Jump to content


timbo_heff

Member Since 24 Apr 2012
Offline Last Active Today, 01:20 PM
-----

Topics I've Started

Metallic Weirdness On Pots

29 May 2014 - 01:07 PM

 Here's a strange result:

Used some old pieces of angle iron as grate bars in wood fire (cone 11+)

When opening the kiln there was some strange blue green stuff in the ashes left behind;

Unfortunately the stuff got on pots too:

It seemed to react especially terribly with an iron celadon (Mark's tenmoku with 2% iron)

but also made ugly stuff on shino and even unglazed wares.

 

Wondering if any one has seen problems from rusty metal in a kiln before:

The iron came from an old railroad bridge (1940's maybe)

The bars were rusty on the surface but still dense and heavy.

After the firing it was flaking in big chunks.

 

Could the problem be from just the iron?

I am thinking that some other impurity in the metal vaporized.

Perhaps the iron was poorly smelted in the first place and was giving off something like whatever is in the blue slag you find around old iron processing furnaces ?

 

Www 2
www3
 

 

 


Great Video On African Forming And Firing : Wow!

15 February 2014 - 06:06 AM

Worth a watch !
 
http://youtu.be/52HKSwkI1hs

Flooded Glaze Bucket

28 October 2013 - 01:01 PM

So a bucket of Tenmoku I had outside took on some rain water.

The bucket had not moved in many months. Crystal clear water floating on top of the settled glaze materials.

I poured off the excessive water:

 

Did that change the glaze: ie are there chemical components in the water that never settle out that I have now just poured off ?

 

Thanks!

 


What's Happpening With This Glaze Chemically?

11 September 2013 - 05:58 AM

tn_gallery_12660_647_292029.jpg

Hi,

I have fired this glaze on a variet of clays and woodfired it: (same glaze on pots in my profile pict (longer all locust firing)

The backs are brown/amber probably like it would look in an electric or gas reduction but the face that gets ash (and more heat) turns into a nifty blue/green sometimes with amazing hare's fur effects.

So what is happening chemically on the ash face?

Is the ash adding silica and ergo diluting the ratio of the RIO ( as in a temoku iron reduction moving towards a celadon?

or is it adding oxides that are reacting?

Is behaving differently because of the additional heat on that side ?

 

.. and most importantly: how can I change this glaze to  behave like this all around the things, all the time?!? Less iron, more gerstley /gillespie ?

 

It's from John Britt's high fire glazes:

Custer Feldspar: 44.00 Grams spacer2.gifSilica: 12.80 Grams spacer2.gifWhiting: 17.70 Grams spacer2.gifBall Clay (OM-4): 6.10 Grams spacer2.gifRed Art Clay: 11.10 Grams spacer2.gifBone Ash: 2.00 Grams spacer2.gifTalc: 3.80 Grams spacer2.gifGerstley Borate: 2.50 Grams spacer2.gifRed Iron Oxide: 4.10 Grams

 

Attached File  amb-cup.jpg   500.29KB   1 downloads