Michael Banks on thu 17 feb 00
David Hewitt wrote:
----- Original Message -----
> I have now had a chance of talking to John Beeston of Potclays.
> His answer is that their black iron oxide is mainly FeO - 75% to 80% and
> the rest Fe3O4 magnetite. They obtain it from a German supplier and
> described it as a pre-processed material rather than synthetic.
> Red iron oxide for pottery suppliers, he said, was all synthetically
> produced these days in this country.
Thanks very much David,
Seems that Frank Hamer is 75 to 80% right! At least in the UK. The reality
of iron oxide supplies and composition seems to be quite complicated. It
would appear that geographic factors are at work here. As the UK is a long
way from working iron ore deposits these days, I would expect that
chemically refined materials will be more common than in Australasia or
Brazil -close to mega mines. It would be interesting to hear what is sold
to potters in the NE of North America, where magnetite and hematite are
mined on a large scale from taconite ore in the Lake Superior region.
Tricky for calc calculation software programmers who wish to cater to an
international audience.
The fact that synthetic RIO (Fe2O3) is sold by Potclays is interesting. I
wonder how it is made in the UK? If it is chemically precipitated
material -the purity may be very high, which will be of interest to celadon
and kaki enthusiasts.
New Zealand is a big producer and exporter of magnetite (from beach sand),
though potters almost never use it (except for the odd person for
speckling). The red iron oxide is mostly imported and I believe this is
calcined limonite ore from Western Australia.
Michael Banks,
Nelson,
NZ
Steve Mills on fri 28 may 10
Dear Bill,
You've touched on one of the most important areas of this Craft of ours.
When I first started potting, I soon found whose materials I could rely on
to be consistent, and when my Wife & I started our Supply Business we made
it our goal to use the same sources for all our materials come what may.
Iron oxide was a case in point, there were more than 40 variations at one
source, but after much research we came down on a particular Synthetic Iron
Oxide as our base, because being a manufactured material, and used by the
Paint Industry (as you pointed out), rather than a natural one, its
performance could be completely relied on, especially as we were making and
selling our own range of Stoneware Glazes designed by our partner Mike
Bailey.
.
Potters need absolute reliability, and in 25 years we only had to change on=
e
material. Thankfully we were able to supply the fix for our customers to
adapt to the new supply, so that was relatively painless.
As a process it wasn't easy, and we were not the cheapest in some cases, bu=
t
it was a reputation we were (and are) proud of, and we will always be
grateful to those who helped us achieve our goal.
Steve M
On 28 May 2010 19:09, Bill Merrill wrote:
> This issue of iron will depend on what iron you are able to get from
> your local clay supply dealer. They will have the information about the
> iron they are selling.
>
>
>
> If you want other irons they will more than likely sold in a minimum of
> a 50 pound sack of any particular iron. If there are several potters
> who need iron go together and buy a 50 pound of good iron. Good iron
> does not mean 100% pure iron. Some irons are very strong and will not
> give you the quality you want for example in a red mat glaze.
>
>
>
> I use an iron numbered R2199D. It is a iron that is also used by paint
> companies. If you can locate this iron
>
>
>
> I use the example about iron reducing and oxidizing .....take a piece of
> new angle iron, subject it to water, especially salt water and it will
> rust and turn to a orange "rust" color. If you have red iron in a
> reduction clay body, reduction
>
> Fire the body, the body will turn orange brown. The body oxidizes as it
> cools and turns the reduced iron orange.
>
> If the body is broken open you will see the interior of the body is
> grey, a reduced iron does this because the interior cannot re-oxidize
> as it cools.
>
> One of the best iron oxides I have used was made by Pfizer. Of course,
> as time moves on and companies we knew in the past have been purchased
> by another company , sold and resold. Pfizer became Elementis which
> became Rockwood Industries. The current distributor for Rockwood is a
> company named TCR Industries. I have not had to purchase any iron since
> I had 50 pounds of red iron. R2199D is a rich red, not a dark red. It
> works extremely well for reduction red mat glazes. and every glaze I use
> that needs red iron. The number of the iron I use is R2199D iron oxide.
> Elementis has the R2199D listed on their site.
>
>
>
--
Steve
Bath
UK
www.mudslinger.me.uk
Growing old is inevitable, growing up is optional!
Bill Merrill on fri 28 may 10
This issue of iron will depend on what iron you are able to get from
your local clay supply dealer. They will have the information about the
iron they are selling.
=3D20
If you want other irons they will more than likely sold in a minimum of
a 50 pound sack of any particular iron. If there are several potters
who need iron go together and buy a 50 pound of good iron. Good iron
does not mean 100% pure iron. Some irons are very strong and will not
give you the quality you want for example in a red mat glaze.
=3D20
I use an iron numbered R2199D. It is a iron that is also used by paint
companies. If you can locate this iron
=3D20
I use the example about iron reducing and oxidizing .....take a piece of
new angle iron, subject it to water, especially salt water and it will
rust and turn to a orange "rust" color. If you have red iron in a
reduction clay body, reduction=3D20
Fire the body, the body will turn orange brown. The body oxidizes as it
cools and turns the reduced iron orange.
If the body is broken open you will see the interior of the body is
grey, a reduced iron does this because the interior cannot re-oxidize
as it cools.
One of the best iron oxides I have used was made by Pfizer. Of course,
as time moves on and companies we knew in the past have been purchased
by another company , sold and resold. Pfizer became Elementis which
became Rockwood Industries. The current distributor for Rockwood is a
company named TCR Industries. I have not had to purchase any iron since
I had 50 pounds of red iron. R2199D is a rich red, not a dark red. It
works extremely well for reduction red mat glazes. and every glaze I use
that needs red iron. The number of the iron I use is R2199D iron oxide.
Elementis has the R2199D listed on their site.=3D20
=3D20
Lee Love on sat 29 may 10
When dealing with industrial materials, purity and uniformity are easy to g=
=3D
et.
What I am always looking for are more natural materials, which
allow unexpected things to happen.
These materials are hard to find here, so sometimes you just have
to mix them up to try and get something similar, to get the effects of
iron oxide from spangle or impure cobalt like Gosu.
I often get the iron I need from iron bearing clay like
redart or ocher. And sometimes sand and gravel.
--=3D20
--
Lee, a Mashiko potter in Minneapolis
http://mingeisota.blogspot.com/
=3D93Observe the wonders as they occur around you. Don't claim them. Feel
the artistry moving through and be silent.=3D94 --Rumi
Bill Merrill on mon 3 oct 11
A good synthetic iron oxide that is most excellent is NUBIOLA R 5510.
R5510 replaces RD 2199 . I buy it in 50 pound bags, It is $ 1.50 per
pound. I buy it from CDI ,Chemical Distributors, INC In Seattle or
Portland, OR. Don Crookshank is a contact person there. His number is
503-243-1082.
CDI sells clay etc. in large amounts, so 50 pounds of iron oxide is the
least you can buy.
Bill Merrill
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