F1 F2 & F3 are multi purpose insulation materials manufactured from fine, medium and course weave phenolic cotton materials. They are strong and tough with very good wear resistance and as such are good for general mechanical applications. F1, F2 & F3 show good electrical properties.
These tend to be superior in the finer weaves. In general the medium and course weave grades are used for larger more rugged components. The finer weave grades are chosen for their superior machined finish, higher dimensional stability and improved strength in thin sections.
P1, P2 & P3 are multi purpose insulation materials manufactured from phenolic paper materials. These materials are strong, rigid and very economical. Choice of grades depends upon voltage or other insulation requirements. P1, P2 & P3 are not normally used in applications where rigid non metallic insulation materials are required. The grades all exhibit low moisture absorption.