Feldspar FFF?

[GreyBird]

Does anyone know what Feldspar FFF is? And do you think it's possible someone got a red like this at cone 6 in an Oxidation environment? (See Pic) ... No it's not copyrighted, It's from Glazy.org

 

[Min]

FFF is a potash feldspar. I redid the recipe using custer and adjusted it to balance with the original and used EPK for the unspecified kaolin. COE is a tiny bit lower in this version due to minor (and insignificant) differences in sodium and potassium levels. 

Glazy version of Van Gilder Tenmoku ^6 with custer

Custer Feldspar 48.20

Tricalcium Phosphate 15.50 

Talc 17.40

Silica 8.60

Lithium Carbonate 4.20

EP Kaolin 6.20

total: 100.00

Iron Oxide Red 11.7

Bentonite 2

Version of the Van Gilder iron red that I have, from my notes:

Van Gilder Iron Red ^6

F4 feldspar 46.7 (can sub Minspar)

Tricalcium Phosphate 15

Silica 11.4

Lithium Carb 4

EPK 4

Talc 16.9

Bentonite 2

total 100

Crocus martis 8.5

Iron Oxide Red 3

[GreyBird]

Do you think this is pictured on Porcelain and that's why it's so bright red? Wouldn't it be wonderful if Glazy.org had a field to enter clay body pictured or if people would just add that very important bit in descriptions. I would love to search via glazes pictured on Medium stoneware.

Min, Can you tell me why you added theVan guilder's Iron Red Recipe?

 

[Min]

12 hours ago, GreyBird said:

Min, Can you tell me why you added theVan guilder's Iron Red Recipe?

Have a look at the ingredients. Major difference is the type of feldspar, potash in the original recipe you posted and a soda feldspar in the second. Also look at the type of iron used.

There are many moving parts to an iron red. Thickness of the glaze is huge too. The large amount of iron used causes the glaze to jell so the inclination is to add more water to bring it to a typical glaze thickness. Problem is the glaze layer is likely going to be too thin. I would suggest measuring the specific gravity to 1.42, adding just enough water to get it there, then adding a tiny amount of darvan to get it to a good dipping "thickness".

If I was attacking this glaze I would do 2 line blends, one with a soda spar base glaze plus another with a potash base glaze, like the 2 recipes I posted above, and do a progression blend of 10 iron up to 20 iron in both of them on a light and a dark claybody. I would make 2 tall test tiles for each glaze, dip the tiles in 1 dip over the top 2/3 of the tiles and double dip the very top of the tiles. ( iron reds can run if too thick so allow room for this) Fire one set of tiles with a slow cooling ramp down and the other with a fast cool. I would do this for which ever clay I was using. I would also be looking at the iron used.

[GreyBird]

Thanks... will do

[Magnolia Mud Research]

FFF feldspar is a brand of feldspar sourced from Finland.  

LT

[High Bridge Pottery]

It's hard to tell but looking at Joe Thompson's other entries most seem to be a porcelain or white stoneware. Porcelain will certainly give you brighter colours.

 

The tricalcium phosphate if I remember is giving you that colour of iron, would still be similar on stoneware I think.

[GreyBird]

6 minutes ago, High Bridge Pottery said:

It's hard to tell but looking at Joe Thompson's other entries most seem to be a porcelain or white stoneware. Porcelain will certainly give you brighter colours.

 

The tricalcium phosphate if I remember is giving you that colour of iron, would still be similar on stoneware I think.

Would Bone Ash be the same as Tricalcium Phosphate?

[Mark C.]

(Would Bone Ash be the same as Tricalcium Phosphate?)

 

no these are not the exactly the same as i use both in glazes depending on the glaze formula 

The Tricalcium seems to make my iron red Brighter(reder) than regular bone ash

I'm firing porcelain to cone 11.

Here's my iron red glaze from my todays lunch  mug-its a rockfish mug-about 14 oz

[GreyBird]

Thanks You and VERY cool mug. I assume this mug uses Tricalcium? PS Where do you get it. My search in my usual Ceramic shops just brings up bone ash. 

[Mark C.]

Yes it does.

I was given a 50# bag thats almost used up just making this glaze.As thats all I use it in.

I always have used a saturated Iron glaze in my work-over 45 years that glaze has changed many times-this is the current one I'm using.

Its was a published glaze in Ceramics Monthly(CM) a few years back

[GreyBird]

This is all I cold find: https://www.myspicer.com/shop/tricalcium-phosphate/

Ah Found it here. But they are just calling it Synthetic Bone Ash: https://www.axner.com/tri-calcium-phosphate.aspx

[Mark C.]

Another pot with this glaze that came out yesterday is here

Your axner link is the right stuff

[Mark C.]

It also makes for better crystals -Its been the best Iron red I have yet to use.

[Mark C.]

Its also sold here much closer to you-I think cheaper as well-they can fit it in a usps flat rate box-often the best shipping deal with materials.

This stuff is super light and bulky though.

https://uspigment.com/product/bone-ash-tcp/

[GreyBird]

OOpps, next time. I already ordered from Axner

[Mark C.]

US pigments is always worth a look for materials/colorants/stains etc

[GreyBird]

I book marked it

[C.Banks]

John Sankey  has some detailed iron red information you might be able to use: Iron Glazes

 

[neilestrick]

On 9/9/2018 at 2:32 PM, High Bridge Pottery said:

Porcelain will certainly give you brighter colours.

Not necessarily. Many iron reds are brighter on dark stoneware bodies. The one I mix for my studio is best on dark stoneware, worst on porcelain.