Soda Firing With Borax In The Mix.

[terrim8]

I found a nice article about soda firing.   https://kazegama.com/soda/ but I am still looking for a good one that talks about borax (which also has sodium in it).

 

Here are some suggested mixtures for spraying attributed to Gail Nichols :

Here are a couple of mixtures for soda firings: 
#1 
36 Sodium Carbonate 
8 Potassium Carb. 
4 Lithium carb 
3 Borax 
48 Whiting 
1 Bentonite 

#2 
35.30 Soda Ash 
7.10 Pearl Ash 
4.50 Lithium carb. 
50.50 Whiting 
3.00 Borax 

 

The Nichols link didn't work where I took this thread from. Still looking for more articles.

[Magnolia Mud Research]

The Nichols link does not work.  Tweak it please.

 

LT

[terrim8]

Couldn't tweak it - just took the link out. That kazegama kiln is pretty nice too. So far all I am finding is just mentions of adding borax. Even John Britt's high fire book just briefly mentions interesting flashing in the vapour glazing section. The recipes came from an old thread with a bad link. One thing I notice is that authors seem to talk about adding just a small amount of borax. One article says it lowers the firing temperature which I am not interested in. Better colour &/or flashing is interesting though.

Back to google....

[Callie Beller Diesel]

The mentions I've heard came from conversations in real life, not from books or links. I have heard of people using borax or Gerstley to lower the soda temp so you could fire it at cone six, or even earthenware temps. The person making the line of inquiry at the time wanted to be able to use terra sig in the soda, and was concerned that it would burn out at higher temperatures, so she tried the lower temp mix. I believe she didn't like the results of the one kiln load she did, discovered that sig survives high temperatures, and didn't continue with the lower fire. Not a lot of help, I'm sorry.

[High Bridge Pottery]

Looks like it is being used as a flux to help melting/vaporising

[preeta]

 discovered that sig survives high temperatures,

Callie do you know what she meant by survives?

 

the waxy looking surface results survives?

 

the colour survives?

[Callie Beller Diesel]

The colourants are subject to heat and atmosphere, of course, so they will react as you'd expect by changing colour with reduction or oxidation, or burning out if you've used something like a finicky green or a pink Mason stain to colour the sig. If you choose to burnish, sig will loose it's high power shine when fired to high temperatures, but it will still have a nice, soft satiny feel. If you just brush it on without the burnishing, it still has that satiny feel from all the fine particles. If you're adding a lot of sodium to your atmosphere in search of heavy buildup, the soda will tend to eat away a certain amount of surface quality in a piece, especially fine detail-type things. Because Sig is usually a thin layer of fine particles, it can definitely get eaten away in the areas of heaviest exposure. If you're you're doing a residual firing, or just adding enough soda to flash your pots, or needing to decorate items for the dry spots in a kiln, sig can offer up some really beautiful effects, especially because it's often made with ball clays that do fun things.

[janicehill225]

I've wondered that same thing about borax, but was intrigued by it because Britt's book showed that Bauer flashing slip was the brightest, and it has borax. I've had the same trouble finding info on borax and on flashing slips in general.  Another aspect of borax is that it's soluble. That makes it not a great choice for glazes. However the soluble salts will migrate to the surface of the glaze and you might get some carbon trapping with its interesting surface effects.  I don't know if this tidbit helps you, but you're welcome to it.