Wedging: it’s not about air bubbles!

Wedging. Who writes about wedging?

Isn’t it to get the air bubbles out? (NO!) And wedging is one of those zen practices that supposedly take 3 years to learn to do right?

Or, is it, in my experience, to get an internal coil going in your clay so that when you are throwing and you start to center on the wheel, your clay doesn’t fight you and centers up easily?

Why we wedge is something many potters know or have known throughout time but is still something I think should be discussed again; especially for art educators out there.

For years and years – and still! I have wedged “Japanese style”; spiral wedging (pointy end under my left hand, right hand on the fat- butt-end) with the spiral – at the fat end of my clay- running counterclockwise. That is, if you looked down on the fat end and imagined the spiral turning, it would spin into the center going counterclockwise.

Yes, I painted on the clay to try to show the spiral direction- which is counter clockwise when the fat end is pointing up- but when you put it on the wheel- it’s going clockwise!

Then I  plopped that fat end of the clay down on my wheel-head and proceeded to throw American style with the wheel running counterclockwise (and the internal spiral going against that- clockwise) and I would very frequently have to battle my clay a bit to get it centered.

So often,– and especially after I got really consistent and more skilled at throwing– I noticed my clay would just refuse to totally center. It would get this little blip- a wobble, a part that seemed like it simply refused to settle down and let me get the clay all-the-way centered and I knew I was doing everything else right. Even if I coned it up and then brought it down just right, there would be that little blip again that I would end up trying to work around. Or, after I got the walls pulled, I would wonder why my pot would suddenly get some sort of odd wobble in it for no apparent reason.

Why did my un-wedged smaller lumps of clay behave so much better? For a while I gave up wedging anything that came straight out of the bag but for large pieces, it was pretty tiring getting it centered.

Finally, overhearing another teacher at Lill Street mention offhandedly something about the spiral helping to center the clay and, at some other point, after beating my clay into submission yet again and feeling like I was not going to always be this strong, a careful examination of the direction of my coil came the realization that the way I wedge was Japanese (the wheels in Japan go clockwise) but my throwing is western ((American wheels spin counter clockwise)

And it takes a fair amount of visualizing to figure out which way the internal coil in the clay is going once you’ve popped it onto the wheel. The fact of the matter is, it was pointless to wedge my de-aired, pugged clay if I was going to put the internal coil going against the spin of my wheel!

note!!!!

I don’t know how many countless people, students, educators, etc, have asked me, “don’t we need to wedge the clay to get the air bubbles out?” The answer is an emphatic NO!

 

Air bubbles in and of themselves are not a problem! It’s only the moisture* they hold that cause explosions. If something is properly dried, you will rarely have explosions.

So please don’t waste your time or your students’ creative-time wedging clay that has been already de-aired in a pugger- i.e. any commercially made clay- clay you would buy in a box.


This clay has been de-aired in a  pugmill. There are usually no air bubbles in it!

In fact, improper wedging will more often add bubbles and you’ll just dry out your clay in the process.

Simply make sure the pieces get enough drying time and have no plaster mixed in with the clay- that IS a sure recipe for explosions.

So why DO we wedge?

When it’s for throwing**, it’s for getting an internal coil in the clay so it’s easier to center the clay. I do not wedge anything under 2-3 lbs if it comes straight out of the bag,I save that effort of wedging in an internal coil for larger pieces of clay when I would be wrestling to get a piece centered.

Here’s how I currently work: any clay straight out of the bag under 2.5 lbs doesn’t get wedged.

It’s airless and too small to matter. 2.5 -3 lbs get wedged the “new way” trying to train my poor hands to reverse their roles and anything over 3.5 lbs is wedged the “old way” and then flipped over.

Did I find it easier once I flipped my wedged clay upside-down onto the narrow point but with the internal coil now “tightening” when my wheel head went around?……Immensely.

All those old problems disappeared and it was much easier to center. Just recently I forgot to flip a wedged piece, began to center it, felt the blip and realized what I’d done and so I actually cut it off the wheel and turned it over and then it was just fine. What a great illustration of what I’d been learning.

 

And yes, I mentally slapped my forehead for not figuring this all out years earlier!

Oh well, better late than never and since I didn’t figure it out for so long, I thought I’d share what, in retrospect, seems like an obvious fact with all you out there who may have also missed it.

*Why is moisture a problem? Once the clay hits the temperature of water boiling, any water will, in fact, boil and turn into rapidly expanding gas which has no space to expand. The result? An explosion as the gas pushes the clay “out of its way”.

**There are just a few uses for wedging when you hand-build. Chiefly it would be to “even out” clay that had been stored a long time- say one side is a bit drier than the other. When I hand-build I use it to make sure my slabs shrink back evenly in all directions- but just take a look at my blog entry on throwing a slab vs. slab rollers for an explanation of that.

