Penland Red-Orange posted by Michele Hartung 6/29/2011

[George Lewter]

Penland Red-Orange posted by Michele Hartung 6/29/2011   

Feldspar, F-4       46.70 

Talc         16.90 

Bone Ash     15.00 

Crocus Martis      11.50 

Silica         11.40 

Kaolin, EPK           4.00 

Lithium Carb         4.00 

Bentonite             2.00
                    111.50

Comment by Michele Hartung on July 27, 2011 at 3:44pm. This is without reduction.  It is Penland Red-Orange on Highwaters Loafers Glory clay.  It is dipped in "thick" glaze (or dipped twice in a thinner version)  and given a 30 minute soak at peak, cone 6.  Ends up at cone 7.  If you are going to try this glaze, layer it on very thickly, otherwise you get brown.

[Norm Stuart]

Ceramic Supply sells Lanxess Bayferrox 130 as Crocus Martis.

I'd like to find out what product Mid-South sold as crocus martis, which Michele Hartung used to make the bright red in the photo.

Just click on "MSDS Sheets for Raw Matierals" on this page: http://ceramicsupplyinc.com/help-and-links.aspx

The MSDS Ceramic Supply provides for their Crocus Martis is from Standard Ceramics.com - so they are either the same company or they buy from Standard Ceramics.

The MSDS says the Crocus Martis they're selling is actually Lanxess Bayferrox, but they don't specify which product it is. But I know from previously contacting Standard Ceramic that the crocus martis they sell is actually "Bayferrox 130". This is only 94.3% Fe2O3 with 1% LOI and 4.7% unspecified.

http://bayferrox.com/fileadmin/pdf/IPG/00006211_000_BF-130-M-ENG.pdf

Jette Nielsen said:

You can get it from:
http://ceramicsupplyinc.com/chemicals.aspx
Norm Stuart said:

Michele - Mid-South Ceramics doesn't currently list "Crocus Martis".  It would be wonderful if they gave you an MSDS for what they sold you.

The MSDS (Material Safety Disclosure Sheet) will essentially tell us what commercial red pigment Mid-South sold you as "Crocus Martis". I'm convinced using the correct product is the key to producing the right red color.

Michele Hartung said:

Mid-South ceramics in Nashville, Tennessee, although you can probably find it at a dealer near you!

[Norm Stuart]

Ceramic Supply sells Lanxess Bayferrox 130 as Crocus Martis.

I'd like to find out what product Mid-South sold as crocus martis, which Michele Hartung used to make the bright red in the photo.

Just click on "MSDS Sheets for Raw Matierals" on this page: http://ceramicsupplyinc.com/help-and-links.aspx

The MSDS Ceramic Supply provides for their Crocus Martis is from Standard Ceramics.com - so they are either the same company or they buy from Standard Ceramics.

The MSDS says the Crocus Martis they're selling is actually Lanxess Bayferrox, but they don't specify which product it is. But I know from previously contacting Standard Ceramic that the crocus martis they sell is actually "Bayferrox 130". This is only 94.3% Fe2O3 with 1% LOI and 4.7% unspecified.

http://bayferrox.com/fileadmin/pdf/IPG/00006211_000_BF-130-M-ENG.pdf

The bottom line is there is no such thing as Crocus Martis.  We need to find out from each supplier what specific Bayferrox product they sell as crocus martis, because the specific product each seller chooses is different. Others use Bayferrox 180 as crocus martis. This product is blueish red and is 97.3% Fe2O3, with 0.6% LOI and 2% unspecified.

http://bayferrox.com/fileadmin/pdf/IPG/00006289_000_BF-180-ENG.pdf

Jette Nielsen said:

You can get it from:
http://ceramicsupplyinc.com/chemicals.aspx

Jette Nielsen said:

You can get crocus martis from:
http://ceramicsupplyinc.com/chemicals.aspx

[Norm Stuart]

This beautiful version of Penland Red-Orange glaze was made by Michele Hartung with 97.3% pure Bayferrox-180.

Mid-South Ceramics Supply <[e-mail]>

Our Crocus Martis is the Bayferrox 180.
---
Mid-South Ceramics
615-242-0300
866-203-5286
www.midsouthceramics.com

http://bayferrox.com/fileadmin/pdf/IPG/00006289_000_BF-180-ENG.pdf

97.3% Red Iron Oxide and 0.6% LOI.  The remaining 2.1% is mostly silica.

[Sofia Donovan]

What ingredient is Crocus Martis? I live in Chile and need a substitute for it.

[Norm Stuart]

Crocus Martis has two explanations.

The first explanation was it was a natural hydrated iron ore, purple-blue in color, from an African mine, which hasn't been available for at least 35 years. I tend to believe this explanation and have substituted yellow iron oxide, a man-made hydrated iron, for crocus martis. When I have substituted the Prominfer "Spanish Iron Oxide ore", the glaze colors come out too dark from too much iron.

Ceramic artists asking for crocus martis have led some vendors to find something / anything they can sell ad Crocus Martis to make their buyers happy.

A few years ago New Mexico Clay took to selling Bayer Chemical Bayferrox 185 which due to its small crystalline size has a purple color, but the results are the same as using any man-made red iron oxide.

Another vendor, "The Ceramic Shop" has now claimed crocus martis is a mythical brand name for anhydrous iron sulfate, which readily dissolves in water turning green. But the only people who've ever used that brand name is The Ceramic Shop. As bogus as anything can be http://www.theceramicshop.com/product/361/Crocus-Martis/

I find it hard to believe that for 50 years potters used a water soluble ingredient - it makes no sense. But for lack of a better explanation, Tony Hansen at Digitalfire provides at this link the chemistry for iron sulfate as it is cheap and naive potters now buy it. -  Digitalfire Crocus Matrtis

Man-made high purity Red Iron Oxide does start with creating soluble iron sulphate, which is perhaps what gave the vendor the idea. Partially evaporating the water grows pure iron sulfate crystals which naturally and cheaply delivers a pure product. This pure iron sulfate is then fired in an industrial kiln with oxygen, creating 99%+ pure red iron oxide crystals and noxious sulfur dioxide which is recycled into creating more iron sulfate.

This process was patented by Bayer to make pure red iron oxide of various particle sizes to use as red ink pigment and red coloring for cement. Most Bayer process "man-made" iron oxide is now made in China. I have found the larger particle size creates a redder glaze. Why? At Cone 6 and below, red iron oxide usually resists decomposition into black iron oxide. So with larger particles more of the red iron oxide survives and creates a crystallization matrix for iron oxide during cooling which did degrade. So the bright red you add to the glaze comes out bright red after the firing especially in a glaze containing phosphorous.