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docweathers

Red/pink/purple/mauve

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I saw this at a craftrs fair and it was fantastic. Has anyone tried this. I just get a bland mauve. What is the secret?

 


Red/Pink Purple/Mauve ^6

Gerstley borate 21 % Nepheline Syenite 16 % Kaolin 11 % Whiting 20 % Silica 32 % Tin 5 % Chrome 0.15%

 

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I'm just looking to duplicate the glazes I saw on the beautiful pots at the art show.  I'm going to another art show this weekend and I suspect the same lady will be there, so possibly I can pry more information out of her about how to make the thing work.  apparently at the glaze that she found in clay times many years ago.

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The formula I have is the same. I found it in an old issue of Ceramics Monthly. I tried it twice and got a purple/mauve color. There was a note with the recipe that said that if it is too thick it will turn mauve. It also said it is best done in an electric kiln.  I fired in an electric kiln and thought I put it on pretty thin but I didn't get a red. The clay body probably is more important with thin glazes. I don't plan on doing any more with this glaze. Too many other things to get done.

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I've/we've never had any luck with reds. Most turn out a muddy brown or putrid purple. If you find one that works in ^6 oxidation PLEASE share!

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A nice cone 6 oxidation red that I like is Reader's Digest Red

 

Gerstley Borate   31

Flint                     30

Kona-4 Feldspar 20

Talc                     14

EPK Kaolin           5

 

Total                 100

 

Also add: Red Iron Oxide15

 

 

Pretty Good for Texture. It goes from Brick Red to Red/Orange when thick, breaks black.  Satin/Shiny.  Moves – keep clearance from bottom. You can increase the texturing by spraying a little ash over it.

 

 

----

here's another one that I'm experimenting with

 

Cone: 6 Color: Candy Apple Red

Firing: Oxidation Surface: Glossy

 

Amount Ingredient

21 Gerstley Borate

16 Nepheline Syenite

11 Kaolin--EPK

32 Silica

20 Whiting

 

100 Total

 

Additives

.2 Chromium Oxide (that is point 2)

5 Tin Oxide

Comments: This glaze needs three thick coats, thick. It will break white if thin and on edges. When it is applied right it will produce a very nice candy apple red that has a very waxy feel.

 

I think the key phrase here is "thick", very thick, thicker than thick

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Thanks Larry! While neither are the red I'm looking for, both are beautiful. The Readers Digest is one I want to try. I like the floating look as well as how it breaks! Did you use ash in the first photo?

 

Thanks!

Pam

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here is the best I could do with chrome red. It was the same as posted by docweathers. This was fired to cone 5 on Laguna MR5 stoneware. It was put on 2x as thick on the left edge of the tile. Made no difference in color. It's pretty but it ain't "red" I also had some trouble with pinholes on a larger piece.

 

 

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The problem is that chrome and tin make a color that is closer to magenta, and red is actually made up of a combination of magenta and yellow, so you have to find a way to introduce yellow into the recipe.


 


I tried mixing Mason stain praseodymium yellow and 6006, it only sort of worked, maybe raw materials would mix better, maybe use a clay for the recipe that is very yellow? So many things to experiment on and so little time.


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The problem is that chrome and tin make a color that is closer to magenta, and red is actually made up of a combination of magenta and yellow, so you have to find a way to introduce yellow into the recipe.

 

I tried mixing Mason stain praseodymium yellow and 6006, it only sort of worked, maybe raw materials would mix better, maybe use a clay for the recipe that is very yellow? So many things to experiment on and so little time.

 

 

Interesting. Maybe Vanadium or Zirconium. Tempted to add it to the couple of hundred test I'd like to find time to run.

 

Jim

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Technically, it's referred to as a chrome-tin pink. The idea is that we get the pink saturated enough that it looks more red. It will never be as pure and deep a red as a copper red (reduction fired cone 10 glaze), but you can get it close. It will always be slightly more purple. C-t pinks will get better color on a white clay, especially porcelain, and develop better color when applied thickly. A controlled cooling also helps. I cool at 175F per hour down to 1500F.

