Snail Scott on sat 23 apr 11
On Apr 23, 2011, at 8:57 AM, Dan Parenteau wrote:
> The objections raised were that firing wet, or not completely dried,
> glaze chemicals might result in all kinds of explosive havoc in the kiln.
I seldom fire glaze waste, as few of the materials
I use are hazardous if dumped on the ground.
However, it works just fine if you have materials
of concern. Dry it well, and it will fuse at the
temperature of the glaze. Very thick depths of it
will result in crazed lumps of glaze, but if it was
a stable glaze, it should still be stable, in terms of
non-release of materials. There is no real reason
to fear explosion if you candle appropriately for
a thick mass. Better yet, put the stuff in the bowl
for firing AFTER it's dried out. You will merely
have lots of small dry lumps, not a solid mass
capable of trapping explosive moisture.
-Snail
Michael Wendt on sat 23 apr 11
Dan,
Unless the toxic chemicals are lead or cadmium, you can
safely dispose of the dry glaze in ordinary trash.
Why?
I checked the EPA web site and there are upper limit values
for things like barium and copper in drinking water around 1
part per million. If you check the solubility product
constant for the common glaze materials, you will find they
are mostly insoluble (some like cobalt sulfate are water
soluble though so be sure to check), so dumping them unfired
on the lawn or in an ordinary dump site poses no risk of
ground water contamination.
I think it is wonderful to be careful rather than just
dumping.
Regards,
Michael Wendt
Dan Parenteau on sat 23 apr 11
I am a member of the Madison Potters Guild here in Wisconsin and last
night we were discussing studio maintenance. In the past we have
shoveled the glaze slop/solids into bags and thrown it away. One of our
new members had read an article which suggested periodically firing the
slop in bisqued bowls to solidify/vitrify it and so greatly reduce the
chances of the chemicals making back into the environment when they are
thrown away. Does anyone know which article or publication that was?
I am looking for potters or studio technicians who perform this
procedure in their studios to please respond as to how you do it and
what, if any, problems you have encountered.
The objections raised were that firing wet, or not completely dried,
glaze chemicals might result in all kinds of explosive havoc in the kiln.
Without meaning any offense, if your response is to stop using hazardous
chemicals entirely, or that we should use our slops as a mystery glaze,
please refrain from replying. :)
Thanks!
Dan Parenteau
David Beumee on sat 23 apr 11
Hi Dan,
For the particular glaze slops/clay slurry that settle out in my clay tra=
p
under the studio sink, I am mixing it with a large jiffy mixer, adding wate=
r
to make a reasonable glaze slop, screening through an eighty mesh, and then
have used a test tile to test as a glaze, usually about a 6 count dip. The
result from my cone 10 reduction kiln has consistently been an unattractive
shiny gray/greenish mottled glaze with lots of iron spots that breaks nicel=
y
over texture. I can tell from the way this clay catch slop glaze stays in
suspension and the non running of the result that it has plenty of clay in
it, making it very easy to use. The next step for my taste is to ball mill
the glaze for an hour or two to reduce the iron spots, and I do a triaxial
blend with various other materials in the studio to get a better color
result. The result is an original glaze from my studio and my clay trap, an=
d
no more dumped dried out clay trap in the landfill.
David Beumee
Porcelain by David Beumee
806 East Baseline Road
Lafayette, CO 80026
www.davidbeumee.com
303-665-6925
On Sat, Apr 23, 2011 at 7:57 AM, Dan Parenteau wrote:
> I am a member of the Madison Potters Guild here in Wisconsin and last
> night we were discussing studio maintenance. In the past we have
> shoveled the glaze slop/solids into bags and thrown it away. One of our
> new members had read an article which suggested periodically firing the
> slop in bisqued bowls to solidify/vitrify it and so greatly reduce the
> chances of the chemicals making back into the environment when they are
> thrown away. Does anyone know which article or publication that was?
>
> I am looking for potters or studio technicians who perform this
> procedure in their studios to please respond as to how you do it and
> what, if any, problems you have encountered.
>
> The objections raised were that firing wet, or not completely dried,
> glaze chemicals might result in all kinds of explosive havoc in the kiln.
>
> Without meaning any offense, if your response is to stop using hazardous
> chemicals entirely, or that we should use our slops as a mystery glaze,
> please refrain from replying. :)
>
> Thanks!
>
> Dan Parenteau
>
--
John Hesselberth on sun 24 apr 11
> On Apr 23, 2011, at 8:57 AM, Dan Parenteau wrote:
>> The objections raised were that firing wet, or not completely dried,
>> glaze chemicals might result in all kinds of explosive havoc in the =3D
kiln.
I'm not sure David Hendley is monitoring Clayart regularly at the moment =
=3D
so I will repeat his preferred method for using Glaze slop waste. It is =3D
the best I can remember seeing. He mixes it into his clay body at 1-2%. =3D
He says you will never see it, even in a white body. Of course you ought =
=3D
to check that for yourself with your body and you glaze waste.
