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Paper Clay And Burnishing, Terra Sig Etc

paper clay burnishing terra

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#1 Danu

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Posted 11 March 2017 - 12:00 PM

Hi all,

 

First off I'm brand new here so I hope I'm posting to the right place :)

 

I've studied ceramics before and it was mostly quite hands on work(ie not much focus on the science of it). I did some work with typical college buff type clay, some large sculptures in heavily grogged clay and some experimental small pieces with paper porcelain clay, which I made myself. All of which was successfully fired by my instructor in a normal electric kiln.

 

It's been a few years and I've decided to build my own gas kiln so I can get back into ceramics. 

 

I've been leaning towards the idea of mixing up my own paper clay and playing around with burnishing/terra sig and aluminium saggars. 

 

But there doesn't seem to be a lot of information about these things in conjunction and information online has confused me,  thus I have some questions.

 

1. I have read that burnishing should only ever be done with earthenware, I've read this several places, the idea being that as a piece shrinks the burnish diminishes. However my understanding is that traditionally burnished wear is often pit or barrel fired, and when reading about pit/barrel firing, I have read that you should only use stoneware, because you need the clay to be "open" to fuming for as long a time as possible, and earthenware will vitrify too fast and "burn out" the colouration.

 

I will not be pit/barrel firing so I will have more control over the tempterature. It seems like with either of these scenarios, earthenware or stoneware, the idea is that you don't want the piece to actually vitrify fully, and this could be achieved with either if you just stop the firing before the temp recommended for the clay body. 

 

So, I'm sure there's something obvious I'm missing here. What are the benefits of stoneware versus earthenware when using these techniques? I will probably try a combination of things, but most likely I will end up burnishing terra sigged ware. Does this make a difference when considering stoneware versus earthenware? The articles in which I read that you should use only earthenware were discussing "true" burnishing, with a stone.

 

2. I've read in the book paper clay by rosette gault(I skipped ahead so I haven't read the whole thing!) that paper clay is great for burnishing and terra sig, however it also casually mentions that the clay will need to be bisqued to a higher temp than normal when using paper clay. When most everything I read emphasizes the importance of low bisque/low firing burnished ware, this doesn't really make sense. So, is paper clay suitable for low firing techniques? Would it be a matter of bisquing the paper clay piece to a higher than normal temp(I think it mentioned 1000-1100 celsius or thereabouts) and THEN burnishing it and refiring at a lower temp to achieve your fuming/colouration? 

 

3. I may also end up doing some raku...I've read a stoneware paper clay could be good for this, would anyone have any paper clay recipe or general recommendations for clays that would be good for experimenting with all of these techniques? For example in one thread a lady pointed out how when using paper clay made with porcelain for raku, the paper burns out at a low temperature so beyond that temp you're dealing with the porcelain alone, which doesn't have good enough thermal shock qualities. However I read elsewhere that with paper clay it is the honey comb air pockets created within the clay that gives it good thermal shock qualities. So I'm thinking there must be a combination of clay with paper that is best for this kind of work.

 

I hope someone here can enlighten me, maybe I've already answered my own questions, but I'd appreciate it if someone with some experience in this area could set me straight. :)



#2 Marcia Selsor

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Posted 11 March 2017 - 03:56 PM

I foil saggar burnished porcelain clay but it isn't paper clay. Depending on what type of fibrous material you are using will affect the burnishing surface.
http://www.marciasel...oil-saggar.html
I got about 5 pounds of very fine cellulose powdered fiber for making paperclip when I was in Barcelona last year from the supplier SiO2.


Marcia
PS I am featured in Rosette's latest Paper clay book.
Marcia Selsor, Professor Emerita,Montana State University-Billings
[http://www.marciaselsorstudio.com

#3 Danu

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Posted 12 March 2017 - 11:36 AM

Ok so you don't find there to be a problem with using high fire clays in burnishing/saggar firing? That of course falls in line with some of the information I've read, and contradicts some.

 

If I could get my brain around it all I'd be doing well, I sometimes try to learn too much too fast, it's highly likely that's what I'm doing right now and it will all pan out in my mind eventually, maybe with some tangible experimentation. 

 

That tip on your website regarding how to tell the aluminium saggars are ready was invaluable, thank you very much! It so happens I've watched a few of your videos on youtube, I loved the one on obvara firing which is actually another thing on my "to try" list(thanks to your video). I don't do pottery so I'll be trying to manage it on some sort of sculptural form, should be fun!

 

I'm going to bookmark your website so I can go give it a good read when I get a chance, I'm sure there's plenty of inspiration and gems of information in there. :)






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