That was my first thought too but apparently it's ceramic 3D printing (the only ceramic printers I've seen are like $MM). I wonder how that can possibly scale to be as cheap as what mossy earth is doing by epoxying sand onto a metal frame and metal twist tying coral fragments onto it.

[–] plinky@hexbear.net 22 points 4 weeks ago* (last edited 4 weeks ago) (2 children)

there are burn filaments for ceramic (and metal) i believe, so they are porous, but pure ceramic after burnout (they have like 30% plastic/70% ceramic, plastic is burnt out at like 700c or something and leaves ceramic/metal part*), and can be printed with cheap 3d printers

*with lots of holes in it, so not structurally sound, but here it's not important and probably even desirable.

[–] BakedCatboy@lemmy.ml 14 points 4 weeks ago (1 children)

Yep that's correct, with ceramic you don't end up with any plastic in the final product. I'm more familiar with SLA ceramic printers which use a resin, and FDM metal printing that uses a kind of wax, also burned out in a tube furnace.

[–] plinky@hexbear.net 12 points 4 weeks ago* (last edited 4 weeks ago) (1 children)

I more meant that ceramic 3d printing is not automatically $mm, at least after journalism word converter, it can mean just ceramic fdm mass-friendly approach.

although from 2019 i found they (maybe different they?) used something like cornstarch filament, even friendlier i assume (https://www.udel.edu/udaily/2019/october/3D-printed-coral-study-damselfish-Danielle-Dixson/)

[–] BakedCatboy@lemmy.ml 13 points 4 weeks ago

Gotcha, yeah unfortunately FDM ceramic still has crazy high spool costs so I don't think it really puts it into the same ballpark as using simpler materials. We're talking like $500 a spool, just one printed piece like you see in the picture looks like it would take an entire spool or more and could be the better part of $1K. I'm comparing to Mossy Earth's strategy of binding together metal rods and coating with sand, which after labor lands at $26 per structure.

[–] ArmoredThirteen@lemmy.zip 11 points 3 weeks ago

Having lots of holes is a crucial part of reef structures. It provides surface area for more things to live in