Barbell Weight Moulds

Designed this multi-part mould to cast weights out of concrete. While weight accuracy is only around +/- 15% depending on your concrete and aggregates, the consistency between weights is about 2%.

I chose to fit 28mm bars to maximise compatibility, if you use 50mm olympic bars you'll need to adjust this (see attached source file).

Source file (FreeCAD) for the 2.5kg mould is included for customization. I used the FCInfo macro to determine weight for a given concrete density (I used a concrete density of about 2.2kg/l). Use the Spreadsheet to modify diameters and thicknesses, the parts should update automatically.

I've included a post-print video illustrating the casting process as well as mould assembly and disassembly :

Notes:

• If you're only casting one or two pairs of weights, draft settings of 0.3mm / 20% infill should be fine but more than that will need better internal support around the screw holes.
• The "Ring" parts, being a functional part of the final weight, are best printed at a high infill percentage (I went for 70% Gyroid