tag:blogger.com,1999:blog-12223283.post114351323084588829..comments2009-02-20T19:50:23.894ZAdrian Bowyerhttp://www.blogger.com/profile/17595509188999219420noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-12223283.post-1143573954247152542006-03-28T20:25:54.246+01:002006-03-28T20:25:54.246+01:00Kaolin is probably the form of clay we'd use and your points are well-taken about price and reactivity. <BR/><BR/>I know that calcium carbonate used as a filler tends to make the mix easier to extrude. I'm not sure what the effect of using kaolin would be. The reference I found about it talked only about improvements of processability.<BR/><BR/>http://media.wiley.com/product_data/excerpt/41/35273105/3527310541.pdfplaasjaapiehttp://www.blogger.com/profile/00240780042458014636noreply@blogger.comtag:blogger.com,1999:blog-12223283.post-1143568322745276372006-03-28T18:52:02.746+01:002006-03-28T18:52:02.746+01:00Have you thought about using aluminum silicate powder instead? It's even cheaper than marble powder, easier to manufacture and more chemically stable (no reaction with acids, a big problem with CaCO2) I've got about a million and a half tons of the stuff in my front yard (AlSiO2 is also called "clay" )The Guyhttp://www.blogger.com/profile/12623342498696677919noreply@blogger.comtag:blogger.com,1999:blog-12223283.post-1143520294063670702006-03-28T05:31:34.063+01:002006-03-28T05:31:34.063+01:00I know a little about piston-based extruders, as I worked for a concrete pump company called AFD many, many years ago. I think they've gone under now, but here's basically the thing we used to make:<BR/><BR/>http://www.auscrete.com.au/piston_pump_design.htm<BR/><BR/>But it looks like the extrusion you're doing manually is shaping up very well.<BR/><BR/>Vik :v)Vik Olliverhttp://www.blogger.com/profile/08344580890636084746noreply@blogger.com