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Geopolymer is a green and sustainable material synthesized by alkali activation of raw aluminosilicate rich materials. In this study class F-fly ash based sodium silicate free geopolymers were synthesized and used for coating application at 60oC. Setting time and adhesion strength analysis were performed using Vicat needle and Elcometer 108 according to ASTM C 807-08 and D 4541 respectively. Infra Red spectroscopy was used to understand the degree of geopolymerisation by observing the vibration frequency of-Si-OT bonds around 1000 cm-1. A gradual increase in adhesion strength was observed with alteration of Na/Al ratio from 0.6 to 1.0. A maximum of 3.8 MPa adhesion strength was produced by geopolymer with Na/Al= 1. Final setting time shows variation with varying Na/Al at a constant water content. It was found that geopolymers gained maximum strength within first 3 days and only partial changes has been noticed in terms of adhesion strength. Scanning electron microscopy of the final product revealed that the formation of geopolymer has occurred without addition of sodium silicate. It can be concluded that sodium silicate free geopolymer has the potential to be used as a sustainable and green coating material for metals protection.