Here is Proof that Thicker Paste forms Thicker Glaze

Make a ball of Egyptian paste then cut it into two equal halfs; take one of your halfs and divided it in half again. So now you have one half and two fourths made from your original ball of Egyptian paste. Taking one of your fourths and rolling it into a ball and joining the remaining fourth to the half yielding two balls of Egyptian paste, one being three times more volume than the other. Press these into a button form, dry and fire them to cone 04 (approximately 1000°C) and now you have what is pictured here.

The button on the left is one third the volume of that on the right. Both buttons started with the same surface details. However the larger one developed so much more glaze that it obscured /flooded the texture. Photographing on a dollar bill should give you perspective on both size, detail and color.

These two buttons were fired along side one another in the kiln; the reason that is mention is that placement in the kiln also effects the glaze. However, this is a subject for another post later on. The unfired Egyptian Paste or 'greenware', as potters call it, shows an even deep texture than the fired ware.

For now we have our first little fact for the behavior of Egyptian paste. Fact #1. The larger the volume of paste, the thicker the glaze. Well that is one fact down, 99 more to go!

Small Hole Beads

Looking at the faience from ancient Egypt, one has to wonder how they crafted such little beads. All of my attempts at piercing tiny beads, ended with a crack that was larger than the hole. How did the ancient Egyptians do it?

It can be done; we know that for certain by examining museum pieces, but how? What did the ancient Egyptians have to work with? Skill, a lot of time and bronze tools is the answer to that, but not much else.

That's what got me to thinking the answer had to the simple. Knowing that nothing organic survives at 1000°C (1800°F), a few pea size balls of Egyptian paste were threaded onto pine needles. These were dried leaning against the wall of a ceramic dish, in order to let it dry from all sides and place it into kiln without disturbing the glaze surface. It was fired pine needles and all. Much to my surprise, this experiment worked splendidly!

The Thicker, The Glossier

Stands to reason that larger/thicker pieces have a Glossier finish, than smaller ones. Does it not? A thicker piece takes longer to dry, yes? With longer drying time more salts wicks through to the surface, agree? The more salts on the surface the thicker the glaze forms, right?

The two figures in the image here are constructed from the exact same clay/Egyptian paste mix. They dried next to each other; they were fired along side one another in the kiln. Mason stain, pansy purple, was added to the basic mix, 2.5% by weight. You can observe here that the thicker the glaze the bluer it appears. On the bottoms where no evaporation occurs their color appears identical.

Lots of cracks developed in bigger pieces as they dried. Possibly, the introduction of sand or grog would alleviate this cracking. Of course additions to the basic recipe might also affect the color. The addition of grog would also improve this clay's ability to stand up. There’s always more experimentation to be done.

Well, That Did Not Work So Hot

When you're experimenting not everything works. In fact very few things are successful the first second or even a third try. But there is useful information in every try. Recognizing it might be tricky. More important you find ways to refine your experiments for the next trial.

Reasoning that ancient Egyptians probably did not have nichrome wire to fire faience on and yet they turned out exquisite articles made from Egyptian paste; they must have some technique of keeping the glaze from sticking. Probably something very common in their environment. Perhaps it was fired on a reed or stick. A burn match will hold its shape, it may even support the weight of something as little as a bead. It may sound silly now but it was given a try.

A number of organics were tried, bamboo reeds, little wood twigs, leaf stems, hey even spaghetti was employed. The spaghetti failed miserably; it cracked the beads half lengthwise as you may clearly see in this image here. The bamboo reed burnt away leaving just the tiniest whisper of ash; however when the bead fell away it hardly stuck to the substrate it all. We may have discovered something here.

It's worth trying again for other reasons too. Some nice uniform bead holes were formed using this "technique". Also noticeable is when spanding the kiln furniture the beads stayed in place if they were long enough. Definitely worth trying again!

Bluetooth Beads!

