Sand form for dome

[ClayWood]

Wondering if I should mix up a weak sand/cement mix to get a hard enough form to work with but still be able to break it up and get it out. If anyone has some advice it will be appreciated.

[UtahBeehiver]

David S has posted some recent tip on sand form mix.

[david s]

To save on the quantity of sand required you can fill the centre with something else like polystyrene boxes or plastic bottles. The sand should have around 8% water. I think powdered clay is used to help hold the sand together rather than cement. Add it only for the outer couple of inches and mix it in dry before adding water unless the sand is already damp. I’d say at around 20:1 addition.

[ClayWood]

Ahh powdered clay, didnt think of that one. Cheers mate ill give it a crack. Thanks