What can I use to glue an aluminium rail to a marble countertop base for a sliding door?

You can use Poxipol. Before using it, make sure the surfaces to be joined are clean, dry and free of grease or rust. It is recommended to sand very smooth or shiny surfaces.

It is very easy to use—just follow these steps:

1) Measure out equal parts of each component. Make sure to apply a bead of at least 2 cm of each component.

2) Mix for approximately one minute or more, until you obtain a uniform colour.

3) Apply the mixture to one of the surfaces to be joined and hold the parts together for 10 minutes.

Bear in mind that the product hardens in just 10 minutes, but reaches its maximum strength after 24 hours.