How to 3D Print a Paper Mache Mold

Hello and welcome to my first instructable!

This is a relatively basic task, all you truly need is patience, and in the end you will have a pretty snazzy eco friendly recycled cardboard creation!

3D Printer
PLA Filament
Design Files
Paper
Old Blender
Spoon or stick
Dye (Optional)
Water
Elmers Glue
Clamps
Fan (Optional)

Select 3D files. There should be 3- one piece is the base, one is the wall, and one is the press. Then print!

Once your pieces have been printed, they need to be sanded a little. Most importantly you need to sand the “button” and “button hole” (those are the points where your pieces will click together. Other than those spots, cut and sand down any supports from during printing and any wonky knobs that are on the press because those will show up in the cardboard is not smoothed out.

Find some old paper that should’ve been recycled a long time ago and shred it up, the smaller the pieces the better. Any kind of paper works: newspaper, old notes, card board, colorful construction paper. Keep in mind that whatever color your paper is will be the color of your pulp and then your cardboard. Also, it’s better to shred more than you think you will need.

Find yourself a good old blender that you are willing to never use for food again. Now take your paper shreds and throw some in there with a little bit of water (start with about 2 tablespoons) and about 1/3 bottle of glue. Start blending. It’s going to take a while to get the right consistency, but it helps to take a spoon or stick to push the pulp back to the bottom of the blender to get a more consistent blend. As it blends add another 1/3 of the bottle of glue, and a little more water (if it needs it, don’t add too much!!). Once it is well blended it will still be pretty thick, it should have the consistency of oatmeal. Now, if you didn’t use colored paper but you want a little color, you can add dye or acrylic paint, but don’t add too much. A little goes a long way.

The pulp right now is too watery to effectively stick together, so you need to squeeze out some of the water. I used a mesh sheet, but you can use a cheese cloth or even an old tshirt.

Now is the fun part. Take your 3d printed mold pieces and pop together the base and walls. Take your juiced paper pulp and press some into the bottom, evenly covering it. The thickness that you layer it is up to you, tho the more you add the longer it will take to dry. This also means that you will have a thicker and stronger finished product, so it’s up to you. Once it’s in there, take the press piece and push it down as far as it will go. Water will likely come out the sides, that’s good, it means you’re squeezing out the excess water. At this point you can take the press out and add a little more pulp if you want, or you can leave it. Once you have all the pulp in it that you want, you’re going to clamp it closed, placing come on the connection between the base and walls and some on the whole thing. Now you get to wait a few days as it does the first drying stage.

Once it’s been a few days, you can go ahead and take the press out. It’ll probably be pretty tight in there, so you can use a screwdriver to gently pry it out, going around the sides as you do. It’s still going to be damp to touch, so now it’s going to spend a few more days drying. If you’re impatient you can stick it in front of a fan, but it’ll still take time.

Once the molded part is dry to touch, you can take the bottom off, which will also likely be damp. Gently take the bottom off the same way you got the press out. Don’t try to take it out of the walls, as the inside of it dries the paper will condense and it’ll become loose and much easier to pop out of the walls.

Once it is dry you can take it out of the walls and you have a completed piece of recycled cardboard! You can use it for whatever you want! Good job!