Bone Ash-todays topic

[Mark C.]

Ok in another thread bone ash was brought up -that was all about Oribe glaze

Todays update after mixing glazes this am for me is all about bone ash

So on that  synthetic bone ash I just finished a full 50# bag of it  today (this bag was a gif to me )as I use it only in my red/black (high Iron) saturate glaze also  I use synthetic red iron only in this glaze. I have another 50# bag ready to go. The cost of this has really gone up lately. I used up 50#s in less than a  decade  in only one glaze -my Red-Black cone 10 glaze

I still use my natural bone ash in any other glazes like Oribe -I use very little in this application

Now its still  avaliable in both forms  at least thru Laguna Clay Co /Axner

and  my guess most other outlets

natural bone ash for me is  about 1$ per# for 50#s much cheaper than  synthetic made from cow bones

 synthetic tri-Calcium Phosphate is 3.09 a # in a 50# bag for me

Mind you my prices are lower than yours but the relationship is the same so you can see what you are using

So your cost will tell you what type you have.

 

In terms of use this double use of synthetics give my glaze a super rich color not found in most iron saturated glazes. Its more costly to make but worth it. It about the 4th or 5 iron saturate glaze I have used in my line of forms over the past 45 years . Since its so bright it jumps out. I no longer use lesser Iron saturates.

I got this glaze in a issue CM about 6-10 years ago-I do not recall exactly

This is cone 10 reduction fired but will pop at cone 10 oxidation as well

I use it on Porcelain 

I can post it if there is interest 

 

 

[neilestrick]

I haven't used real bone ash in decades, so I can't remember if it's true or not, but I was told that real bone ash tends to stink in the glaze bucket, synthetic does not.

I have Harris Red (cone 6) in my studio- you can find the recipe all over the internet. My students love it , and it's the most consistent glaze ever. Well worth the cost of bone ash. We have the best results on brown clays, like Standard 112.

[liambesaw]

My suppliers have real bone ash at 3 dollars a pound in a 50lb bag, and 2 dollars a pound for TCP.

[CactusPots]

13 hours ago, Mark C. said:

Ok in another thread bone ash was brought up -that was all about Oribe glaze

Todays update after mixing glazes this am for me is all about bone ash

So on that  synthetic bone ash I just finished a full 50# bag of it  today (this bag was a gif to me )as I use it only in my red/black (high Iron) saturate glaze also  I use synthetic red iron only in this glaze. I have another 50# bag ready to go. The cost of this has really gone up lately. I used up 50#s in less than a  decade  in only one glaze -my Red-Black cone 10 glaze

I still use my natural bone ash in any other glazes like Oribe -I use very little in this application

Now its still  avaliable in both forms  at least thru Laguna Clay Co /Axner

and  my guess most other outlets

natural bone ash for me is  about 1$ per# for 50#s much cheaper than  synthetic made from cow bones

 synthetic tri-Calcium Phosphate is 3.09 a # in a 50# bag for me

Mind you my prices are lower than yours but the relationship is the same so you can see what you are using

So your cost will tell you what type you have.

 

In terms of use this double use of synthetics give my glaze a super rich color not found in most iron saturated glazes. Its more costly to make but worth it. It about the 4th or 5 iron saturate glaze I have used in my line of forms over the past 45 years . Since its so bright it jumps out. I no longer use lesser Iron saturates.

I got this glaze in a issue CM about 6-10 years ago-I do not recall exactly

This is cone 10 reduction fired but will pop at cone 10 oxidation as well

I use it on Porcelain 

I can post it if there is interest 

 

 

I'd like to see the glaze.  Would this be considered a good food safe glaze? 

Not many of us firing cone 10 anymore I think.

[Mark C.]

(Not many of us firing cone 10 anymore I think.)

