barbell weight

Preferbly print this in ABS/PETG so you can keep them outdoor, Inflill and speed does not really matter, I printed with 100% infill and 0.3 nozzle height.

The only complicated part is the weight ratio of the material you use to fill them. I found quick-mix ruck-zuck beton and did couple of test to calculate the ratio and then sized the weight shell according to that. If you use heavier or lighter material you might need to resize the shell.

Some of my super complicated calculation when comes to density:
~water density = 1 g/cm3
~concrete density = 2.4 g/cm3
~cement density = 1.440 g/cm3
~sand density = 1.6 g/cm3
~stone density = 2.5 g/cm3
~Calculated German cement = 1.9 g/cm3

Note:
I printed 1KG, 2.5KG without any support and they printed fine, you will however need support for 5KG shell.
For 10KG, that is more complicated if you have small printer, you will need to split and then glue them back.
I did not have problem of leaking with cement as it was quickly ab