I know this is another of those elementary things I am just missing.

In the detail section of my report I have a field [Duration]. Duration represents seconds.
In the report footer I have a the sum of Duration, or =Sum([Duration]).

I would like to add in the Detail section of the report an expression which will take [Duration] and convert it to hh/mm/ss.
I would like to add in the Report Footer section of the report an expression which will take my sum of [Duration] and convert it to hh/mm/ss.... keeping in mind, this may be over 24 hours.

Suggestions?