I've been looking into this material due to the really nice surface finish and clean look (actually purchased some already 😅)
However I recently came across a video by CNC kitchen where he raised some potential health concerns relating to the fibers specifically inside the filament. One of the commenters mentioned they couldn't wash the fibers off their skin, and another likened it to the "3d printing equivalent of asbestos"
I don't plan to print with it just yet due to needing a hardened nozzle, and spare extruder parts. However when I do, i'm feeling a little worried about how safe it is - mainly whether the final printed part is fine for occasional skin contact, or whether this material should ideally be left to just cosmetic parts.
P.S. image not mine, taken from here
For the record, chopped strand fiber in a fdm printer doesn’t significantly increase strength- especially along layer lines.
It might increase tensile strength of the load is parallel to the layers, but that’s about it. In every other direction, the fiber doesn’t cross layers, and delaminating is the primary failure mode.
The strands would be more like glass fiber than asbestos- you wouldn’t want it in your lungs, but then it shouldn’t really be airborne.
A better option might be graphite filled, which will still get you that look, and help lighten the part without losing strength. Still would not want to sand it without ppe, though.
I used it in a project 5 or 6 years ago, and my experience was basically this. It's strong in the direction of the layers but brittle between layers. Works great for some applications, but I'd definitely experiment with it before committing to use it on anything where the strength of the print matters because it's really only useful in two dimensions.