The purpose of shuttering oil is as follows
1. To avoid friction and bond between the concrete and form work for easy stripping without damaging formwork and structure.
2. To enhance the life span of formwork.
3. To felicitate the de-shuttering as smooth process
4. To provide smooth surface to the concrete after de-shuttering.
5. When u apply oil ensure that, accidentally it should not applied on reinforcement. it will result no bonding between concrete and reinforcement.
Do not over oil the shutters and do not allow oiling the shutter after fixing reinforcement in slabs and beams.