[Stoves] Paper Clay

[Crispin Pemberton-Pigott]

Dear Julien

 

Yes, this is standard procedure when mixing a cloy body that has so many dry additives that it will not hang together long enough to fire it. 

 

There are two common solution: pulped paper, often newspaper, and adding bentonite clay.

 

Bentonite has the unusual property of making the mix flow when mechanically worked (forming) but when the mechanical action stops, it goes rigid.

 

Thus adding bentonite (about 5% by dry mass) and paper (1-2%) provides a wat to bind ingredients that would not make a formable, ‘throwable’ clay mix.

 

The LOI (loss on ignition) is not as important as one might assume. Making a porous body can have benefits and disadvantages. Assume nothing.  Porous may be weaker, and have a higher cracking problem due to a drop in tensile strength which is an important aspect of durability. Clay made porous may in the short term appear to be more flexible, but clay is not flexible unless it is toughened (which is quite different from being hardened or ‘strengthened’). 

 

Poorly pulped paper is not much use. Adding a small amount of chlorine will speed it up (capful Jik into a bucket) but time is also important. Plan on 3-4 days soaking and occasional stirring. It really has to be a fluid of fibres.

 

The paper is only for holding it together before firing. If you want a porous body there are better choices. Crushed charcoal is one, wax balls another, powdered biomass, xenospheres above a certain size (recovered from high firing temperature coal ash). 

 

Regards

Crispin

 

 

 

Hello All;

I just found a good reference for "paper clay"
https://digitalfire.com/4sight/education/overview_of_paper_clay_108.html

Has anyone tried this?

I think I will give it a go.

 

Julien.



-- 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/attachments/20160505/b9261dbb/attachment.html>