William R. Watt wrote:

Laser toner sounds interesting except for the graphite coating. I don't
know what graphite does to resins. Carbon fibre is sought after for
combining with resins, but graphite? Imagine trying to clean up after
sanding. Ugh.

My understanding is that toner is not coated. Toner is micro fine,
ground, black plastic that is melted and fused to the paper in the
printer/copier. It's only real use with epoxy is as a tint.

Graphite is sometimes used an a epoxy additive to produce a slippery,
abrasion resistant surface on hulls.