So Trina ... What about the Great One huh?? I'll see two of your Orrs and raise you a Gretzky.
This reminds me, when my mother was a little girl growing up in the Detroit area, Her older sister would take her to hockey games, coming out of the arena one night she all of a sudden got caught up in a large crowd and didn't know what was going on, until she looked up at who was walking beside her Mr. Hockey himself Gordie Howe. Of course he was very nice about the hole thing.
I live in Michigan and speak fluent Canadian because I grew up on: Mr. Dressup, The Friendly Giant and the Beachcombers (Channel 9), I often trade beaver pelts, duct tape and the occasional pasty with them. -not pastie
Has this topic gone askew....By the way, type askew into the Google homepage and watch what happens.
I think it may depend on your definition of 'strength'. High fired clays may be harder, but not necessarily stronger when impacted or stressed. If I understand Pete's test method, they were taking bars of clay, laying them across a gap, and snapping them in half via pressure in the middle? In that case, it makes sense to me that the earthenware was the winner. Under this method of testing, the earthenware probably has more flexibility and can deflect more than the stoneware before breaking. The stoneware/high fired clays, while tighter and harder, are likely more brittle under this type of test, and can't deflect much at all before giving way and snapping.
I don't think you're right about this. I think "hardness", too, depends more on composition of clay body and that clay body being fired to maturity than on temperature. I'm almost certain a cone 6 porcelain fired to maturity is just as "hard" as a cone 10 porcelain fired to maturity and, after reading about Pete's test, I would guess that a cone 04 earthenware fired to maturity is just as hard, if not harder, than any cone 10 clay.
Maybe Matt can pull up something about hardness or, at least, chime in here with his opinion.
As far as the red earthenware goes, the redart recipe doesn’t look like it has a lot flux in it, so I would think that it is porous like other red earthenware. I wonder how much flexibility does play a role, he did mention a cone 1 firing didn’t make it stronger, which I assume means it was just as strong. Could the high iron content of red clays have something to do with the results?
About difference between cone 6 porcelain and 10, from what I have read there are more and longer mullite crystals at higher temperatures, it would be nice to know how much of a difference it makes. Here is an interesting paper on the subject that seems relevant.... Mullite development
It would be interesting to compare a vitrified 6 and 10, under glazes with similar compression (or how ever you would do a fair comparison), then put them through a series of tests. Until then, I'll rely on everyone’s real life experience, because I only fire to 6. I'm really only curious though, cone 6 has proven to be strong and durable enough for my needs.
On a similar subject, Matt and Dave’s clays have published results on there website in the science section, showing how a cone 6 gloss glaze, using the right amount of boron, can be more durable than a 10.
I guess I do everything-breaking the rules. 1)I set up my cone back so that it sets parallel to the peep hole, perpendicular to the wall. 2) the cones are set at opposite angles along the length of the coil of clay. 3) I set the cone very close to the peep hole so that I can see each cone when loading the kiln. 4) I pack a kiln way to tight to see an element on the other side of the kiln.
Thank you for the alternative info, important points.