Hi crazy plasterers! Been reading your excellent tips and advice for a couple of weeks and thought i should get involved, so thanks and i hope i can repay the favour in the future. 
I have been rendering a large extension with s&c however it has a bay window that is ply on the outside. The less than compatent builders have left it a bit like a hexagon and i now need to create a perfect curve, can anyone please help as to what i should put on the timber before rendering. I have used expanding metal for small areas in the past but dont think this alone will work for such an area where the render will be fairly thick in places.
Any advice is greatly appreciated :
:

I have been rendering a large extension with s&c however it has a bay window that is ply on the outside. The less than compatent builders have left it a bit like a hexagon and i now need to create a perfect curve, can anyone please help as to what i should put on the timber before rendering. I have used expanding metal for small areas in the past but dont think this alone will work for such an area where the render will be fairly thick in places.
Any advice is greatly appreciated :

