing surfac=
e
then use your own judgment. I base mine on the potential for mis-use. How=
many
kids have you heard of mis-using many common things in this day and time?=
Plenty!
William Edwards
____________________________________________________________________
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