My windscreen bow is of the old design that has a groove in its rear face & used a round section rubber canopy seal. I have been advised by the factory & the Australian Sling agent to fill the groove in the bow & use the current D section seal. Today I sanded the paint from the groove and prepared the area for applying the filler. I'm using a product that is "a stainless steel and fibreglass reinforced filler". I'll let it set for a day or two before sanding.