 

The biggest problem with c-t pinks is that they use a lot of tin, anywhere from 5-7% (more than a pound in a 10,000 gram 5 gallon bucket), and tin costs a fortune right now!

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You have just cleared up a problem that I have been fumbling with for some time. I fire a cone 6.  A lot of my reds ended being brown. And you guessed it, I'm using Laguna red iron oxide. I'm going to switch to US pigment Synthetic RIO . Can the Laguna red iron oxide be used as rat poison or fertilizer or? :(

 

 

Thanks

 

Larry

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Which "red iron oxide" you use as a raw ingredient makes a huge difference in whether a red iron glaze comes our red or brown. 

 

If you stay below cone 7, the red iron oxide you start off with is pretty much the red iron oxide you'll end up with.  Fire the glaze hotter and longer, and you'll end up with black iron oxide which has to be converted back to red iron oxide during the cooling phase of the firing.

 

Using a synthetic red iron oxide with a large particle size will result in a large amount to red iron oxide crystals for free iron to form onto. Using a small particle size red iron oxide at higher temperatures may result in a complete degradation of the red iron.

 

 

Synthetic Red Iron Oxide is made with Iron Sulfate crystals, which is nearly 100% pure due to the crystallization process - crystallization is a cheap way to purify something. These green crystals are then fired with oxygen creating a Red Iron oxide of 98% purity or better.

 

This is a photo of US Pigment High Purity (synthetic) Red Iron Oxide and Laguna Clay Red Iron Oxide. Although they look almost identical, the Laguna product fires brown while the US Pigment product fires red.

med_gallery_18533_643_48368.jpg

 

 

Here's Richard Busch Nutmeg made with three different types of Red Iron Oxide:

 

Laguna Red Iron Oxide

med_gallery_18533_643_436632.jpg

 

US Pigment High Purity Red Iron Oxide

med_gallery_18533_643_52190.jpg

 

Prominsa Spanish Iron Oxide (sold by Laguna and many other vendors)

med_gallery_18533_643_266512.jpg

 

 

The difference between Promindsa Spanish Iron Oxide and Laguna Red Iron Oxide is less subtle.

med_gallery_18533_643_1660904.jpg

 

 

Attached are some pictures of these glazes

 

 

  attachicon.gifReaders Digest Red.jpgattachicon.gifReadersDigestRed.JPGattachicon.gifCandy Apple Red.jpg

 

Doc, are you using 15% RIO in the Readers Digest? Mine comes out a lot darker. Your gold color looks better.

 

Jim

 

 

Where does US pigments natural iron oxide fit into this?

I agree with that I agree that one needs to be picky about one's glaze Ingredients, but how do you know  where the best ones are? You think a company like Laguna would not be supplying second-rate materials, but obviously they are. I know you can run tests on everything, but that would be an overwhelming task. At some point you've got to figure out who you can trust and who you can't. Can we make a list of quality suppliers? If I understand right, we can put US Pigment at the beginning of that list. Who else can we add?

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Where does US pigments natural iron oxide fit into this?

I agree with that I agree that one needs to be picky about one's glaze Ingredients, but how do you know  where the best ones are? You think a company like Laguna would not be supplying second-rate materials, but obviously they are. I know you can run tests on everything, but that would be an overwhelming task. At some point you've got to figure out who you can trust and who you can't. Can we make a list of quality suppliers? If I understand right, we can put US Pigment at the beginning of that list. Who else can we add?

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You revelations have certainly save me a huge amount of time figuring out why my glazes were turning out so brown and drab.

 

Are there any other glaze materials that you done similar research on and found problems?

 

I used to buy all of my stuff from Laguna. A few months ago Jon Brooks and I cross swords.  Since then I buy nothing from Laguna . This revelation puts the final nail in their coffin. I think you have him pegged right.  He also has no prospective on how potter social networks operate and what a bad reputation my cost him.

