Have a look to some shapes that the firm which cast our bloc can do :
Notice than the shape of the impeller is like the bloc of Nicozeg
so you can cast it very easily!
They are specialized in high precision casting copper or anything else you want (we will use EDM too to do the mould in order to have 0.3mm precision for edges fins
). Firm is in Switzerland
and very good contact with them so it will be great for us
Even your WW Cathar is really easy to cast..