"jim_in_sussex" wrote in message
om...
Adding some cement to Bonding Coat plaster gives an accelerated set.

Does anyone know:

What are the ideal proportions?

What effect does adding the cement have? - is there an adverse effect,
make the coat more prone to crack, or what?


Don't know. But the cement based plaster I sometimes use in fireplaces
specifically mentions to avoid any contact with gypsum plasters so
presumably there's some incompatibility there.