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A Really Strong Clay


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So. I was doing some deep research for a incredibly strong clay body and I came across this pretty vague recipe, I was wondering if anyone could help me decode this (what a challenge  <_< )

 

Stone Body

 

Stone               200 parts

Cornwall Clay   150 parts

Blue Clay         200 parts

Flint                 100 parts 

Calx                    1  parts

 

There  was no firing temperature but "fire hard" 

 

What is Calx, Blue Clay, Stone, and another strange clay I saw. Cawk Clay

 

Any input will be greatly appreciated 

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I have this as file info on blue clay, but have not found any nor used it. Portsmouth and Hookset are in New HAmpshire.

 

Blue Clay

Found where there was much still water and estuaries that emerged after glacier retreat—a few feet of sand, then 20 feet+ stratum of gray & blue clay, blue about 10’ down. The sand, silt and clay were deposited to a maximum thickness of 75 feet. These marine clays are easily recognized by their blue-gray color. Marine clays are soils that were deposited by rivers flowing into the Atlantic Ocean millions of years ago. Marine clays are generally poorly drained, and in many instances are highly unstable, particularly when wet…deposits are generally unsuitable for building sites requiring on-site septic systems and development requiring stable foundations. Brickmaking factories around Portsmouth & north of Hookset used the blue clay for brick, some especially for the fine Boston homes built around 1800. 

Blue clay erodes easily when wet and mantles the underlying hill slopes, making farming possible where the gradient is not too steep. The depositional environment indicated by this sediment is open muddy water between 150 and 100 meters deep. However this erosion can be extreme and result in undercutting and cliff collapse.

A mineralogy study of blue clay in areas near No. Carolina bays found it contained pollen of cold climate vegetation including spruce. Material from just above the blue clay had a radiocarbon date of 10,000 years. Thus the blue clay was deposited during Pleistocene time. There is considerable similarity between the blue clay layers although the bays examined were located up to a hundred miles apart. There may have been a dominant role of wind and wind-driven lake waves in the final formation of the bays as suggested by several authors. The blue clay may have been wind-blown or reworked during the period of ice advance and maximum winds and lake waves (Odum, 1952). The blue layer may be a stratigraphic key horizon marking a regime of cold strong winds and dust over North Carolina. 

A blue clay layer underlies Lake Mendota, Wisconsin, (Murray, 1955), and blue clay occurs in lakes of Pleistocene age in New Jersey (personal communication, Dr. Paul Pearson, Department of Zoology, Rutgers University). Blue clay is found in Maine, also, created from glacier retreat.

(California)…clay may be high in sodium and magnesium. It is a clay soil with an expanding clay called montmorillonite. When it becomes wet, the clay platelets expand like an accordion due to infiltration with water. The combination of a slippery sodium magnesium coating on the clays (absorbed cations) with the expanding clay produces the glacier-like masses of blue clay soil. 

Melts at high cones; use low—try 4-6? May fire green…the color changes in the fireing-the clay does not retain its rich blue color.

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Good and interesting info, Lee. The reference to "expanding" at the end sounds like bentonite, but I can't imagine that much of it in a recipe.

 

Have just looked at Hamer and Hamer, under the entry for Ball Clay. First two words are "blue clay". So I will stop there. But the rest of that entry sounds like your description, Lee. It also says there are many different types of ball clay, so you have to know which one they are referring to.

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