Using Large Chunks of Clay

[pieceofpizza]

Hi All,

I've decided that my summer project is to build a cob pizza oven. I have managed to source some clay from a local construction site, however it is in large chunks and very solid (see image). Can anyone offer any advice on the best way to work with this. Should I try and smash it up into small bits first whilst dry or get it wet to try and make it more workable before mixing with sand?

Thanks

[devontiger]

Just a thought, I would soak them in water.

I'm sure someone else will be along and offer an alternative..
DT

[oblertone]

Can't see the pic but lumpy clay is no good to anyone; if you leave it uncovered it'll only dry out, so I'd add some water and cover it with a tarp to keep it useable. Tread it to consistency using two parts sand to one of clay by volume, add water carefully bearing in mind that the water has to come out again.fff

pic has now appeared ...?

[downunderdave]

Break it up into lumps no bigger than your fist. Place the lumps on a large plastic sheet add sand and enough water to get the consistency right while stomping over the mix in rubber boots. The addition of straw will act as random fibre reinforcement. Every now and again lift the corners of the plastic sheet to move the mix back into the centre. Doing this with some friends and adding alcohol can make for a fun time.