On this forum its 99% cone 6 but thats not refective of what I see in my area of the world (western state shows)

I will add out local JC just switched to a all cone 6 program as they had to move the pottery shop to a new building (standar class room) and lost their Tech funding and it was easier for one instructor to fire electric with store bought  glazes than mix all the glazes and fire a gas kiln-this switch was done for ease of use for 1 instructor . It was a bit of a shame as the local high school has a cone 10 program and that JC had a 40 year cone 10 program so kids where all working in cone 10 thru high school and junior collage now they switch to cone 6 . Our State collage still is cone 10 and cone 06

I only know potters firing to cone 10 out west here making a living-even our local public clay center with classes fires to cone 10

I see only a few potters in cone 6 at shows in the west-most all are still cone 10.

I'll bring the glaze formula in today from studio and post it -its glaze day for me glaze and load two kilns

[CactusPots]

4 hours ago, Mark C. said:

(Not many of us firing cone 10 anymore I think.)

On this forum its 99% cone 6 but thats not refective of what I see in my area of the world (western state shows)

I will add out local JC just switched to a all cone 6 program as they had to move the pottery shop to a new building (standar class room) and lost their Tech funding and it was easier for one instructor to fire electric with store bought  glazes than mix all the glazes and fire a gas kiln-this switch was done for ease of use for 1 instructor . It was a bit of a shame as the local high school has a cone 10 program and that JC had a 40 year cone 10 program so kids where all working in cone 10 thru high school and junior collage now they switch to cone 6 . Our State collage still is cone 10 and cone 06

I only know potters firing to cone 10 out west here making a living-even our local public clay center with classes fires to cone 10

I see only a few potters in cone 6 at shows in the west-most all are still cone 10.

I'll bring the glaze formula in today from studio and post it -its glaze day for me glaze and load two kilns

Not surprising to me your explanation is mostly centered around academic ceramics.  That's where most ceramics happens. 

Also, Cone 6 electric is just easier in every way than cone 10 reduction.  Some of those ways are a very big deal.

[Min]

6 hours ago, CactusPots said:

Also, Cone 6 electric is just easier in every way than cone 10 reduction.  Some of those ways are a very big deal.

Interesting thought, care to elaborate on this?

[Mark C.]

There is no easy in ceramics is my view no matter what cone temps 

That said the glaze from a CM article in past decade

Iron Cristaline glaze cone 11-12

synthetic bone ask tri-Calcium Phosphate 12%

Talc----I use Sierra lite-                                               9%

Whiting                                                                               9%

custar feldspar                                                               48%

EPK                                                                                        6%

silica 325 mesh                                                              16%

synthetic red iron oxide                                             11.5% 

Total 99.5%

It likes it hot

I fire it to 10-11 myself for best results but it looks fine in cooler areasas well just less crystals

 

 

[CactusPots]

12 hours ago, Min said:

Interesting thought, care to elaborate on this?

Challenge accepted.   Both have inherent complications, gas firing simply has more.  No where is gas easier or simpler. 

Obviously, first off, the management of atmosphere.  Balancing damper and gas pressure.  Knowing the kiln well enough to work with uneven reduction.

Putting aside the modified electric to gas conversions, a typical gas kiln costs substantially more than a typical electric kiln.  I would describe the typical gas kiln as about 24 cubic ft and the typical electric as 7-10, so a typical gas kiln has a larger footprint.

An electric kiln is more likely to have an automatic programmable controller

If someone asks advise such as " I want to do some ceramics, the space I have is my garage"   Electric kiln.  Rarely does someone start with a gas kiln now.

If I think of more, I'll modify this post.

 

[Min]

@CactusPots, thanks for your reply. I wasn't actually thinking of it as a challenge, just curious if you were going to go into your thoughts on glazes as well as the firing. Perhaps we could turn this into a Question of the Week for @Pres? Are you okay with this if I suggest it?