***

And while I’m on the topic of de-aired clay, I had a batch of reclaim that I took to a friend’s house and used their Soldner mixer to get it back in shape. I ended up with 300lbs of porcelain filled with micro-bubbles. I slam-wedged it quite a bit but I could never get out all the millions of tiny bubbles so I tried throwing with it. It was very interesting! I could throw a lot taller with it, The clay was stiffer and a bit shorter. “Shorter” in clay terms means that it is less plastic, it won’t stretch as much. Clay is always a balance between wonderful elasticity and not having floppy collapsing clay. In porcelain, I feel that line is even more delicate.

It was great to make a lot of tall and large things out of grolleg porcelain and I simply avoided pulling handles from it or bringing down wide rims or even making a pitcher spout with that particular clay. I used my regular clay to make handles and they fit the mugs I threw just fine. My other concern was a lumpy surface and I did 2 things; I ignored it and the bubbles seemed to flatten out in the firings and I also took a serrated rib and ran it over the whole surface while I was throwing and then smoothed it again. Neither method was perfect but I used up (and sold the end products) of all 300 lbs.

When I discussed this batch of clay with my friends who had lent the mixer, he had also mixed a batch of porcelain with similar results, a stiffer clay. He quoted a old potter who said “pugging ruined clay”

 

 

This is one of those posts where I would very much welcome comments from potters who will know more about this than I do.

So what are your thoughts and opinions on wedging?

 

 

 

 

 

 

 

 

Mata Ortiz Workshop

I have been a huge fan of the Mata Ortiz pottery ever since I learned of it through a children’s book quite a few years ago.  It’s mentioned in my earlier post about Mata Ortiz  where I write a bit more about the story of this small town in Mexico; I received some pots for my birthday one year I enthusiastically wrote a post  about it.

So, when an opportunity to attend a workshop taught by Eli Navarette was offered at the Northern Clay Center, I was thrilled to attend.

finished pots
Some finished pieces by Eli Navarette

Eli was a really nice guy, open, knowledgeable and helpful. He taught the class in Spanish with a translator. My Spanish was good enough to understand him, ask questions and help translate occasionally.

He started out with a plaster “puki” which is a bowl-like mold that really helps hold the pot’s bottom shape. He made a large, fat “tortilla” out of his own clay, which  he brought from the Mata Ortiz area.

While he did that, he passed around the clay which was very different in feeling from the clays I am used to working with here. It was very plastic and yet, somehow drier and also very strong. He said he mixed 3 types of clay together- his own recipe- one for weight, one for strength and one for plasticity. It was a very effective clay for the kind of handbuilding he was doing. He explained how he and other potters get all the clay from that area and how they prepare it. Basically , they dig it up, mix it with water in a 5 gallon bucket and let the heavy particles and stones and other things fall to the bottom. The excess water rises to the top which they pour off and take out the middle part to use.

They also get all their colorants from that area.  More on that later.

After he had pinched the fat pancake up into quite a large part of the pot – and it was not thick! -he added a coil.

1 Eli adds a coil to his pinch pot

I was amazed because I though he would have to let that bottom part set up for a quite a while until it could support the weight and the action of adding another coil.

2 coil smoothed

But I was wrong, the clay, under the skilled hands of Eli, had no problem supporting the next coil.  After adding that coil he smoothed the inside with a blue rubber rib3 scraping the inside and scraped the exterior with a piece of hacksaw.

4 scraping the outside

thencut the rim off to be even again for the next coil.

5 coil added, top trimmed

Then another coil7 completing coil

 

and voila!  a really sizeable pot all in a very short time.8 finished form drying

While he was working he chatted about how he came to be a potter.

His grandparents were living and working in Mata Ortiz but he was living in Chihuahua (the city) he can remember since he was about 7 years old seeing them working with clay  but it wasn’t until a visit there when he was 22 and had already trained as an electrician that he decided he could  and wanted to make pottery. It took him about 3 years to learn how to do it and now he lives with his wife (also a potter) and 2 children in Casas Grandes about 15 minutes from Mata Ortiz- if you take the new road. Both his brothers are potters, the youngest having started doing it first. He said there are now 3 generations of potters, 600 in all! They’ve been making the pottery there for 50 years. And there are young kids already learning about and working in pottery -that would be the 4th generation.

 

Next up was decorating the pots. He told us he sands the bone-dry pots with 3 grades of sandpaper, ending with the finest grade. I asked him about what precautions he takes to avoid breathing in the dust, a health hazard, and he said he works outside and/or wears a mask.

He then takes manganese mixed with clay- so, technically a slip, not an oxide- and applies it to the entire surface using a scrap of velvet. He said if you don’t mix the manganese with clay it doesn’t “stick” to the surface. Then after that had dried- a matter of a minute or so, he applied a solution to help with the burnishing.