I think the biggest issue with firing it in bisque bowls is that the =3D
bowls themselves can crack leaving you with a glob of glaze on your =3D
shelf. I had this happen the one time I tried it.
Regards,
John=3D
Edouard Bastarache on sun 24 apr 11
Hell all,
I make 200 gram glaze tests and put 3 together to make new glaze tests.
I also put together glaze left-overs from glazing in a large pail, I then
mix them to make 4 liter samples to be tested.
You could be amazed at the results
Gis,
Edouard Bastarache
Spertesperantisto
Sorel-Tracy
Quebec
http://www.flickr.com/photos/30058682@N00/
http://edouardbastarache.blogspot.com/
http://www.facebook.com/edouard.bastarache
http://blogsalbertbastarache.blogspot.com/
----- Original Message -----
From: "John Hesselberth"
To:
Sent: Sunday, April 24, 2011 11:08 AM
Subject: Re: Firing Glaze Slop
> On Apr 23, 2011, at 8:57 AM, Dan Parenteau wrote:
>> The objections raised were that firing wet, or not completely dried,
>> glaze chemicals might result in all kinds of explosive havoc in the kiln=
.
I'm not sure David Hendley is monitoring Clayart regularly at the moment so
I will repeat his preferred method for using Glaze slop waste. It is the
best I can remember seeing. He mixes it into his clay body at 1-2%. He says
you will never see it, even in a white body. Of course you ought to check
that for yourself with your body and you glaze waste.
I think the biggest issue with firing it in bisque bowls is that the bowls
themselves can crack leaving you with a glob of glaze on your shelf. I had
this happen the one time I tried it.
Regards,
John
Paul Lewing on sun 24 apr 11
On Apr 23, 2011, at 6:16 PM, Michael Wendt wrote:
I checked the EPA web site and there are upper limit values
for things like barium and copper in drinking water around 1
part per million.
Those water standards tend to be not based on what will hurt you, but
rather what you can taste in the water. The truth is that no one
knows whether stuff like barium or copper from glazes would hurt you.
The tests have just not been done for anything but lead and cadmium,
which is why there are standards for them and no other elements. And
those tests will probably never b done, because it would be unethical
to knowingly expose people to the levels required to test. Animals,
yes, but people no.
I've said it every time this subject of disposing of glazes comes up
and I'll say it again. Don't dispose of it at all. Use it. Unless
you're making a whole lot of glaze tests of a particular composition,
your scrap glaze will be remarkably consistent over many years. You
can't make it lighter, but you can always make it darker. There is no
need for you to ever mix a black glaze. Just add colorant to your
scrap. I add 1% each iron and manganese plus 0.5% cobalt and chrome
and get exactly the same black year after year.
Or mix it with other glazes. Try mixing it half and half with an
opaque white (makes almost a celadon for me), or a clear. Then try
coloring that. I use a clear/scrap with a tiny bit of cobalt and 3%
copper to get a lovely dark green at cone 4 in oxidation. If you use
any chrome at all, add some tin to your scrap. You'll probably get
pink. Load it up with titanium or rutile or wood ash or local clay.
Just don't waste it on the lawn.
Paul Lewing
www.paullewingtile.com
www.paullewingart.com
David Hendley on sun 24 apr 11
Yes John, I was tempted to reply to Dan, but was dissuaded when he wrote:
> Without meaning any offense, if your response is to stop using hazardous
> chemicals entirely, or that we should use our slops as a mystery glaze,
> please refrain from replying. :)
It sounded like he wasn't interested in other solutions for disposing of
unwanted
glazes, so I didn't respond.
Of course, to my ultra-practical and frugal mind, using more materials (cla=
y
to make a bowl) and fuel (to bisque fire the bowl and then to fire the bowl
and the glaze), so you can throw away the whole mess, is off-the-charts
silly.
It's wasting time, effort, and materials, so you can transfer the problem t=
o
someone else. Although their hearts are in the right place, some of the
things
people do for 'ecology' leave me shaking my head.
As Mel mentioned today, many glazes are composed of minerals that are
benign and can be safely simply incorporated into the earth (Don't just
pour glazes on your grass or garden, mix the glaze into the soil). It is
routine
around here to add alkaline to the acid soil, so glazes are great soil
additives.
I'm not suggesting or recommending it, but people buy and apply to
their gardens 'trace elements' that are called 'hazardous chemicals' when
they are in glazes.
For glazes with heavy metals that you don't care to put in your soil, the
best way to dispose of them is to simply add a cup or two of glaze to
your clay the next time you make or reclaim clay. Heck, all of the
predominate ingredients in a glaze are already added to claybodies,
such as feldspar, silica, and CLAY. The small percentages of other
ingredients will have absolutely no effect on the claybody because the
percentages are too low to even matter. Even a cup of iron saturate
glaze added to a hundred pounds of porcelain is not noticeable.
