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YOU CAN 3D PRINT MOLDS THAT TURN OLD CARDBOARD INTO HARD PARTS

Shred cardboard, blend it into pulp with a little rice paste, pack it into a 3D printed mold and squeeze it in a vice: out comes a rigid part made of paper.

by Aidan (XYZAidan)

FULL CAD BOM FIRMWARE DOCS

Workshop

Built with3D printing

difficulty
●●○○○
time
an evening per mold
license
CC BY-NC-SA 4.0
repo
repo FINISHED0 stars

WHAT YOU’LL NEED

Videos
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COMPAREE VERDICT

This is a materials process, not a gadget. Aidan blends waste paper or cardboard into a wet pulp with a water-soluble binder, packs it into a three-part 3D printed mold and compresses it in a vice. Most of the water squeezes out, and what dries is a dense part that he describes as extremely rigid, between plastic and a very light wood. It can be sanded and drilled, and he could not break his parts by hand. The catch is water: a few minutes of soaking made a part crumble, so this is for dry-use objects such as trays, dishes and desk organizers. It is also slow: the mold stays in the vice for about a day and the part needs a day or two more to dry, then longer outside the mold. Parts shrink as they dry by an amount that is hard to predict, and the print's layer lines show on the surface. The video has been watched about 2.4 million times, and the Instructables guide gives the binder ratios, paper masses and print settings you need to start.

GOOD TO KNOW

  • —Seven mold designs on Thingiverse: a 60 mm coaster, a 25 mm cube, triangulated and sinusoidal surfaces, a topographic map of Mt. San Antonio, a dish and a desk tray. Each has STL files, and the dish and tray also have Fusion 360 source files.
  • —The Instructables guide covers molds, print settings, paper, binder ratios, pulp, pressing, drying and finishing.
  • —There is no parts list to buy: a blender, a vice, a binder and waste paper. The 3D printer is only for the molds.
  • —Licence is CC BY-NC-SA 4.0, which does not allow commercial use.
  • —The YouTube video from December 2019 is narrated and has chapters for each step.
  • —Published 18 December 2019; no electronics, no firmware.

Parts to buy

3 items

From our check of the build. Exact quantities and part numbers are in the creator’s BOM.

  • Binder (rice paste, PVA glue or corn starch)Find
  • Cheesecloth to squeeze out waterFind
  • Couple of clampsFind

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Can I build this?

PrintOne or more of the seven molds from Thingiverse. Each has three parts (base, wall and pressing tool), except the coaster, which has two.
BuyUsually nothing new if you have a blender and a vice: waste paper or cardboard, a binder (rice paste, PVA glue or corn starch), a cheesecloth to squeeze out water, and a couple of clamps.
Tools3D printer, blender, vice, cheesecloth, clamps, a screwdriver to lift out the pressing tool, scissors or snips to trim the edges, and 60-grit sandpaper. A paper shredder helps but scissors work.
SkillsBeginner 3D printing. The skill is in the pulp: getting the water and binder right takes some trial and error.
TimePrint the mold first. Making and packing the pulp is quick, but the part stays in the vice for about a day and then needs a day or two more to dry, plus extra drying outside the mold.
Cost$ — filament for the molds, a binder from your kitchen or a bottle of PVA glue, and waste cardboard.
SafetyLow risk. Pulp that is too wet can squirt out of the mold under vice pressure, and printed molds can crack, so keep your face away while tightening.

Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.

Videos

Recycle Cardboard Into Anything With 3D Printing10:26

Narrated video from December 2019, about 2.4 million views. Mold design starts at 2:12, pulp at 3:27, the binder at 4:06, pressing at 5:22, drying at 6:27, strength at 7:31 and the water weakness at 8:14.

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Gallery

Start here

Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.

  1. 1.Download one of the seven mold designs from Thingiverse (Aidan recommends the 25 mm cube for a first attempt. The coaster has two parts; the others have three: base, wall and pressing tool.)
  2. 2.Print the mold parts strong (He printed all molds in PLA. His settings: 10 to 15 percent infill with 2 shells for the base and press tool, 15 to 20 percent infill with 3 shells for the wall.)
  3. 3.Make the pulp and the binder (Shred the paper, add rice paste (or PVA glue for an easier start) and only as much water as the blender needs. Then squeeze out water until the pulp feels like wet clay.)
  4. 4.Press, wait and dry (Fill the mold, tighten the vice as far as it goes and leave it for about a day. Then dry the part in the mold, push it out, let it dry fully and trim the edges with scissors.)

Resources

Documentation, files and community threads for this build — we link straight to the original sources and never rehost the creator’s files.

KNOWN ISSUES

  • The parts are not water-resistant. Soaking one for a few minutes made it crumble, so use them only for dry objects.
  • Pulp that is too wet molds poorly and can squeeze out of the mold, sometimes explosively. Squeeze it in a cheesecloth first until it feels like wet clay.
  • The molds take a lot of pressure. He increased shells and infill on the wall piece, and recommends rounded edges in your own designs because molds crack at sharp corners.
  • Drying is slow: about a day in the vice, about a day in the mold with the press tool removed, then more drying outside the mold. A fan or vent speeds it up.
  • Parts shrink sideways and grow slightly in the pressing direction as they dry, by an amount that depends on how densely they were packed. Pressing harder and adding more pulp reduces it.
  • The licence is CC BY-NC-SA 4.0, so you cannot use the molds commercially without the creator's permission.

How strong are the parts?

Aidan has not run measured strength tests. He writes that he cannot break any of his moldings by hand and that it took a number of hammer hits to badly damage the desk organizer. He describes the material as extremely rigid, somewhere between plastic and a very light wood.

What kind of paper works?

Almost any: cardboard, white paper, newspaper, food clamshells, formed packaging and egg cartons. Avoid glossy and coated paper. You can mix types and even blend failed moldings back in.

Why rice?

Rice paste is the binder that holds the fibres together. He tested three binders: PVA glue is the strongest and easiest for beginners but is a plastic, corn starch is the weakest, and rice paste is his favourite because it is strong and organic. You make it by simmering cooked white rice in water and mashing it smooth. His ratio is 30 g of paper to 2 tablespoons of rice paste.

Can I make the parts waterproof?

Not with a tested method yet. Soaking a part in water for a few minutes made it crumble. Aidan lists a non-plastic waterproof coating as an open problem he would like someone to solve.

How much paper do I need per part?

His average dry paper masses: tray 60 g, dish 40 g, wave surface 35 g, triangle surface 25 g, topographic map 25 g, coaster 10 g. The cube varies with height. Make a little more pulp than you think you need.

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Aidan (XYZAidan)

Aidan, who publishes as XYZAidan, posted this process on YouTube, Thingiverse and Instructables in December 2019. The idea came from an experiment by Will Haude of 3D Brooklyn, where Aidan later did an internship, and he worked on it on and off for about two years before sharing it.

Star the project on GitHub

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