Nerds Vitrification Test

[glazenerd]

A simple test of vitrification for home hobbyist, or serious hobbyists, and production potters. An easy preliminary test to check the vitrification of your clay body. (porcelain shown and #2 stoneware)

 

The Test: Simply drop some red food dye on a un-glazed sample of the clay you are using: fired to maturity before testing. Allow to soak for two minutes: rinse clean with clear water while wiping with a sponge or rag. (wiping, not scrubbing). (clear water, no soaps).

 

 

This initial test will tell you instantly if you are producing a mature body when fired. If it fails at all, then go to the traditional absorption test to verify results.

 

 

Bar 1: mature body, no staining. Make sure the bar is smooth with no pits. (bar tested)

Bar 2  less than 4% absorption. Small blotch not visible on camera, barely visible with the eye.

Bar 3> Cone 10 clay fired to cone 6. Absorption around 10% (not tested)

Bar 4. 14% absorption.     (bar tested with standard absorption test).

 

**All bars fired to 2230F (10 min. hold)

 

Use this simple test every time you get a new clay shipment, or change clay bodies. If they fail, then you need to do the full absorption test to measure exactly what the % is.

 

Nerd

 

Edit: added some wording to clarify the test is done after the test bar is fired to maturity.

[Denice]

Easy peasy.  Did any of your kilns survive the lightning.   Denice

[Mark C.]

food color burns away completely at cone 10 so this is a midrange or low fire deal

did the lighting ruin your kilns?

[glazenerd]

Mark:

 

This test is performed after an unglazed test piece is fired to maturity. A mature body will absorb no, to very little dye. A body with 4-5% or more absorption will. I better reread my post, it somehow is giving the impression it is done before firing.

 

Nerd

 

Denice: looks like I lost an Orton 4.0 controller. Other than that, everything seems to be okay. I know one bolt hit just 50' from the studio, because I saw it.

[Mark C.]

Nerd-it was most likely me as my day was hectic and I most likely missed the details.

You mean ceramics require details? I never figured that.