Reputation: -15 Poor
Today, 09:00 AM
22 May 2013 - 15:49
22 May 2013 - 14:16
A Little Off ...
22 May 2013 - 13:54
22 May 2013 - 08:52
22 May 2013 - 00:44
21 May 2013 - 20:44
21 May 2013 - 12:35
21 May 2013 - 11:47
21 May 2013 - 08:43
Posts I've Made
Posted 24 May 2013Oh dear heavens... I want access to a wood kiln so bad! I did a little shino firing at a University class, and loved it to death. About the only thing so far that gets me as wobbly knee'd as Raku.
Yes, Stephen Hill, I like your oxidation surfaces just fine... but talk all you want, it's just not the same thing...
No, it's not the same thing but just as good.
Posted 24 May 2013Never heard of it before but I think the nubbin is a cool idea. Not bad being known for nubbins, super bright glazes and reasonable prices.
Posted 24 May 2013No, man, that's just wrong! You can't ###### throw from a couch!
Posted 24 May 2013Thanks John for sharing your insight !
"So what is the goal for the shinos? Carbon trap? One just fire color? Carbon trap to the max (black shino).... or more subtle mixtures of color and blackness?"
Not doing Davis Carbon Trap (I actually don't care for that look very much) The Gustin Shino I use is pretty white on light clay and quite rich over the 42 especially if thin: Really want to maximize the ruddy flashing and ash effects. But I don't really want the clean white look: funky as possible... so I guess "the subtle mixtures of color and blackness"
I thought you want to oxide on the down fire to brighten up the colors? Wrong?
Shinos have many different faces. So difficult to answer? Carbon trapping is but one of many faces of shino. While I've never wood fired I have spent some time researching . The re are many artist that specialize in shino. Judith duff, has much information on her website, regarding her kiln and firing technique. I really love the variety one can get from, one shino glaze in different parts of kiln. From whites,to reds light reds , purples, greys, spotting, Mixes of...... .same shino with different application techniques, produce differnt looks. How long a glaze sits on piece can affect outcome. Then to complicate further how clay bodies will react with , shino, fire, placement In kiln, firing technique. Hope fully you made notes of clay and glazes. Also note what part of kiln pieces were fired. Lots of photos and or videos may help with the note taking on kiln opening. If you haven't loaded yet maybe you could saggar fire a few pieces.. Unfortunately there are way to many variable in play. To answer your questions. While the glaze says carbon trap ........ Doesn't mean you get carbon trapping, Again much depends of firing and what the kiln gods feeling like giving you. It's the variety of results and beauty of this glaze that draws me to it.
While probably not a true shino in the sense I've been working on a. Cone 6 ox shino with very pleasant results.
sensei. John B. (Yoda). has probably the most experienced in japanese pottery and chajin, that is involved with this site. (If you didn't already know). So if your questions were answerable you have the right source.
I like the way you think.
Please take photos, post with progress.
Yoda! Yes. Yoda is a little better looking but still perfect!
Posted 24 May 2013I use a lot of different clays, but probably the one I use the most is cone 6 B-Mix. I think that's the problem. My reclaimed clay has no clay from throwing water and slip that has been dried.
You likely are right is the is cone 6 B-mix.
One of the problems with using commercially prepared "stock" clay bodies is that, because they are proprietary formulations, the manufacturers will not share the actual recipes. So we really do not know what is in there and what the proportions are. Makes troubleshooting difficult.
That being said, in order to get a cone 6 clay to really vitrify, the usual high fire (cone 9-10) kind of choice of a potash feldspar to supply the fluxing oxides for the body is not ususally going to work all that well. The proportions of fluxing oxides relative to silica and alumina in feldspars is not ususally providing the "oomph" to get the melt active within the body matrix. So to accomplish this task, the usual "substitution" that happens is to use some or all Nepheline Syenite as a partial or full substitution for a potash feldspar contribution in the body.
Nepheline Syenite is a SODA based material. THIS is where the potential issues begin. The potential issue with this is that Nepheline Syenite is slightly soluble in water (great for carbon trap shinos). And as the Ph of the water supply in the clay body changes.... the level of this solubility changes too.
So....... what I am driving at here is that it is possible that the older clay that has sat around a long time wet before use, and then wet formed and then slowly dried, and then picked up atmosphereic moisture when it was "dry", and then had water from YOUR water source (not the suppliers.....which MIGHT be Ph controlled) added to it.... the water chemistry of the re-mixed body is subtly changing as some sodium ions disolve out of the neph sy content.
This will cause the clay to go "short"...... and eventually when it gets bad enough exhibit some thixotropic qualities. So that might be part or ALL of what you are describing. It fits the situation that the beer and organic stuff growing does not help.
If you are not using a splash pan (like I do not) that likely means that you are throwing pretty dry (like I do). With your skill base, I am guessing that you are a pretty qucik thrower..... not working and working and working and working a piece to death. It seems to me that kind of forming profile would NOT wash out a huge amount of the finer particle clay materials to the extent necessatry to cause the shortness. THAT answer does not make sense to me.
Out of curiosity, do you find that if you let the bags of clay you get from the supplier sit around for a LONG time wet, and that the clay exhibits any similar "short" characteristics? Is it more plastic when you just get it than it is a year later (you might not order that far out)?
Thanks for replying, John. What you say about Neph Sy is very interesting and yet something else to consider. Commercial clay like B-mix rarely gets to be more than 5 or 6 months old but I've don't recall noticing any difference in plasticity between bought clay that just arrived and clay that I've had 6 or so months.
If you are game.... try running a coule of FRESH bags of the B-mix thru the pug as an experiment... and see if it "kills" the plasticity. My guess is that it will not.
If it is this neph sy solubility factor........ the longer the clay sits wet... the more the issue will evidence itself. Your accumulated scraps ageing is actually possibly making the matter a bit worse.
Will test it. Thanks much.
- Member Title:
- Advanced Member
- 64 years old
- February 19, 1949
- Lizella, Georgia
- anthropology, tree-climbing, paintball, clay