First step it to print the handles! I used white ABS with an UP! 3DP.
The STL Files are below.
Dumbbell moyen (part 1 and 2) is for 83.75 mm diameter cans.
Dumbbell small is for 73.25 mm diameter cans
*Note that not all printers print equally and that different materials wont shrink the same way. If you use a different printer or a different type of plastic, you might have to adjust some settings to get a perfect fit.
If you are having difficulty getting a good resolution with your UP!, I suggest you also build this box as showen in this instructables :http://www.instructables.com/id/How-to-get-better-results-from-your-UP-3D-printer/