Bricks & mortar

[fourlambs]

Hello, new here so sorry if this has already been asked... I am about to commence construction of the dome (97 cm diameter). and wanted some advice on using refractory cement to mortar the bricks and best mix ratios. Previous experience has shown sets very quickly... I will be using the 'sand dome' method.

Does one need to work with small mixes, or can setting be delayed? All help appreciated...

Regards
Phil