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PeterH

Member Since 28 Apr 2013
Offline Last Active Today, 03:48 AM
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Posts I've Made

In Topic: Weird Liquefied Slip ....

26 August 2015 - 08:37 AM

What would be the results of adding too much SS?

 

See the first graph in

http://digitalfire.c...erview_324.html


In Topic: Lichen Glaze "peels" Off When Applied

26 August 2015 - 07:24 AM

The moisture in the first layer of glaze/slip and the body is key here. You either apply the next coat while the under layers have enough moisture that the two dry together, or you wait for the first to dry, so the rehydration of the under layers doesn't push it off of the body (notice how clay rehydrates well when wet or dry, but is resistant to moisture in the leather hard stages, similar interaction).

 

Thank you, that makes a lot of sense. Peter


In Topic: Lichen Glaze "peels" Off When Applied

24 August 2015 - 01:43 PM

I remember seeing a demo on 2-part raku smoke resist by Gabriela Koch many years ago,

applying the two layers by by dipping. Following a question from a member of the audience

she said that the top layer flaked off unless it was applied

- either less than about 20 mins (or was it 40?) after the first

- or after 18hrs or so

 

It just might be worth doing a test applying the lichen glaze after 18hrs or so.

 

PS I never found a rational explanation for Koch's experiences.


In Topic: Very Fine Sheets

23 August 2015 - 08:20 AM

What I am trying to make it an experiment. I heard that using terracotta clay there is a way

to cool the interior of the vessel  because of its permeability to the water and the evaporation

of the water requires energy that lowers the temperature of the outside and inside of the

container. I want to experiment in a different way with this phenomenon. I am curious,  that’s all.

 

The idea certainly works. However those instances I've seen have been made out of

quite chunky pottery, so I'm interested in why you are looking at thin sheets.

 

[The need for evaporative cooling in the UK is quite low. However do I remember UK

milk-bottle and butter coolers from my childhood (when milk was left on your doorstep,

and before fridges were common.).]

 

Peter

 

PS I did a few quick googles

 

The traditional Spanish ‘botijo’

http://www.notechmag...04/botijos.html

... includes an experiment keeping water cool in an oven, and a ref to an old technical paper.

After 7 hours in an oven at 39C the inside water was at 24C. Wow!

 

A modern product

http://www.stwerburg.../terracool.html

... note the use of a glazed saucer to stop the water leaking onto the supporting surface

 

Architectural building-scale use

http://www.phdc.eu/u...ic_01-06-09.pdf

 

PPS

AFAIK paper-clay seems to be the body of choice for those making really large, really

thin sheets, often 'cast' on plaster from paper-slip. (Paper-clay dries more evenly, and

has greater green strength.)

 

 

... afterthought: I assume that there would be problems with long term use in hard-water areas.


In Topic: Bone China And Cnc Machine

20 August 2015 - 08:56 AM

You may be interested/amused by:

http://community.cer...thin +porcelain

 

Don't know the status of 3D ceramic printing, but there is/was at least one firm

selling expensive 1-off 3D printed lamps in nylon:

http://n-e-r-v-o-u-s...uct.php?code=99

 

More expensive 3D printed nylon lamps:

http://www.within4wa...338&category=52

 

Peter