What should I use to provide a water repellent top-coat over an already painted balcony handrail? To help the water to bead and run off. Thanks.
If the handrail is perfectly level and flat, then I believe you'll have trouble trying to get water to run off it. You might find a product to assist with the water beading, perhaps similar to what we use on car windscreens. However, without a slope, the beads will sit there.
Are you finding the water sits there for an extended amount of time after rain, and it concerns you? Or is it just more for convenience, as the handrails can't be lent on after the rain?
Thanks. Yes just for convenience and also to hopefully protect the paint.
As long as the paint does not have any cracks or defects, having the water sit on the surface will have no effect. All exterior grade paints are designed to have water sit on them for extended periods.
You might like to consider keeping a squeegee in a handy location near the door, a quick wipe down would remove the water if you need to use the balcony.
Let me mention @TedBear to see if they have any suggestions.
Thanks for the mention. I agree with your own comment @MitchellMc as I don't know of a product that would provide a permanent coating.
Perhaps spraying the handrail with a product to break down the water's surface tension, such as Rain-X Repellent Treatment for car windscreens, available from car product suppliers would help...
(I haven't tried it for that use, but if it works on the tough environment of a windscreen, I imagine that it should last a while on a handrail.)
It isn't a permanent coating though, so it would need to be topped up occasionally..