I have been fighting a losing battle with a screen porch roof that is
made of aluminum panels butted against each other. Sealants on the
seams last about a year (18 months if lucky) before leaks start
again. Each time I clean the old sealants off down to bare metal with
a wire brush. I have tried the normal latex, silicon, polyvinyl etc
but they all fail. The roof gets full Florida sun so it is UV
intensive and hot.

Any experts have a recommended product? I have not yet tried an epoxy
based sealant fearing how hard it could be in the future to remove
it. The panels are very tight together (no visible gaps) yet water
pours through in spots in heavy rains. Is there a low-viscosity
product that will get between the panels and then expand?