Continuing with the excitement from the last kiln firing here's an image of something that went right. Turned out well both front and back. This is a rather simple bead to make just time consuming. An IBM Selectric typewriter element is used to give a sort of modern hieroglyphics; you can see the individual characters impressed on the beads if you look for them. Too bad there is not a Greek character ball in the studio texture toybox.

With a few spacer beads the Faience beads are strung on monofilament/fishing line temporarily, just to get an idea how they would look. They sure would be lovely strung with copper beads. We will call them “Bluetooth Beads”!

The bottom/backsides of these beads have no glaze on them, because there was no evaporation from that side, and therefore no salts could accumulate on the surface forming the glaze. That is the efflorescence in action that was mentioned in an earlier post. They were fired sitting flush against the kiln shelf. An aluminum hydrate shelf primer kept sticking to a minimum; sticking really wasn't a problem with this Egyptian paste recipe. The unglazed portion feels like a fine grain sandpaper or etched glass. The glaze side is a rather matte glaze smooth to the touch.

Silica Sand in the Mix: remarkable results

Anitra

I'm not sure that I can post a picture with a comment on your blog... but here are some my first fired attempts (size of small disc shapes 0.5" or 10mm). The three grey ones at the top are unfired, the blue ones fired up to 1000 C (1830 F) and held there for about 30 mins. Do feel free to use the picture yourself and comment on it in any way you like.

There are several obvious things to my mind:
1. the paste is almost unworkable, so these are the most sophisticated shapes I could make
2. I probably handled the dry pieces more than necessary so may have adversely affected the surface
3. The grains of sand have not really welded together, so the fired piece is not much stronger than the unfired - maybe a higher temp or longer soak would have made a difference, maybe not...

I'm looking forward to experimenting with the finer stuff.

There is certainly clay in one area of the salt marsh... another avenue to explore as you say...

Alan


Say Alan, it is truly remarkable that you were able to do anything at all with your “sandy mix” of Egyptian Paste. They have a nice surface texture. How you were able to hold it together is testimony to your skill. You are bound to turn out wonders with the finer mesh silica in the mix.
As you can see I've posted your letter. I read that I can make you part of this "Blog Team"; therefore you will receive an invite to be an author shortly. You may post as often as you like just keeping it about Egyptian Paste of course.
-----------Anitra

Firing Egyptian Paste, Houston We have FAIENCE!!

Opening a fired Egyptian paste kiln is one of the more exciting occasions in the studio. You always know you will get some little gifts. If you're like I am you will have an experiment or two running. So there's going to be some disappointments too. I really shouldn't call them disappointments; we need to think of them as learning experiences. There's serendipity too!

This last Egyptian paste kiln firing was no exception to the excitement rule. The paste goes in the kiln so nondescript and comes out so vivid. There were some surprises. Just 2.5 percent pansy purple mason stain yielded a much deeper color than expected; I can cut that down to 1% in future firings. The base recipe for Egyptian paste without colorant came out a pale gray, nearly white. I imagine with the addition of tin oxide or zinc oxide a true white may be obtained. That is the basis for another future experiment. I had a few experiments going on in this kiln that will be covered later on. For now, I can say that over all I was pleased with this firing.

My bead island performed marvelously as expected. The beads came off quite easily. Of course there was a layer of shelf primer on the peaks to keep the bead holes from sticking. Painting them with a layer of wax resist will keep the salts/fluxes from being absorbed by the clay of the island. In this firing, I neglected to do this wax coating and yet there was little sticking.

This firing was cone 06, that's about 1800 Fahrenheit/1000°C. A cone firing is a measure of work done by heat rather than temperture; the cone is formulated to melt at a certain temperature so when it bends the kiln is said to have reach temperature. Were I firing by pryrometer I would probably have to hold the kiln at temperature. Most potters just fire up to cone 06 then shut the kiln off. In my case, the “kiln sitter” shuts the kiln off. My next firing I'm going to try taking the kiln up one cone hotter to see if I can get the paste to flux a little bit more. More variation in the color would be nice. The the beads look a little too controlled, not enough like the ancient Faience. Even so, some of the ancient Faience is this turquoise.