Abstract
Background
The newest project site for the Practivistas Dominicana program is in Arroyo Norte. Arroyo Norte is a community, which was built in close proximity to Duquesa, the dumpsite for Santo Domingo. The dumpsite is the largest in the country, and the community exemplifies Appropriate Technology by building homes, community centers, and markets out of the materials they have in abundance at the nearby dumpsite. They have asked for us to come in and use the waste materials to build prototypes with them for furniture and walls to construct a new supermercado in Arroyo Norte. This would be the first large market in the community. The market will be built in the near future, but for this project we will only be experimenting with materials to develop alternative designs for things necessary in a marketplace. The 25-room supermercado will need a funding source, which we hope our prototypes will help generate upon completion. Our role in this project is to develop aesthetically pleasing, structurally sound, and economically feasible prototypes for use in the supermercado.
Problem Statement
The objective of this project is to research and develop wall and table prototypes that can be reproduced and used in a sustainably constructed market in Arroyo Norte, Dominican Republic.
Criteria
The following table of criteria was developed in a community meeting and is used to evaluate alternative solutions.
| Criteria | Constraints | Weights |
|---|---|---|
| Resistance | Prototypes must successfully pass the spray test, scratch test, and tensile strength test. | 10 |
| Marketability | The prototypes must have potential for reproduction at minimum, and potential for revenue production at best. | 9 |
| Aesthetics | The prototypes must at least be visually acceptable to the community members involved, and at best look "clean". | 9 |
| Security | The wall prototypes must look secure and be resistant to break-ins. | 9 |
| Educational Value | The prototypes must display reused materials in some way. | 9 |
| Accessibility of Materials | At least 90% of materials used in the prototypes must come from the Arroyo Norte waste station. | 9 |
| Mobility | The furniture must be movable by 2 or less people. | 8 |
| Adaptability | The prototypes shall be created with room adaptability in mind. | 7 |
| Cost | The prototypes should minimize cost where possible. The walls shall not exceed $100 USD each, and the tables shall not exceed $50 USD each. | 6 |
Literature Review
See our Literature Review for relevant research completed for this project.
Construction
Timeline
The table below outlines a timeline for Team Terrific to complete the prototypes by Thursday July 3, 2014.
| Date | Activity |
|---|---|
| Monday, June 16 | Complete Budget/Finish negotiations with practivistas |
| Tuesday, June 17 | Brainstorm Explosion/Plastic Bottle cap Mold Extravaganza |
| Wednesday, June 18 | Complete plastic research/Brainstorm Explosion #2 |
| Thursday, June 19 | Work day - Melt massive amounts of HDPE Plastic #2/Finalize caps & bottles |
| Friday, June 20 | Purchase plastic tools to mass produce plastic tiles |
| Saturday, June 21 | Finish all plastic prototypes/Finish wood chips and resin |
| Sunday, June 22 | BEACH DAY |
| Sunday, June 29 | Build on and perfect prototypes/Beauty with Mama |
| Monday, June 30 | Work on presentations |
| Thursday, July 3 | Present Projects |
Costs
The table below describes the cost to replicate our completed prototype projects. The cost table below does not include experimental materials and tools. Costs are listed in Dominican Pesos.
