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newmatt

Diy Dry Pressed Ceramic Tile?

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Has anyone tried to create dry-pressed ceramic tiles on a small scale? 

 

The Kiln temps are about the same (don't think it matters that they typically use roller kilns). 

 

The molds would obviously need to be a bit beefier (I can do the calcs as needed). 

 

And there are home mechanic hydraulic presses that could generate adequate pressure for small scale production. 

 

Perhaps the trickiest part is mixing the atomized powder before pressing. 

 

Just wondering if folks out there had tried it and had any experiences. 

 

Thanks!

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I was beginning to wonder if I might be the only person experimenting with dry pressing on a personal craft scale.

 

My interest has been in reconstructing aspects of the process by which china buttons and beads were manufactured from circa 1847 until the mid-1900s. (Prosser process.)

 

Starting point: 73% G-200 feldspar, 23% EPK. Mix the dry powders, weigh out a portion and moisten with a spray bottle to 6-9% water by weight then grind in a mortar.

 

I press in a cheap Harbor Freight arbor press, no hydraulics. My typical ware is around 3/4" diameter. I use an ordinary oilite bronze bushing as a sleeve, and dies either improvised from hardware or machined from copper or bronze rod slugs or cast in epoxy by transfer molding from an original object.

 

The pressed wares can be handled with some care. I sometimes hand drill holes with e.g. #51 drill held in the fingers. Also I smooth off pressing ridges and flaws by rubbing carefully with fingers. Fire at 2350 F at kiln's full rate of rise, hold maybe 20 minutes. They come out quite white.

 

My little 120V test kiln elements only make 2350 a few times so I often add 3124 frit to get more survivable firing temperatures.

 

Exploring one reported variant of the old process, I eliminate the EPK entirely, using G-200 and 3124, and add an organic binder. The old process was reported to use milk, but I interpret this as being casein. I use white vinegar to drop casein from milk then press the water out and resuspend in hot alkali solution (sodium carbonate) and dry down to something between slushy paste and quite dry.

 

70/30 G-200/3124 ad lib the casein, and 8% water will press and cohere, and give a white result around 1900-1950F.

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Erratum: 73% G-200, 27% EPK dry weight. 10mg digital scales are inexpensive and readily available thanks to the gold trade worldwide and the weed trade in many regions. My typical batch is 10-20 grams dry.

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I've experimented with dry pressing small items. Inspired by "A Potters Alternative" i made a frame to capture my car floor jack and several molds to press both damp dust and moist slab items.

 

Damp dust is tricky. I was pressing pyrometric cones so the clay content was low. I think a binder as mentioned would be beneficial.

 

I have talked to a guy online doing this for tiles. His method for producing moist dust was semi dry greenware run through a hammer mill. That's another possibility to keep in mind.

 

Please keep us updated.

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Thanks for all the suggestions!  Great insights. 

 

Question for bny:  you mention

 

Starting point: 73% G-200 feldspar, 23% EPK. Mix the dry powders, weigh out a portion and moisten with a spray bottle to 6-9% water by weight then grind in a mortar.

 

I assume you mean 'grind *into* a mortar'?  Can you give some more details on the mixing process?  And any equipment you use in the mixing/grinding process? 

 

Thanks so much!

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I just put the feldspar and frit as-purchased into a plastic jar and shake to mix. I then tare-weigh a plastic cup, transfer the powder mix into that, weigh with container tare subtracted. I then calculate say 8% of that weight and add that much water with an ordinary misting bottle. Then mix with a popsicle stick and transfer to an ordinary unglazed porcelain mortar. Then use the pestle to mix so that the water is uniformly distributed. The mixture still is a powder but coheres somewhat and may form a sort of cornmeal texture. Scrape it out of the mortar into a sealable container or press now.

 

Nothing special about the mortar - I got it at an art store. You might get different results by milling but I have not bothered. It works quite well without. Mix ratios and temperatures take some experimenting.

 

To get a colored body I dry and grind one or another glaze to a powder and mortar grind dry before weighing in the water. Glazes tend to lower the required firing temperature, sometimes way too much. Fire on something expendable or on an alumina bed. I have not yet tried Mason stains or oxides directly in body compositions.

 

The strangest result was from adding bone meal (nutritional supplement, not calcined bone ash). This gave ceramic foam with a closed glassy surface.

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