Paper Pulp Pot Mould

Our School uses a lot of paper and cardboard each day and much of it wasn't being recycled. Coupled with planting out a new garden and seeing the masses of plant pots. I though I'd experiment with creating a form in the shape of a plant pot that could vacuum on recycled paper Pulp and then mould it into a useable and biodegradable pot.

3D Modelling - steps 1 - 3

• Fusion 360
• Computer
• Mouse

Mould Creation - steps 4 - 7

• 3D Printer
• Fine Mesh - metal flyscreen
• Fly screen tape
• 4 bolts + 4 nuts
• Drill
• Metal Plate - 2 to 4 mm is thick enough
• Metal tubing/pipe (what ever you have will probably work). This tutorial used 12-13mm tube scrap

Pot Forming - steps 11- 13

• Shop Vac - wet dry one
• Blender
• 3D Printed adaptor
• Bucket of pulp slurry
• Mould - male and female

The following instructions will step you through the process for creating both;

• male (the inside of the pot) and
• female (the outside of the pot)

This will utilise Fusion 360 and was the first attempt at modelling with the program.

1. Create a new sketch using 2 squares, being the distance apart that will become the height of the pot.
2. Sketch both squares on the same plane and then move the larger square up the desired height
3. Using those 2 squares, a solid structure can be formed by using the loft function. create → loft
4. On the underside of the pot, a square was sketched
5. The square was then extruded upwards to give the slight indent of the pot
6. All the edges of the pot (excluding the top) were selected and then the fillet function was used to create the rounded edges. modify → fillet
7. The model was selected and then shelled. Adjusting the wall thickness to ensure the model is strong enough but ensuring the walls are not too thick to ensure good water removal. modify → shell
8. A sketch was created with a large number of holes. To save time and sanity, use the pattern tool. For the main section this was created with the square patter and the edges were filled in with the circular pattern. create → pattern (then select either circular or square). Using the arrow keys to extend the area you wish to fill and increase the number of holes across the space.
9. The circles were then extruded in 2 directions to create holes in the two opposing walls
10. This process (7 & 8) is repeated on the other axis to create the required holes on the remaining two sides. This should bring you to image. Male 9
11. Created a new sketch and made a square on the top edge.
12. Select the outer ring and extrude up
13. Create 3 pegs (ensures the correct alignment when paired with the female mould

The overall summary of this step, is create another pot, seen in steps 1 to 5 (without the holes and slightly larger pot than the original) and subtract that from a solid cube. The steps are detailed below

1. Create a new sketch using 2 squares, ensuring you use the same dimensions of the previous pot, being the distance apart that will become the height of the pot.
2. Sketch both squares on the same plane and then move the larger square up the desired height
3. Using those 2 squares, a solid structure can be formed by using the loft function. create → loft
4. On the underside of the pot, a square was sketched
5. The square was then extruded upwards to give the slight indent of the pot
6. All the edges of the pot (excluding the top) were selected and then the fillet function was used to create the rounded edges. modify → fillet
7. Adding a square onto the top of the pot to create a top and extrude out to desired height, it doesn't matter as this pot isn't being printed
8. Once the pot is complete, select the whole pot and make a group. select all by dragging select → right click → make group.
9. Move the pot to sit inside the cube with the upper edge of the pot being flush with the cube as well as centering as much as possible
10. Combine the 2 shapes, subtracting the pot from the cube.
11. Modify → Combine.
12. In the menu
13. target body = cube
14. tool body = pot
15. operation = middle selection which is 'cut'
16. Move or delete the pot mould and this should leave you with a slightly larger pot shape. The difference between this model and the male will be your wall thickness of the pot mould + room for the mesh (seen in step 6)
17. Following the process outlined in steps 7 to 9 in the male mould instruction box, create holes penetrating the inner wall of the pot but not the exterior

1. Export the models as an STL, this takes some processing time from Fusion 360, Below is attached the female mould stl. The male file turned out to be 90mB which cannot fit on instructables pages.
2. Two screenshots show the orientation that the moulds were placed for printing, ensuring any scaffolding is on the non-pot surface.
3. The images shown, are for printing on a small flashforge printer (Adventurer 3)
4. The following images show what the pots look like post printing. You will notice, I ended up drilling out the tabs as they were too weak and will use those holes for the bolts later

The male part of the mould needs some adjustments to allow water to be drawn through as well as a surface for the paper pulp to 'matt' over.

Mesh

1. Using the flyscreen trim and mould it to take shape of the mould.
2. Using the fly screen tape, adhere the flyscreen into the pot shape
3. Loop the flyscreen over the top edge of the mould (the metal plate will clamp this into place later

Top Plate

1. Carefully measure out and cut a square piece of metal that is the same size as your mould (top)
2. File/sand around the edges to make them dull and reduce the chance of cuts or slices
3. Draw lines from each corner to its diagonal, where the intersections are will show where the central spot is.
4. Mark the intersection with a centre punch and drill, enlarging the hole to the same diameter of your metal tubing. Making the hole slightly smaller is preferred
5. If the hole is slightly smaller, widen until the pipe fits with some force. Then silicon

1. Using a blender, shred up the cardboard into a slurry
2. Dilute down the slurry, this means when the pot is submerged, it will draw the fibre on evenly

1. Attach the pot to the adapter and then to the shop vac
2. Turn on the shop vac and then submerge the pot mould into the slurry
3. Withdraw after a few seconds to check the coverage on the Male Mould
4. Resubmerge if required
5. Place and squeeze the two pot moulds together
6. Turn off the mould while the two parts are together
7. After 15 seconds (or so, it may vary between setup) separate the 2 moulds
8. Carefully remove the paper pot from the mould and place upside down on a surface to dry
9. Insert a plant and take a photo