Jump to content
Sign in to follow this  
Babs

Spodumene

Recommended Posts

Was reading last night that spodumene was used to make a toasty coloured clay body but required quite a percentage to do so.

I wondered if anyone has done a wash on clay using Spodumene , in a similar manner to that of the soda wash?

 

Share this post


Link to post
Share on other sites

yeh, see, someone's done it!

Thanks for the links Peter,  no need for prescriptions, just breath.......in my shed during glaze mixing. Not to be practiced at home..

Underneath a glaze may give some life??

Share this post


Link to post
Share on other sites

Spodumene can be used to make a toasty clay body, but it's not that simple. It will dramatically reduce the shrinkage rate of the clay, and make glaze fit a real problem. A.R.T. Clay used to make a body called Orangestone, a beautiful toasty orange color. Lots of spodumene. The shrinkage rate was around 6%. Most glazes wouldn't fit it- many would shiver or do other weird things. Most people just used it raw for sculpture or jewelry.

 

Flameware bodies are often high in lithium because it reduces the expansion rate. I've heard of flameware bodies with 0% shrinkage, or even expansion.

Share this post


Link to post
Share on other sites

As Neil says, spodumene has been used to develop flameware bodies, and from talking to potters who went that direction, glazing was a problem.

 

Another reason why a spodumene wash would not be quite the same as a soda wash in terms of application is that soda will dissolve in water (and penetrate the clay body) but spodumene will not.

 

I would echo the suggestion to try a slip with a little spodumene, if you want to see how it affects the surface. 

Share this post


Link to post
Share on other sites

Thanks Neil and Ray. I will try it on the unglazed bottom third of some bowls to see the effect, I'll overlap the glaze a little at the meeting point to see what happens.

The insolubility of the Lithium would be why the recipe in one of the links above calls for bentonite to help with the suspension

Share this post


Link to post
Share on other sites

Not using the slip , Neil with the non shrinkage info has scared me off, the slip may just drop off the pot right?? The amount required for a colour change is said to be quite a large percentage so I'm going to go with the wash applied just before glazing.

Share this post


Link to post
Share on other sites

Babs, if I were experimenting I think I'd try a very thin slip on a test tile to see what happens-- maybe equal parts ball clay and spodumene as a starting point.  If it pops off, you'll know immediately that it won't work, and waste no time with it.  Or I might try a combo of Alberta slip and spodumene.  My favorite high iron glaze in oxidation uses lithium to push it toward the red side of the spectrum.

 

I really like slip, because it allows you all sorts of surface effects that are difficult to achieve otherwise.  As an example, for many years I used a simple white slip on porcelain.  The slip contained a high level of titanium.  I used resists and carving to expose the raw porcelain underneath.  Over this I used glazes that tended to develop microcrystalline surfaces if cooled very slowly.  The effect was clear limpid color over the raw porcelain, and frosty crystalline surfaces over the slip, when fired at a normal cooling rate.

 

Whatever you decide, let us know how it works out.

Share this post


Link to post
Share on other sites

Babs, if I were experimenting I think I'd try a very thin slip on a test tile to see what happens-- maybe equal parts ball clay and spodumene as a starting point. 

 

I just read a report from someone yesterday that said he tried equal parts like that, and the test piece expanded 2 inches and stuck to the wall of his kiln. Even at cone 10 the clay wasn't hard- said it felt like cone 10 bisque. As a very thin, watery slip it could be interesting.

Share this post


Link to post
Share on other sites

Yeah, I think it would have to be very thin to have a decent chance of working.  Maybe add some flux if it's too chalky a surface.  Of course, at some point you have a hard engobe or maybe even a glaze, if you continue down that path.

Share this post


Link to post
Share on other sites

Neil are you really trying to scare the beegeeebeees out of me? 2" HAve to be using it as a clay body ,right??

I'll try the thin slip on leather hard and also the wash, like the idea of slip as a textural thingie.

Share this post


Link to post
Share on other sites

Passed on in case you have bubble-trouble with a high-spodumene glaze.

 

https://digitalfire.com/4sight/material/spodumene_1287.html

Some types of spodumene do contribute to the formation of bubbles in the

glaze slurry. You can wash spodumene before use to alleviate this issue

(mix it well in plenty of hot water, allow to settle overnight, pour off the water

the next day and dry it).

 

Share this post


Link to post
Share on other sites

The spodumene supplied by the Greenbushes mine is a fine sand that is 88% spodumene and 12%silica.  I fired a little bowl of it to about cone 7 and it converted to beta spodumene, puffed up and turned into a fine pink powder. It did not melt at that heat and didn't even fuse to the bowl it was in. Spodumene has one molecule of lithium oxide to one molecule of alumina to 4 of silica, so it is like feldspar, but with a lower proportion of silica. Spodumene has a negative co-efficient of linear expansion. It doesn't shrink when fired, it gets bigger.

 

Lithium carbonate is Li2CO3 and is slightly soluble. That is what you need to spray on the raw clay to get a sheen.

 

"Ceramics Monthly" of February 2015 has an article on spodumene.

Share this post


Link to post
Share on other sites

Here are some small pots thrown for tests. I. soaked the spod, and there were bubbles as a poster mentioned.

I then , non scientifically, as I am not really pursuing this other than interest arising from something I read. mixed it with the throwing slip from the pots. I applied this as they came off the hump.

Some areas, thicker app. the spod clay mix was quite glossy.

post-21244-0-57837900-1454106303_thumb.jpgpost-21244-0-93352900-1454106320_thumb.jpgpost-21244-0-03190100-1454106362_thumb.jpgpost-21244-0-17978500-1454106391_thumb.jpg

post-21244-0-57837900-1454106303_thumb.jpg

post-21244-0-93352900-1454106320_thumb.jpg

post-21244-0-03190100-1454106362_thumb.jpg

post-21244-0-17978500-1454106391_thumb.jpg

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×

Important Information

By using this site, you agree to our Terms of Use.