Friday, November 30, 2012

Thickened Slip, Trailing Slip, Joining Slip

9 comments:

Newfoundout Potter said...

Great explanation on defloc! It just hit me that perhaps by deflocculating Mal Davis shino it might stop it from curling and cracking during firing. However I guess calcining some of the clay will work as well, but I never know what change in weight occurs after calcining - so I have to calcine out the correct amount of raw clay and then bisque it and that all takes days. Defloccing could be done right away. Would it work?

John Britt said...

Malcolms is probably already deflocculated because of all the soda ash. The clay keeps it workable but you are right ...calcine half the clay. You can make an estimate by looking a LOI (loss on ignition) which is probably 12- 15% on kaolin. so just estimate unless you have done it once and weighted the result.

For Malcolm's I would estimate a 12% loss and then use Glomax (calcined kaolin) or use some you have already bisque fired.

Eleanore said...

Thanks for this. What is "brushing medium" and how does it relate to this discussion?

Eleanore said...

Thanks for this, John. What is "brushing medium" and how does it relate to this discussion?

Liz Gowen said...

Thanks john for us right brained folks the BEST for thinkening and thinning slip. Did it last week for the first time with darvan 7. It is unbelievable....Liz Gowen

John Britt said...

Not sure Eleanor.

Newfoundout Potter said...

Thanks John for the calcined kao info. Never thought about the soda ash already deflocing!

Anonymous said...

How would darvan 7 work on a clay clogged high school studio sink??

John Britt said...

A little late on the sink. Roto Rooter is about it. I remember one place I worked ...they had to bring in a backhoe because the drain went into a big cement junction station about 12" x 12" x 12" which had FILLED up with clay!