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I've not been able to get an MSDS sheet for the synthetic red iron oxide from Sayed at US Pigment, which doesn't please me, but his "Red Iron Oxide (High Purity)" does fire the reddest. He says it comes from China which has some Bayferrox licensees as well as companies using the Bayer process without license.  As for his regular grade red iron oxide, just like his "High Purity", see if you can get Sayed to send you an MSDS.  When I spoke to him it was like he had no idea what I was talking about, which isn't possible being in his business.

 

The next best is Standard Ceramic's Iron Oxide, Red, Precipitate which is Bayferrox 140.  A lot of East Coast US vendors buy from Standard Ceramic.  http://www.standardceramic.com/MSDSmaterials/Iron%20Oxide%20-%20Red%20Precip.pdf

 

As you can see Laguna Clay has a number of MSDS sheets for Red Iron Oxide, ranging from the absolute worst from Rockwood Pigments to Promindsa products, the company which makes the "Spanish Iron Oxide" every vendor in the US sells.   I've asked Juan, the Tech Support lead at Laguna, if they can't carry Bayferrox or some other synthetic red iron oxide, but the answer is no.  If I or someone else could talk with Julie Brooks personally I'm sure the answer could be different.  I just don't think Jon realizes there's such a huge difference in these products - he just strikes me as a self-perceived shrewd negotiator looking for the good deal.

http://www.lagunacla...y/mirox4284.pdf

http://www.lagunacla.../miroxspain.pdf

http://www.lagunacla...ry/miroxr03.pdf

 

What I found particularly annoying is how long it took for me to figure out our problem with red iron glazes and to trace it  back to bags from Laguna.  That's when I began reading MSDS sheets.  Even worse Laguna charges more per pound for an unknown red iron oxide that fires ugly than US Pigment charges for their unknown which fires red. With US Pigment we have to pay for shipping which wouldn't be the case if I could just get Laguna to carry a synthetic red iron oxide.

 

New Mexico Clay and several other vendors sell Bayferrox 132 as Crocus Martis - a product that hasn't existed for many decades.  But 132 is a smaller granule product which can result in heat degradation.  Jeff Poulter tried some and found it fired less red than the Standard Ceramic synthetic.  This could also be what US Pigment sells as "Red Iron Oxide (Pink)".

 

This is a test tile of "Floating Red (Oxblood Red)" with synthetic red iron oxide from Digitalfire (aka Amaco Ancient Japser) over a layer of Amaco "Firebrick Red".  You can clearly see that Firebrick Red is a pigment like a Red Mason Stain rather than an iron oxide glaze.  http://www.digitalfire.com/gerstleyborate/recipes/floatingblue.html

54.88%  Gertley Borate

14.63%  Talc

30.49%  Silica

21.95%  Red Iron Oxide

med_gallery_18533_643_1163547.jpg

 

 

Where does US pigments natural iron oxide fit into this?

I agree with that I agree that one needs to be picky about one's glaze Ingredients, but how do you know  where the best ones are? You think a company like Laguna would not be supplying second-rate materials, but obviously they are. I know you can run tests on everything, but that would be an overwhelming task. At some point you've got to figure out who you can trust and who you can't. Can we make a list of quality suppliers? If I understand right, we can put US Pigment at the beginning of that list. Who else can we add?

 

Here is a google drive link to a folder with all the MSDS sheet for all of US pigments iron oxides  https://drive.google.com/folderview?id=0B74t5cHBHat2SWdQUzkyb1JRNzg&usp=sharing.

 

Since I don't know what I'm looking at with these things, I would appreciate your reaction to the high purity iron oxide.

 

Larry

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Oops, I told you I didn't know what I was looking at.

 

In the Fe304.pdf  it has "Synthetic Iron Oxide" .... I thought that was a key term therefore the relevant PDF. I wrote Syed again and asked if I could also have the high purity MSDS. I probably won't get it but it's worth another try.

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