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PeterH

Member Since 28 Apr 2013
Offline Last Active Today, 06:09 AM
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Posts I've Made

In Topic: New Here, Have Question About Duncan Glaze Shivering?

Today, 05:12 AM

Hi,

 

Sorry that you are having problems. Can you confirm that your starting recipe is:

Talc         50.0

Ball Clay  50.0

-----

Water                 45.0% of dry amount

Soda Ash           0.1% of dry amount

Sodium Silicate  0.2-0.4% of dry amount

 

... and say exactly what changes you have made to it (e.g. amount of water, feldspar, bentonite, ...).

 

How do you make your wares: hand-building, throwing or slip-casting?

 

Regards, Peter

 

 

 

 


In Topic: Can't Log On Using Samsung Tablet - Help?

22 August 2016 - 02:46 PM

The FAQ is at:

http://ceramicartsdaily.org/faq/

 

It ends with

If none of the above addresses your issue, please send an email to [email protected]

that includes the following information:

  • The type device to which you are downloading. (i.e. laptop or computer, Windows or Mac, tablet or other mobile device)
  • The video player with which you are attempting to open the file
  • Any error messages you receive
  • Type of broadband connection (cable, DSL, dial-up)
  • Method of Connection (router, modem)
  • How long any attempted downloads have taken

 

PS If anybody has an email address for Chantay could they copy it on?

 

PPS Yes, being unable to logon doesn't prevent you seeing http://ceramicartsdaily.org/faq/


In Topic: Ceramic Buttons Necessary For Fiber Kiln?

18 August 2016 - 03:39 PM

I'm not familiar with US suppliers, but at least one supplies ceramic buttons (at a cost).

http://www.axner.com...er-buttons.aspx

 

I hadn’t realised that two-hole buttons had drawbacks, which might be significant if your'e trying to fire as high as you can.

http://community.cer...for-fiber-kiln/

Steve Mills on thu 8 aug 02

We use a 2 inch biscuit (the eating kind) cutter, lute a piece of clay
to the back of the resulting disc, and bore a single hole through that,
in effect a ceramic *blind* button. The *2 holes through the face*
variety can create a heat path to the outside via the holding wires, the
blind variety can't.

 


In Topic: Native Clay, Odd Smell...

18 August 2016 - 03:00 PM

curt:

In your case I would not worry about the smell (unless it makes you physically uncomfortable), although PeterH may be on the right track. In any case, it is highly likely this smell will burn out in the firing. It will for sure burn out if it is organic in origin.

What you really want to know is if this clay is usable.

 

... lots of good advice

 

I agree totally that the smell (and its cause) are very unlikely to affect the physical properties of the fired clay.

Toxicity in another issue, but organics and sulphur compounds are likely to burn out.

 

However I am concerned/intrigued by this -- far from bullet-proof -- chain of logic:

- smelly clay from a pool

- anaerobic in nature

- sulphides present

- lower than normal pH (more acidic)

- clay more flocculated than normal

- plasticity of clay reduced

- usability of clay reduced

 

Purely top-of-the-head thoughts from somebody who hasn't been there, but just maybe food for thought.

 

If it is possible I would try to collect some clay from a dryer environment (just a test sample) and check for:

- smell

- settling properties

- plasticity of a treated sample

If the properties are different from your smokey clay, then maybe the choice of location is significant.

[Probably only worth doing the 3rd if the 1st two are different?]

 

PS I initially "sort of assumed" that ageing an anaerobic clay would remove any problem. I now get the

impression that the sulphides (with bacterial assistance) oxidise to sulphates, and things become even

more acidic. [cf acid sulphate soils]

 

PPS last and by no means least

curt: and if it is really clay and not silt (which is larger than clay particles) than you should be able to produce some terra sig with it with proper processing...

If you have a deflocculant about, this sounds like a good thing to try, at least as far as seeing if a significant "colloidal" layer forms.

Obviously if the sample is acidic you may need more deflocculant than normal.

- If this doesn't work, can your sample really be similar to that used for native pots?

- If it does work, maybe your current sample gives an over-flocculated suspension?

 

 

 


In Topic: Native Clay, Odd Smell...

17 August 2016 - 06:23 PM

Just a wild guess. Recovery from a scummy pond makes me wonder if the conditions were anaerobic.

IIRC this tends to result in the presence of hydrogen sulphide. Residual memories of long-ago chemistry

classes suggest that the smell in low concentrations can be a lot more subtle that simply "bad eggs".