James Freeman on fri 18 feb 11
In days past, I reported on my experiments with mixing oxides into mineral
oil instead of water in order to keep them in suspension for long enough to
spray them through an airbrush without clogging the pickup tube. These
experiments, which involved applying the oxide over the glaze were
successful, with no adverse effects being caused by the oil.
Yesterday, I brushed the oil-based oxide onto a bisqued pot. It brushed
beautifully with the oil base, and while the bisque did still "suck in" the
oxide, it did so to a lesser extent than when using water as the base. The
brush cleaned up readily with just a bit of soap and water.
Spraying the glaze over the oxide proved enlightening. The oil caused
absolutely no problem with regard to glaze application, though common
ceramic knowledge suggested otherwise. There was no beading up of the
water-based glaze over the oil, and no cracking or pulling of the glaze
coat. The sprayed glaze layer was indistinguishable from that applied over
ordinary water-based oxide.
I unloaded the kiln a few minutes ago, and the test piece was perfect.
There was no crawling over the oil, no problems at all. Again, results
indistinguishable from conventional water-based oxide mixtures.
If it matters, the firing was to cone 6 in an electric kiln. My ramp is a
brief hold at 200 F to pull out any glaze water from the bisque, then full
rock-and-roll to very near top temperature, slowing to 200 degrees per hour
for the last 150 degrees or so, uncontrolled drop to 1900 F, 150 per hour t=
o
1700 F (only with matte or satin glazes, which this firing was), then an
uncontrolled drop, accelerated by the downdraft vent fan, to unloading
temperature.
So far I have learned that mineral oil, rather than water, is a great mediu=
m
for keeping heavy oxide particles in suspension, that it seems to cause no
problems with the glaze, whether applied over or under, and most interestin=
g
of all, that the common idea that oil on bisque can cause crawling may well
be a myth. A further benefit of an oil base over water is that the oxide
mix does not dry out, obviating any need to rehydrate and remix one's
washes.
I have yet to undertake my experiments with thinners for the mineral oil in
order to alter the brushing properties, but shall report those results once
the tests are complete.
Of course, test things out for yourself before embarking on this course, bu=
t
I am certain that the results I obtained will prove universal.
All the best.
...James
James Freeman
"...outsider artists, caught in the bog of their own consciousness, too
preciously idiosyncratic to be taken seriously."
"All I say is by way of discourse, and nothing by way of advice. I should
not speak so boldly if it were my due to be believed."
-Michel de Montaigne
http://www.jamesfreemanstudio.com
http://www.flickr.com/photos/jamesfreemanstudio/
http://www.jamesfreemanstudio.com/resources
Lee on fri 18 feb 11
On Fri, Feb 18, 2011 at 1:05 PM, James Freeman
wrote:
> In days past, I reported on my experiments with mixing oxides into minera=
=3D
l
> oil instead of water in order to keep them in suspension for long enough =
=3D
to
> spray them through an airbrush without clogging the pickup tube. =3DA0The=
se
> experiments, which involved applying the oxide over the glaze were
> successful, with no adverse effects being caused by the oil.
I wonder what advantage oil would have over the standard use of glyceri=
=3D
n?
--
=3DA0Lee Love in Minneapolis
http://mingeisota.blogspot.com/
=3DA0"Ta tIr na n-=3DF3g ar chul an tI=3D97tIr dlainn trina ch=3DE9ile"=3D9=
7that is, =3D
"The
land of eternal youth is behind the house, a beautiful land fluent
within itself." -- John O'Donohue
James Freeman on fri 18 feb 11
On Fri, Feb 18, 2011 at 7:44 PM, Adron Lilly wrote:
James,
I've been following your experiment with oil and oxides with great
interest.
Before I start experimenting I would like your thoughts on mixing a
glaze with oil/thinner and using a Critter or HVLP (gravity cup fed)
to spray it on a pot. The goal is being able to reduce indoor over
spray enough so wearing a respirator would be enough protection for
the operator.
Just guessing on my part but I think the oil might render the airborne
over spray more of a nuisance than a hazard.
Andron...
I use a Critter gun for all of my glaze spraying. Though I have never trie=
d
it, I think it would spray a mineral oil based glaze just fine. I've never
worked with an HVLP gun, so have no idea how one would work with such a
heavy-bodied medium.
I do agree with your speculation that the oil base would tame the
overspray. The overspray from a water-based glaze releases a lot of dry or
almost dry dust, which is why it goes pretty much everywhere. Based on my
airbrush experiment, I think the oil-based overspray would stay as a heavy
"goop", even when finely divided in the spray, so would not pose the same
inhalation hazard, but this is purely speculation. It would, however,
likely cause a big cleanup problem, as it would remain as a greasy slick on
any nonabsorbent surface it landed on.
I surmise that your question arises because you lack a spray booth. Before
I bought my commercial spray booth (Laguna), I used a home-made setup that
cost me $1. I posted a description of it some time ago, so it is somewhere
in the archives. It consisted of a large cardboard box measuring maybe 18"
by 18" by 24" tall, with the front cut open. I cut a rectangular hole in
the back the size of a disposable furnace filter, and taped the filter over
the hole (inside the box). I taped a smaller box to the back of the large
box, covering the furnace filter hole. This box, which was maybe 3 or 4"
deep, acted as a sort of reverse plenum and a velocity reduction chamber. =
I
cut a small hole in the back of this plenum box which accepted the hose fro=
m
a large shop vac.
