I found a great fiberglass cloth for tool making. 10oz plain weave from www.fiberglasssite.com
Hexcell Style #7500 ( soft silane coating )
It takes to corners and abrupt radi very well, all the while laying flat on the surface with no air pockets. It has a nice thickness to the cloth so you can build up the tool thickness to .187" with i’d say… 8 to 10 layers of this f/g.
I am using it now for an epoxy mold.