| Quantity | Material | Source | Project | Cost ($)DOP | Total ($)DOP |
|---|---|---|---|---|---|
| 3 | "Calentador"/Sterno cans | La Sirena | Plastic Wire | 48.41 | 145.23 |
| 1 Quart | Waterproof wood paint | Centro Ferreteria J&R | Cable spool table | 750.00 | 750.00 |
| 1 | Paintbrush (small) | Centro Ferreteria J&R | Cable spool table | 250.00 | 250.00 |
| 5 | Sandpaper (60 and 220 grit) | JV Ferreteria Cerrajeria S.R.L. | Cable spool table | 37.17 | 185.87 |
| 2 | Wood palettes | Duquesa | Earthship Bar | 150.00 | 300.00 |
| 1 bin | Plastic #2 HDPE | Duquesa | Plastic Prototypes | 200.00 | 200.00 |
| 1 gallon | Soy Cooking Oil | La Cadena | Plastic Prototypes | 418.00 | 418.00 |
| 2 | 12" Clamp | La Sirena | Plastic Prototypes | 392.00 | 784.00 |
| 1 | Transportation of duquesa materials | Duquesa | Plastic Prototypes | 500.00 | 500.00 |
| 2 | Floral snippers | Ferreteria U&P | Plastic Prototypes | 350.00 | 700.00 |
| 2 | 4" clamps | Ferreteria U&P | Plastic Prototypes | 275.00 | 550.00 |
| 3 | Scissors | La Sirena | Plastic Prototypes | 100.00 | 300.00 |
| 1 | Propane-powered grill | Mexico/Duarte Blender Repair Shop | Plastic Prototypes | 1,800 | 1,800 |
| 1 | Box cutter | La Sirena | Plastic Bottle Ripper | 63.33 | 63.33 |
| Total Cost | $6,946.43 | ||||
Completed Prototypes
This section illustrates a step-by-step tutorial on how to replicate the prototypes we created for the Arroyo Norte sustainable market.
Glass Bottle Wall
Materials needed:
- 100 Jumbo Presidente bottles
- earthen mortar: clay, sand, water
- shovel
- bucket
- level
- rebar
- eco-blocks
- gravel
- plastering trowel
- earthen plaster: cal putty, sawdust, sifter/ sifted sand, water
Plastic #2 Tiles: Melting In a Sandwich Press
These tiles were melted using a sandwich grill to melt HDPE Plastic #2, which was taken from the waste stream in Arroyo Norte.
Experimental Outcomes
The following documents explain experimental outcomes of our experiences melting HDPE plastic using an electric and a propane-powered sandwich press.
Electric Sandwich Grill
The following experiments document our experiences melting small pieces of HDPE #2 plastic into tiles using an electric sandwich grill and wax paper.
| Image | Experiment | Description |
|---|---|---|
|
Experiment #1 | We placed plastic in wax paper, put it in the sandwich grill, then turned the grill onto high heat. It took 15 minutes for the temperature to melt the plastic. This experiment was conducted in a home in Arroyo Norte using electricity that might not have the same voltage as the electricity outlets in the city. The wax paper stuck to the plastic material after it was completely cooled, which led us to believe that we used a poor quality paper, or the wrong type of baking paper. |
|
Experiment #2 | This experiment was conducted in the city with consistent electricity, on the same sandwich grill, and the same wax paper. The difference with this was that we got the sandwich grill up to temperature before placing the plastic inside. We also started at a medium temperature and increased it when we noticed that nothing had melted after 10 minutes. This sample of melted plastic was placed under 6 thin terra cotta tiles to cool with not much pressure, which caused many wrinkles in the final product due to plastic shrinkage upon cooling. |
|
Experiment #3 | This experiment was conducted in Arroyo Norte in the same sandwich grill and wax paper. This plastic was placed in the sandwich grill after it was already brought up to heat from a previous experiment. We started it on medium, and after 5 minutes, raised the grill to high temperature. It melted in 5 additional minutes, then we took the paper and plastic out of the grill with gloves. To cool, we placed the melted plastic between two sturdy pieces of wood, which were clamped together using 2 clamps holding over 5 psi of pressure. This is the most successful experiment by far. After it was fully cooled, we cut it into a tile shape using a hand saw. |
|
Re-use HDPE Scraps | Use pruning shears to cut the unused melted plastic material. This plastic can be re-melted over and over again using the same process. |
Propane Grill
The following experiments were performed using a large 12" x 12" flat paneled sandwich grill powered by propane.
