FAT32 works for both OSes, but has a 4GB size limit per file, so it isn't ideal. However there is a 4GB file size limit. You could use NTFS but you will have to install additional software on the Mac in order to read AND write to the volume. exFAT then is the best option.
The riser duct is a problematic zone due to: -build-ups, alkali infiltration and chemical attack to the steel anchors. Following the general rule, we suggest lining the duct with bricks in the round sections and with castables in the square sections.
Riser: An extra void in the mold that fills with molten material to compensate for shrinkage during solidification. Gating system: The network of connected channels that deliver the molten material to the mold cavities. Pouring cup or pouring basin: The part of the gating system that receives the molten material from the pouring vessel.