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jrgpots

Member Since 15 Mar 2013
Offline Last Active Today, 04:34 PM
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Topics I've Started

How Much Does A Refractory Castable Shrink On First Firing?

09 January 2017 - 03:09 PM

The sidewalls of my kiln project are built. The outside of the wall is 4" of hard brick and the inner liner is 4.5" of k26 IFB. The chamber is 30.5" wide x 25" deep x 24" high.

I had planned on making the arch as a monolith from a castable. But I worry that the castable will shrink too much during firing and collapse.

So here are my questions....

1. What is the percent shrinkage?

2. Would it be better to cast the arch in sections, like large bricks, fire the sections in another kiln, then assemble thems?

3. Or anybody know where I can get a good price on #1 arch bricks?

Jed

Very Cool Ulexite Oil Spot Glaze, Cone 6

30 August 2016 - 11:27 PM

I found a very nice oil spot glaze posted on Facebook by Clara Giorello.   She took a cone 10 oilspot glaze, "Daly's oilspot" and changed it to a cone 6 glaze by adding Ulexite.   I had not even heard of Ulexite before, so a google search taught me that Ulexite is a sodium borate mineral.  It is also known as Sodium Calcium pentaborate octahydrate.  It sounds like very cool stuff.  It forms complex crystals that refract the light.  It is known as "TV Stone."   It is similar to Colmenite without the Silica and alumina.  Gersley borate has a small amount of it.  Clara Giorello ground the mineral herself.

 

Her recipe is: cone 6

 

K feldspar           40

quartz                 30

Talc                     10

Kaolin                 10

Ca Carb              10

 

 

add:   RIO           10

          Ulexite       10.

 

 

I tried to find a supplier for Ulexite.  I found an import company that was willing to sell me a metric ton of the stuff.  Has anyone ever used this and by chance found a distributor?

 

Jed


My Kiln Build

29 July 2016 - 08:47 PM

I am finally getting around to build my kiln.  It will be about 16 cu ft in capacity.   the outer measurements are 43' x 43."

Here are the first pics from the project.   More will follow.

 

Jed


How Many Water Colors Besides Cobalt Withstand Firing?

15 July 2016 - 02:41 PM

I have noticed a couple of posts mentioning the use of "cobalt  blue watercolor" as a colorant in glazes and washes. Are there other watercolors that are fire stable that would be usable as washes or in glazes?

 

Jed


Is It Possible To Make A Hydrophobic Glaze?

17 June 2016 - 01:10 PM

I was watching a YouTube video on water marbling/

 

   

 

In it Garip Ay makes water marbling pictures useing oil paints on ink stained water.  He then lays paper over the surface a gets an oil painting transfer.   If one could make hydrophobic glaze, could you imagine what transfers one could produce?

 

1.  Could water be replaced by mineral spirits in a glaze?

2.  Would this mineral spirit glaze float on water?

3.  Has anyone ever tried water marbling with a hydrophibic glaze?

 

Jed