In use, the shop vac drew enough air to pull most of the overspray into the
furnace filter. Most of the glaze residue that made it through the filter
fell out of the airstream inside the reverse plenum box, settling to the
bottom. A much smaller amount of glaze residue made it to the shop vac
filter, and I did not notice anything making it's way out the shop vac
exhaust (I use a Goretex filter in my shop vac). A goodly amount of the
wetter portion of the overspray simply stuck to the inside of the cardboard
spray chamber, and I would allow this to dry, and remove it when it built u=
p
thickly.
The cardboard spray chamber did get a bit soggy and saggy during extended
use, but it stiffened right back up when it dried. I got over two years us=
e
out of the thing before I got my real spray booth, and probably could have
gotten another year or two out of it. This contraption did not work as wel=
l
as my commercial spray booth, but I certainly got my dollar's worth out of
it, and it allowed me to spray a great many pots in my basement without
getting dust all over the house.
If you do decide to experiment, please let us know your results.
All the best.
...James
James Freeman
"...outsider artists, caught in the bog of their own consciousness, too
preciously idiosyncratic to be taken seriously."
"All I say is by way of discourse, and nothing by way of advice. I should
not speak so boldly if it were my due to be believed."
-Michel de Montaigne
http://www.jamesfreemanstudio.com
http://www.flickr.com/photos/jamesfreemanstudio/
http://www.jamesfreemanstudio.com/resources
marci Boskie's Mama =3D^..^=3D on sat 19 feb 11
> Lee asked:
>
> I wonder what advantage oil would have over the standard use of glyce=
rin?
We use both as china painting mediums to mix the dry paint... and
probably the main disadvantage of glycerin is that it is
hygroscopic, so if youre in a very humid area, it will pull moisture
out of the air which could result in runs and drips while the piece
is sitting,waiting to be fired.
marci the chinapainter
Lee on sat 19 feb 11
On Sat, Feb 19, 2011 at 10:58 AM, marci Boskie's Mama =3D3D^..^=3D3D
wrote:
>
> We use both as china painting mediums to mix the dry paint... and
> probably the main disadvantage of glycerin =3DA0is that it is
> hygroscopic,
I have used glycerin on bisque, and also for on glaze in Majolica.
I am guessing the resist effect of oil may be variable, depending on
the glazes.
I've thought about this because I've wondered about glaze
trailing, were the trailing would resist the glaze you put over it.
--
=3DA0Lee Love in Minneapolis
http://mingeisota.blogspot.com/
=3DA0"Ta tIr na n-=3DF3g ar chul an tI=3D97tIr dlainn trina ch=3DE9ile"=3D9=
7that is, =3D
"The
land of eternal youth is behind the house, a beautiful land fluent
within itself." -- John O'Donohue
Philip Poburka on sat 19 feb 11
HI James, all...
Far as further or other materials for experiment...
What about a Tempera kind of suspension?
Once dry, Glazed pieces would also be able to be handled much easier of
course...
James Freeman on sun 20 feb 11
Andron...
I have been doing more reading on mineral oil. Aspirated mists can cause
respiratory tract irritation, or worse if breathed in sufficient quantity.
Given this, I wouldn't spray large quantities (as in glazing an entire pot)
without a very good spray booth, even with a good respirator mask. Though
the respirator would likely protect you, it's just not worth the risk. You
trade the hazard of airborne dust for the hazard of airborne mineral oil.
Probably best to pursue another avenue for your particular application (lik=
e
stick with water for bulk glazing, and buy or build a spray booth!).
All the best.
...James
James Freeman
"...outsider artists, caught in the bog of their own consciousness, too
preciously idiosyncratic to be taken seriously."
"All I say is by way of discourse, and nothing by way of advice. I should
not speak so boldly if it were my due to be believed."
-Michel de Montaigne
http://www.jamesfreemanstudio.com
http://www.flickr.com/photos/jamesfreemanstudio/
http://www.jamesfreemanstudio.com/resources
On Fri, Feb 18, 2011 at 7:44 PM, Adron Lilly wrote:
> James,
>
> I've been following your experiment with oil and oxides with great
> interest.
>
> Before I start experimenting I would like your thoughts on mixing a
> glaze with oil/thinner and using a Critter or HVLP (gravity cup fed)
> to spray it on a pot. The goal is being able to reduce indoor over
> spray enough so wearing a respirator would be enough protection for
> the operator.
>
> Just guessing on my part but I think the oil might render the airborne
> over spray more of a nuisance than a hazard.
>
>
>
>
Adron Lilly on sun 20 feb 11
On Sun, 20 Feb 2011 09:31:16 -0500, you wrote:
James Freeman
"...I have been doing more reading on mineral oil. Aspirated mists
can cause respiratory tract irritation, or worse if breathed in
sufficient quantity."
Thanks for the information on spraying oil mixed glazes and also on
what you are doing with oil and oxides.
I'm strictly a hobby potter, just doing this for the enjoyment and
education. I'll continue to wait for warm days and spray outdoors with
a mask.
Adron
>Clayart@lsv.ceramics.org
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