The Bentone EW story continues.

Yesterday I mixed a glaze with .33% Bentone EW and 200 ml of water. The exact specifics are 300 grams of glaze, 1 gram of Bentone EW, and 200 ml of water. I also added about 4 tsp of CMC solution. 

It worked really well for brushing; in fact it was a little watery so today I am going to try to reduce the water even more -- probably 175 ml. The less water there is, the more glaze there is in the water, and the faster coats build up on the pot.

I'm still pretty amazed by how little clay there is in the glaze, how well it brushes, and how well it stays in suspension. 

Ice Crystal

Today I made some ice in the freezer of the fridge in the pottery shop and came back to find this ice crystal sticking out of the ice tray. It seems very curious to me that something like this would happen. How could this crystal grow an inch out of the water? I did have the ice tray full of water and that might have done something with the surface tension of the water so that this thing would grow. 

Specific Gravity for Crystalline Glazes and Bentone EW

Someone recently posted a question on the Crystal Forum about whether there is a perfect specific gravity for a crystalline glaze. My answer to that is that there might be, but I think this is not the best way to see the answer to the question, "What is the best, most efficient way to apply crystalline glaze to my pot?"

I think you have to take a look at all the variables, learn what part each of them plays, and go forward from there. 

The first thing to look at is how are you going to apply the glaze. The conditions are different if you are going to brush the glaze rather that spray or dip it. I brush all my glazes and so the specifics here are going to be about brushing. But the generalities apply to spraying and dipping too.

Next you have the glaze itself and most crystalline formulas have very little clay which means that they are not really going to act very well no matter what, if you don't do something. But you can do something and the glaze will be fantastic to use.

I have been working with a material called Bentone EW and it looks like it is going to be the only clay that I will need in my glazes, and it also looks like the glaze will be really nice with only .5% Bentone EW. Imagine a glaze with .5% clay which stays in suspension and brushes well. 

According to my friend Andreas Widhalm, Bentone EW is 10 times as powerful as regular bentonite. Bentone EW is what will suspend the ingredients in the water. It's much more powerful than Veegum T or Bentonite or Macaloid. 

I mix up glazes in increments of about 300 grams dry materials. To this mixture I added 1.5 grams (.5%) of Bentone EW, dry mixed with a fork,  and then added 240 ml of purified water and this made a very brushable glaze with the addition of some CMC solution. I think I can actually take out some of the water and have an even better glaze. Next time I will try 200 ml of water. I was able to brush the glaze on much faster than ever before. 

One of the major points is that the more water you have in the glaze, the longer it will take to brush it onto the pot at the appropriate thickness. So, if you are smart, you want as little water as possible so long as the glaze brushes wonderfully. 

Adding CMC will help the glaze to brush well. If you feel like your brush is dragging on the pot, you either need more CMC or more water. Again, according to Andreas, if you want CMC to thicken a glaze use it at a molecular weight of 300 or greater  --- CMC with a molecular weight of less than 300 will thin a glaze. You really need CMC for brushability. 

Finally for each different glaze you will need a measured amount of water, added CMC -- I make mine as a solution, and Bentone EW.

As an upper limit on the Bentone EW, I have a glaze with 2% EPK and 1.5% Bentone EW. I have added about 500 ml of water to get it to brushing consistency -- it also has a lot of CMC  -- and I can brush and brush and nothing happens much except that the pot gets wet. Almost no glaze material shows up on the pot. I applied about 20 coats this afternoon and only got about .005" of glaze and that is not enough. I will have to throw that glaze away as it is useless. Its consistency is actually thick so don't let thick or thin fool you in how much water is in the glaze. 

And I guess that's why I feel like specific gravity is not the right way to look at this problem. Specific gravity actually is used as a measure of solutions and a glaze is not a solution, it's powder hopefully suspended in water, which, I guess, makes it a compound. 

I hope this helps. I would encourage you to keep good notes on how much water you have in each glaze batch, and how well that batch worked for you in application. 

Christmas Carols

Last night I led the Christmas Carols in the Temple and for some reason I had left my guitar in "G" tuning instead of standard tuning. So when it finally came time to start playing, something was really wrong. I strummed the first chord of "Oh Come All Ye Faithful" and it sounded terrible. My friend Mark Billman was playing the cello and I just looked at him like I was in deep trouble. 

There were probably 75 people there and I was on the spot and at first I did not realize that I had chanted our daily morning hymm, the Sri Atma Gita, and that I always play that in this special tuning. So obviously I had to retune the whole guitar and it reminded me of one of my favorite poems, especially with so many people waiting.

The Guitarist Tunes Up

With what attentive courtesy he bent
Over his instrument;
Not as a lordly conquerer who could
Command both wire and wood,
But as a man with a loved woman might,
Inquiring with delight
What slight essential things she had to say
Before they started, he and she, to play.

Frances Darwin Cornford

Merry Christmas everyone.

Wieland Pug Mill -- Part 2

Here are the rest of the pictures. 

This is not a pugmill for someone who has no mechanical aptitude. I have had it apart and while I don't think that it will ever need to happen again, there is no guarantee. It is very, very sturdily built. 

This should go to someone who does not need a whole lot of clay at any one time, but who wants and will appreciate really nice clay. Again this is not a good pugmill for a large production studio because it is very slow. 

I am asking 2000.00 for it FOB Alachua, FL. 

Wieland Pug Mill

I have an old Wieland Pug Mill for sale and it will be an incredible pug mill for the right person.

 

It is a very heavy duty mostly stainless steel pugmill made by a small company in California. Charlie Wieland was kind of a genius/mad scientist who designed and built these pugmills and other pieces of pottery equipment. He is now retired. I think this one is from the 80's and I have had it since the early 90s. It cost 6500.00 when new. 

It has a 2 hp motor and it's very heavy and powerful. The clay that it makes is, in my opinion, better than the clay that I have gotten out of both my Bluebird and Venco pugmills, and is the best clay that I have ever used. It's very compressed and throws very well. You can wedge it but you don't really need to. 

The Wieland however pugs very slowly. When the 4 inch nozzle is on the pugmill, the clay comes out at about 12 inches a minute, so this is not a high volume pugmill. You get incredibly compressed clay but very slowly. 

The pugmill is on wheels so that it rolls around easily. There was a vacuum pump that came with it but it stopped working really well and I bought a  vacuum pump to replace it. It is virtually brand new. 

The clay comes in at the top, is extruded towards the chamber, and then falls through the  vacuum chamber and is finally extruded through a nozzle at the bottom. If you have a good vacuum, the clay is very compressed.

The augers are stainless steel and a material that Charlie called tabular alumina. I never got any rust stuff in my porcelain but there is one place where the clay could touch regular steel.

I could not get all the pictures of the pugmill in this one post so I will post the rest of the pictures in the next post. 

Bison Tools

It has been a long time since I have posted and the flu is one of the main reasons. It just has hung on for so long. Hopefully it is mostly gone. I do feel better and energy is returning.

There is also the fact that Christmas is just around the corner and I have not really done anything in the way of shopping. Fortunately I have been the target of some Christmas shopping but less than the last few years.

Ever since sometime in the 80s I have been using Phil Poburka's Bison Tools. Here is a photo of my first pair which lasted about 12 years. They are on their way back to Phil to have new blades put on them so they will be good as new. 

The bottom photo shows what happens if one of these babies is dropped. Fortunately this one can be fixed, or at least I hope it can. 

There is another one on its way that will not be able to be fixed and will have to have a new blade altogether.

These tools are expensive but they save so much time because they stay sharp even when working with porcelain. You can use them for years before they need to be sharpened. 

See http://www.bisonstudios.com/