His recipe  for this burnishing solution was very interesting. He puts  5% finely ground Graphite and 5% baby oil into kerosene (90%) and applies that with his hand over the black manganese slip. There was some discussion about using just baby oil or baby oil and graphite and also soap- both of those work but leave considerably more streaks.

Then he  takes an agate, highly polished –sometimes they sand them- but this looked like it was out of a rock tumbler and he said they used that too and begain to burnish.

9 burnishing w:stone

Immediately the surface was a brilliantly shiny black.10 burnished surfaceHe said he puts 3 layers on burnishing each layer and by the 3rd coat is wearing cotton gloves so as not to put any oils from his hands onto the surface. You can see how reflective it is in the  photos. You can also see that there are some streaks- that is why he does 3 layers.

Next he revealed (from under a cloth) a piece he was working on.13 pot in progress He apologized that the black surface was only 2 coats and began to paint some lines with a brush that looked like just a few hairs but quite long. 14 long brush in action he painted on very fine lines. Here are his brushes!12 his tool set

He brought small amounts of his colors with him; white, orange and red in addition to the black.  These are also slips because they are colored clays.

Despite being so shiny, the surface is still absorbent. After he has put on the lines he goes back in with a much shorter brush and fills in  15 filler brushWe all gathered around him to watch him paint, it was mesmerizing.

He told us it takes 3 days to make, dry and sand a pot, 3 days of polishing and at least 3 days to decorate the surface. I think the polishing days are not 8 hours of continuous polishing (though I could be wrong) but that each coat is applied, polished and left to dry. He was very clear about the surface decoration, 1 full day to paint on the lines- with just a few breaks for eating, stretching, etc. another day to fill in all the spaces and a 3rd day for corrections- that is where he takes a rounded tipped  stick and gently rubs off lines that are mistakes.

So each pot is a considerable investment of time.

 

Then we made our own brushes! He had just a little hair for us to use16 brush parts but we were very lucky in that one of our participants was willing and generously allowed some of her beautiful straight hair  to be snipped off and distributed.17 hair donor

Here is how you can make your own brush (and I’m sorry I didn’t take more photos- I was making brushes!)  take a stick, like a small dowel or a fat skewer and sharpen it to a point. Cut a straight groove running out to the point to lay the hair in. The hair –which should be about 2” long at least can be dipped in water as often as you need to make it stick together! Lay it in the groove, overlapping the stick about an inch and wrap sewing thread tightly around it, binding the hair to the stick. Leave out a bit of thread sticking out to tie a knot when you are done. When you get to the tip, do one loop just around the hair to keep it together and then wind back down around the stick, now laying the thread right next to itself, covering the stick end completely. When you get back to where you started and left that thread sticking out, tie a knot. You can use nail polish or epoxy to seal the thread and hold it in place. We used roughly about a yard of thread.

We all made at least one brush and used them on tiles to practice some of the techniques he showed us. I will add a photo of my tile when I get it back.

Lastly we talked about firing and how he fires and how the Mata Ortiz potters used to fire.

In the early days, they would be out in the street and set their pot on an already fired cylinder then cover the pot with something like a large ceramic flower pot or a metal garbage can or something that just fit over the pot to protect it from the fuel. Then they would stack wood all around it, completely surrounding the makeshift saggar and on top of it and light it up. They managed to generate enough heat this way to get the pot hot enough to undergo what is called Crystal Inversion which is when the  clay permanently changes and is unaffected by immersion in water any longer. Before crystal inversion, a pot can be recycled and turned back into a lump of clay just by getting it wet.

I confess it was not clear to me whether Eli currently uses gas to fire his pots or an electric kiln. What was abundantly clear was how amazing his clay was in that it could be heated up quite rapidly and cooled incredibly fast. He had a pot (which I now own!) made by his wife (who was ill that day and could not teach with him)  that we popped into an already warm kiln. The kiln was taken up to 750 degrees centigrade (that’s Cone 012-  1382 Farenheit), left at that temp for about 15 minutes and then cooled within an hour and a half to where we could handle it!18 firing fastWe took it out of the kiln when it was at about 450 and stuck it in front of a fan!  The pot was fired in about 3 hours!  Nothing exploded or cracked or showed any signs of stress at all! Interestingly, the colors were dull when we pulled out the hot pot19 dull colorsbut they brightened as the pot cooled.

 

I think what I love about the Mata Ortiz potters – besides their spectacularly beautiful pottery is that they are working much as their ancestors did. They use simple methods that they discovered themselves. They are always trying new things and sharing knowledge. They work completely locally, using the materials at hand and in doing this, they have dramatically raised the standard of living in their area!