Blue Clay

I have a friend that is going to be building his rocket and thermal mass bench out of local clay in this case it is Blue clay, I believe that I was told there was a major failing
with blue clay, but I can't follow that up with any thing solid ?!? Can Someone weigh in on this ! Thanks, for the Good of the Craft ! BIG AL

Hi Big Al. I was going to post the same thing, I still can find a good answer either. I did see a video on using earth clay for pottery and it looked like grey clay ( blue clay). I am going to get a sample of it and make a cob brick and see how strong it is. I still plan on using fire clay slip on the bricks for the core so it would really only be for the cob portion.
Thanks, I hope to hear a positive answer from someone out there.
Carter

I'd like to know too, any cob I make would be using the locally abundant clay from the Presumpscot Formation.

Et al : Best Answer goes to Fellow Member Larry Ng who provided a link in ' New to Rocket Stoves ' i will ask larry to post a link here ! Big Al
Remember that Blue clay is Bentonite the crap they make speedy dry and kitty litter out of ! A.L.

Ben Plummer : true Fired bricks, fired at the high temperatures of a brick Kiln will lock together the clay/sand content of the blue clays, and make a useable brick!
we are working at lower temps to make cob, I would go with Ernie And Erica's answer, I trust them to always deliver the right, well thought out answer ! Big AL

Ah, I see his link: http://villagevideo.org/products/rmh/scenes/, I'll watch them when I get home from work. Thanks Al!

Thank you. It is great to have so many people out there reading the forums.