Two viewers under Tested’s Fuse 1 demo asked versions of the same thing. One wanted to know what happens to the unused powder you don’t recycle. Another asked about the environmental impact, worried about “nano plastics” that end up in the ocean if they get washed away. Both are fair, and SLS powder disposal is one of the things new shops get wrong.
How should SLS powder disposal work?
Treat it as regulated plastic waste, not trash. Formlabs’ powder care page says unsintered powder, fresh or used, must be disposed of under your local ordinances and environmental regulations for plastic waste, in powder-tight containers. Its spill guide is blunter: unsintered SLS powder is classified as a microplastic, hazardous to aquatic life, and must not go down drains or into household waste.
So the second viewer was right to worry about washing. Rinsing powder off parts or hands into a sink is exactly what Formlabs says not to do.
What counts as powder waste?
More than you’d think. Formlabs says vacuum bags and filters used on unsintered powder count as unsintered powder waste. It also says any powder the vacuum picks up is waste, even in a brand-new bag, because the bag’s synthetic fibers can contaminate it. Spilled powder that settles anywhere other than the Sift’s workspace goes in the waste bin too, since contaminated powder can cause print failures.
The Fuse Blast waste hopper falls under the same rule. Formlabs says to dispose of it under local regulations and not to reuse blast media from it.
What about sintered stuff?
That’s easier. Formlabs says cleaned parts and sintered powder can go out with household waste, though neither can be recycled. Broken powder cartridges and build chambers get emptied of powder first and then disposed of under local rules.
Where do the rules actually come from?
Your location and your powder supplier. Formlabs calls the safety data sheet the primary source for safety and handling, and the disposal rules themselves are set by your local ordinances. If you run more than one brand of powder, pull each SDS.
How do you set up the shop?
Put two lidded, labeled bins by the Sift: one for unsintered waste (vacuum bags, filters, spills) and one for sintered scrap. Then call your waste hauler once and ask how they want microplastic powder packed. Write their answer on the lid.
Related on the Solvi blog: SLS Powder Cleanup: How to Keep Dust Under Control; SLS Material Changeover: Is Switching Powders Worth It?; Depowdering SLS and MJF Parts: When Is Automation Worth It?.
Sources: YouTube: Formlabs Fuse 1 demo (Tested), viewer questions; Formlabs: Powder care, storage, and disposal; Formlabs: Cleaning after a powder spill; Formlabs: Emptying the Fuse Blast waste hopper.