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PeterH

Member Since 28 Apr 2013
Offline Last Active Today, 06:27 PM
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Posts I've Made

In Topic: I Might Be Buying A Test Kiln. Paragon Xpress 1193

16 July 2015 - 05:20 PM

When you are using a small test kiln like this do you need to down-fire?

[To replicate the cooling characteristics of the main kiln useed for production firings.]


In Topic: Green Soap And Drape Molds

16 July 2015 - 04:58 PM

Does anybody recommend using WD40 as a parting agent when making slip-casting moulds,

or is it just used for drape/slump molds?


In Topic: My Kiln Keeps Turning Off

06 July 2015 - 06:21 PM

While you are sitting waiting to see if the kiln turns off, it might be worth thinking about power-line glitches.

- do the lights flicker

- if you have an mains volt-meter, does show any variation at the moment of stoppage

- any changes in electric load; either in-house or by other local users

- any evidence of day-of-week effects

 

How precise is the 5:15 figure. +/- seconds or +/- 5-10 mins?

 

PS I'm vaguely reminded of the saga of telephone trunk line that had an intermittent fault -- but only in

the early evening on rainy fridays. It took them a while to figure that one out.


In Topic: Accidentally Left My Plugs Out... My Reds Look Fabulous

19 June 2015 - 08:52 PM

I'm willing to believe in almost anything influencing a copper-red glaze. However I see that Cyote Really Red

is based on a Cadmium inclusion stain.

http://www.sheffield...NT-p/cg071p.htm

 

... which AFAIK are supposed to be pretty insensitive to firing conditions.

 

Maybe Denice's prof had it right, and the glaze surrounding the stain is brighter?


In Topic: Firing Supports For Glazed Work

13 June 2015 - 04:42 PM

A couple of possible relevant quotes on hight-bisque low-glost:

 

from: http://lindaarbuckle...sque-firing.pdf

Although industrial china is often bisqued high (so it can be
supported while being fired to the clay body’s maturity) then
glazed lower (using binders and gums in the glaze to help it
adhere to a body that is no longer porous), studio potters
usually bisque lower so that the work remains absorbent and
easily glazed.

 

from: https://books.google...w-glaze&f=false

... under Firing Cycle for Slip-Cast Objects

 

And a rather ambiguous quote on the process used by Boehm.

from: http://library.uthsc...09/boehm-birds/

Fine Porcelain Creation

The name “porcelain” was given to translucent vitrified stoneware in China by the explorer Marco Polo in the 13th century. He thought that it resembled a certain seashell named genus porcellana because of its high gloss and translucency. Porcelain is made up of a high temperature (2400° F) fusion of fine white clay and feldspar. To make a sculpture like the Boehm birds, the figure is first modeled in clay or wax. A mold is made from the figure (or many molds in the case of complex figures) and a cast is made by pouring the fine porcelain mixture into it. After the lining of this mold has hardened, the liquid center is poured out, and the mold is removed. At this time if the model was made in sections, the sections are assembled, and fine details are added by hand. The figure is placed in a kiln for twelve to 24 hours, then cooled for three days. At this time it is in its “bisque” state, and may be colored and then glazed, if desired.

 

I think that this is saying that a high bique was used (vitrifying the body), and a later

glost stage was optional. Obviously there would be the usually difficulties in applying

underglazes and/or glazes to a vitrous body.

... opinions to the contrary welcomed.

 

Regards, Peter