David Hendley
david@farmpots.com
http://www.farmpots.com
http://www.thewahooligans.com
----- Original Message -----
> On Apr 23, 2011, at 8:57 AM, Dan Parenteau wrote:
>> The objections raised were that firing wet, or not completely dried,
>> glaze chemicals might result in all kinds of explosive havoc in the kiln=
.
I'm not sure David Hendley is monitoring Clayart regularly at the moment so
I will repeat his preferred method for using Glaze slop waste. It is the
best I can remember seeing. He mixes it into his clay body at 1-2%. He says
you will never see it, even in a white body. Of course you ought to check
that for yourself with your body and you glaze waste.
I think the biggest issue with firing it in bisque bowls is that the bowls
themselves can crack leaving you with a glob of glaze on your shelf. I had
this happen the one time I tried it.
Regards,
John=3D
jonathan byler on sun 24 apr 11
I will second this. I thought I was going to save the world at one
point and decided to fire our glaze slop in bowls/vases. if they
didn't find a way to leak on firing, they tended to crack and break on
cooling leaving large pieces of extremely sharp glass to clean up. I
shortly thereafter read through all of the university mandates and EPA
stuff and discovered that everything we use can be dumped down the
drain anyway in the quantities that we use. I still don't go dumping
the stuff down the drain, but I am less concerned about disposing of
the stuff since reading these publications. we don't use anything
that the university considers hazardous, like lead or barium, so our
waste stream is clean as far as that is concerned.
If we were to use barium or lead in glazes I would want to separate
them out into an entirely different waste stream to simplify disposal
and reduce the amount of "contaminated" materials to dispose of with
our hazardous waste people.
anyway, long story short, the firing of our ordinary glaze materials
into hard lumps of glass seemed in the end to be a waste of time,
energy (gas and electricity are not free!), and effort on my part.
This is especially since the vast majority of the material we have
left over is clay, feldspar, and iron oxide, with varying small
amounts of other materials that don't need to be disposed of as
hazardous waste. we collect the stuff up and make glaze with it again
for the most part - not what you wanted to hear, dan - but it works
for us. sometimes it comes out with interesting and even good
results. you might want to do a cost/benefit analysis of what it
costs to you and the environment to fire this stuff vs. dumping it
with the trash or even out in the garden somewhere as Mel likes to do.
On Apr 24, 2011, at 10:08 AM, John Hesselberth wrote:
>
>
> I think the biggest issue with firing it in bisque bowls is that the
> bowls themselves can crack leaving you with a glob of glaze on your
> shelf. I had this happen the one time I tried it.
>
> Regards,
>
> John
Steve Mills on mon 25 apr 11
In my workshop application of glaze is carefully monitored, and left-overs =
r=3D
eturned to the bucket. Liquid waste went into the sink and thence into the =
w=3D
aste trap, and eventually into landfill
I used to try firing samples from that to see what happened, but it always =
c=3D
ame out "unfortunate" brown so I gave up!
Steve M
Steve Mills
Bath
UK
www.mudslinger.me.uk
Sent from my Ipod touch
On 25 Apr 2011, at 02:55, jonathan byler wrote:
> I will second this. I thought I was going to save the world at one
> point and decided to fire our glaze slop in bowls/vases. if they
> didn't find a way to leak on firing, they tended to crack and break on
> cooling leaving large pieces of extremely sharp glass to clean up. I
> shortly thereafter read through all of the university mandates and EPA
> stuff and discovered that everything we use can be dumped down the
> drain anyway in the quantities that we use. I still don't go dumping
> the stuff down the drain, but I am less concerned about disposing of
> the stuff since reading these publications. we don't use anything
> that the university considers hazardous, like lead or barium, so our
> waste stream is clean as far as that is concerned.
>=3D20
> If we were to use barium or lead in glazes I would want to separate
> them out into an entirely different waste stream to simplify disposal
> and reduce the amount of "contaminated" materials to dispose of with
> our hazardous waste people.
>=3D20
> anyway, long story short, the firing of our ordinary glaze materials
> into hard lumps of glass seemed in the end to be a waste of time,
> energy (gas and electricity are not free!), and effort on my part.
> This is especially since the vast majority of the material we have
> left over is clay, feldspar, and iron oxide, with varying small
> amounts of other materials that don't need to be disposed of as
> hazardous waste. we collect the stuff up and make glaze with it again
> for the most part - not what you wanted to hear, dan - but it works
> for us. sometimes it comes out with interesting and even good
> results. you might want to do a cost/benefit analysis of what it
> costs to you and the environment to fire this stuff vs. dumping it
> with the trash or even out in the garden somewhere as Mel likes to do.
>=3D20
> On Apr 24, 2011, at 10:08 AM, John Hesselberth wrote:
>>=3D20
>>=3D20
>> I think the biggest issue with firing it in bisque bowls is that the
>> bowls themselves can crack leaving you with a glob of glaze on your
>> shelf. I had this happen the one time I tried it.
>>=3D20
>> Regards,
>>=3D20
>> John
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