Monday, 6 April 2009

A Jug

I think I can out-procrastinate most people. This pot, I made in about 1992?, I plan to fire it some day.

Builders had started on a new housing development a quarter of a mile away, the digger buckets were cutting into smooth yellow clay... I hooked my trailer up, went to visit, asked for a grab of that clay, and took it home. 24 hours later, I had this. I did fire some samples, this one escaped, it's in a store of largely forgotten stuff, long story.... which I'll miss out altogether.
It's a baluster jug, loosely based on mediaeval stuff, hence the unfinished foot.

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  1. nice looking pot... at first i thought it was pit fired until i looked closer, it's some nice yellowish clay, i bet the other fired up nicely

  2. Thankee, sir. Yes, yellow clay, it fires well.
    There's some under the house I live in now, I want to make pots here, in the basement, how cool it would be if I could tunnel out for my raw materials.
    It's blackly dusty, just part of my made years ago pot archives, awaiting a kiln.

  3. Carbide parts are called "Green" before they are sintered. What are clay or ceramic parts called before they are fired? This is not a quiz; I really don't know the answer. Thanks!

    Nice pot, by the way. You should definitely build yourself a kiln just to fire that one pot!

  4. Funnily enough, unfired clay is known as "green-ware"....
    Carbide parts, and other hard ceramic parts...
    like valves in racing engines, turbocharger rotors,bearing components etc, are fascinating... in my other life, at an international ceramics industry show, I was able to handle such interesting things as ceramic valve springs from a developmental Jaguar engine, bang ceramic nails into a block of oak with a ceramic hammer... (That was just a demo, designed to rid us of our belief that ceramics shatter under hard blows)..
    I have a ceramic kitchen knife, and a ceramic-bladed vegetable peeler.
    Mostly, these things are made by filling silicone rubber moulds with powdered raw materials, then pressing them with isostatic pressure (hydraulic chamber) That way the pressing should be without distortion.
    It's a myth, by the way that only diamond will scratch glass, silicon nitride, boron nitride and zirconia certainly will, with ease.

  5. Yeah, we have a hydrostatic press at work. The largest conventional press we have right now is 125 tons so the big stuff all goes on the hydro and gets machined down before sintering. I guess the biggest carbide parts we make at work are anvils about 6" around and about that tall. They're used to make synthetic diamonds but I'm not sure how. I just press end mill blanks. Millions and millions of end mill blanks. I don't get to do anything cool like making Inconel. If I've got it right, Inconel is made by by V-blending powdered forms of all the alloy's components and pouring the mix into a mild steel tube attached to a shaker which settles the powder under a vacuum. After welding a lid on top, the whole can gets heated to a low sintering temperature and rammed through an extrusion press to densify the powder. Then the can is machined off leaving a round billet of Inconel. That's the only way they can keep the alloying elements from precipitating out. Of course, this is all just a fantasy to me. I just make carbide end mill blanks. Million and millions of end mill blanks.

  6. Aaaah! I used to work with kilns that had inconel tips on the burners, Other parts were stainless, we were forever welding heat-stress cracks in the stainless....
    What's the % size change from the machined state to sintered on the ceramics?


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