[CactusPots]

12 hours ago, Mark C. said:

There is no easy in ceramics is my view no matter what cone temps 

That said the glaze from a CM article in past decade

Iron Cristaline glaze cone 11-12

synthetic bone ask tri-Calcium Phosphate 12%

Talc----I use Sierra lite-                                               9%

Whiting                                                                               9%

custar feldspar                                                               48%

EPK                                                                                        6%

silica 325 mesh                                                              16%

synthetic red iron oxide                                             11.5% 

Total 99.5%

It likes it hot

I fire it to 10-11 myself for best results but it looks fine in cooler areasas well just less crystals

 

 

I hate to even ask, as my materials storage is really full.  I did think I had every available raw glaze ingredient, now you ask for synthetic red iron oxide.  O Well.

It's not even on Baileys or Laguna catalog.  Where to get?  I assume it's more "powerful" than red or even black iron oxide.   Is that the difference?   Is there a substitution ratio? 

What difference would I see if I ran tests between RIO and synthetic?  For that matter Bone Ash and the synthetic?   Just More Better?

[Min]

3 minutes ago, CactusPots said:

I did think I had every available raw glaze ingredient, now you ask for synthetic red iron oxide.

Yes, there is a difference. Try looking for high purity red iron oxide, I use the stuff from US Pigments. 

Natural Red Iron Oxide is approx 85% purity, Spanish Red Iron Oxide  approx 83–88% purity, and Synthetic Red Iron Oxide aka High Purity Red Iron Oxide is 96–99% purity. I had a friend who only had the Spanish RIO and was having problems with their Bailey Iron Saturate Glaze having a greenish cast to it. He bumped the amount he used up and it solved the problem. 

[Mark C.]

High purity iron oxides are sold thru most outlets

laguna/axner-https://www.axner.com/ironoxide-red.aspx

US pigments-https://uspigment.com/product/iron-oxide-red-high-purity/

I have used both with same results-I use it in same amounts

Since I'm a laguna person I use them the most.

I have a 50# bag of each including the old standy spanish red Iron Oxide which I still use in other iron glazes

[CactusPots]

4 minutes ago, Mark C. said:

High purity iron oxides are sold thru most outlets

laguna/axner-https://www.axner.com/ironoxide-red.aspx

US pigments-https://uspigment.com/product/iron-oxide-red-high-purity/

I have used both with same results-I use it in same amounts

Since I'm a laguna person I use them the most.

I have a 50# bag of each including the old standy spanish red Iron Oxide which I still use in other iron glazes

I think that is THE RIO available now.  The Spanish RIO is generally not available anymore I believe.  The stuff they are calling natural is what I was getting as brown iron oxide.

[liambesaw]

My supplier sells natural iron oxide and Spanish iron oxide, I have to get the 99% stuff from uspigment 

[Pres]

5 hours ago, Min said:

@CactusPots, thanks for your reply. I wasn't actually thinking of it as a challenge, just curious if you were going to go into your thoughts on glazes as well as the firing. Perhaps we could turn this into a Question of the Week for @Pres? Are you okay with this if I suggest it?

This is and interesting thread in itself, an points out things that I have pondered over much for years.

Often when using older glaze recipes (from the 70's and 80's) I would find that the glaze was not what was expected, and had to test more with oxide additions. It always seemed to be in the iron areas. Good thread here about the way things have changed.

@MinIf you would add a question to the QotW pool about differences in cone 6 vs cone 10 I would hop on it, as I want folks to post in the pool. I can also add a little in my own perspective. Back in the day, trying to find anything definitive about cone 6 was daunting, There were commercial glazes out there from Amaco, Minnesota Clay and A. R. T, but even then their glazes were not as nice as one would have expected, and slow cooling and firing down was really needed to make some of them pop.

@Mark C. I checked Pittsburgh SC, Bone Ash was listed as $45 for 50#

Iron oxide at SC is one of 3, red iron, spanish red iron and black iron oxide. Black is $5 per pound. I have only used the red iron in the shop or at the HS. Maybe I will have to try one or both of the others.

best,

Pres