| Image | Experiment | Description |
|---|---|---|
|
Experiment #1 | We turned the grill onto the lowest heat possible, it took 10 minutes for the grill to reach 325 degrees F. Once the temperature was achieved, we placed plastic confetti in wax paper, put it in the sandwich grill, and covered it with the same piece of wax paper like a quesadilla. This experiment was conducted in Arroyo Norte, outdoors. |
|
Experiment #1 Results | Successful! The wax paper stuck to the plastic material after it was completely cooled, but can be scraped off the cooled piece. This paper is not ideal, but it works for now. The tile looks smooth, and is about 1/4" thick. |
|
Experiment #2 | We started with the grill preheated to 325 degrees F, and used banana leaf instead of wax paper. The banana leaf was cut into large squares, and used just as the wax paper in previous experiments. Once melted into a tacky substance, it was removed from the grill and placed in a wooden press to cool. |
|
Experiment #2 Results | The banana leaf successfully held the plastic together without leaking onto the grill, which was successful. However, due to the moisture content of the banana leaf, the final product of plastic tile has visible bubbles below the surface, which aesthetically is not what we want. |
Plastic #2 Molds: Melting in cooking oil
CAUTION: Melted plastic is extremely hot, and takes hours to cool. Wear safety gloves and wooden tools when working with melted plastic and eye protection around hot cooking oil.
Earthship Bar
| Earthship Bar Prototype | Description |
|---|---|
|
This bar was created using old tires found in Arroyo Norte, filled with clay and dirt on site, and supported with rebar. The tires are bonded with moist earth (mostly clay), which is packed in and around the tires. Rebar was used to provide further structural integrity. Once the filled tires are leveled and the earth dried they will be covered in a plaster mixture of lime, sawdust, and a concrete mixture containing extra fine sand.
|
Materials needed:
- shovel
- used tires
- metal malette
- salvaged rebar/ pvc pipe
- earth (can be any mixture of dirt, sand, clay, etc.)
- level
- earthen plaster: lime, cement, sifter/ sifted sand, water, sawdust
- plastering trowel
- palette wood
- table top: gesso, portland cement, water, cabulla fiber, scrap rebar/metal sticks, scrap billboard material
Plastic Bottle Ripper
| Plastic Bottle Ripper | Description |
|---|---|
|
The Plastic Bottle Ripper turns large plastic bottles into long spools of plastic string of uniform width. The design utilizes a 90 degree aluminum angle iron, a razor blade, and a few nuts bolts and washers. To create this Plastic Bottle Ripper, take your angle iron, and cut 3 holes into it at various lengths to create various widths of plastic string. Next, drill 2 holes into the angle iron where the bolts will be attached. Then, place the razor blade near the holes and add the nuts, washers, and bolts to secure the blade (sharp side facing the corner of the angle iron). Lastly, secure the angle iron vertically, put a 2 liter bottle on the long bolt, feed a small piece of soda bottle through the hole, and pull the string. |
Maintenance
Schedule
Instructions
Conclusion
Testing Results
Glass Bottle Wall
- When the earthen mortar mixture is cracking, add more sand. When the earthen mortar is crumbling, add more clay.
- The earthen mortar mixture should be on the dryer side when applying.
Melting HDPE Plastic #2 in Electric sandwich grill
- Successfully melted thin plastic pancakes
- Plastic pancakes need to be folded while hot and repressed to create clean edges, or have edges cut off after cooled.
- Cook time: ~10 minutes
Melting HDPE #2 Plastic in Large Propane-powered sandwich grill
- Successfully melted thicker, larger plastic pancakes
- Plastic pancakes need additional work to create clean edges
- Cook time: ~15 minutes
Melting HDPE #2 Plastic in Parchment Paper VS Banana Leaf
- Parchment paper: Best material for melting plastic in sandwich grills because it does not stick, burn, or leave any impurities behind in the end result.
- Banana Leaf: Successfully melted large plastic pancakes with banana leaf. However, the banana leaf stuck to some parts of the plastic surface (~10%), which takes additional work to remove once cooled.
- Wax paper: Successfully melted one 1 out of 10 attempted thin plastic tiles with wax paper, but it melts, burns, and sticks to the plastic tiles most of the time. We were able to make it work at a very consistent temperature in the electric sandwich grill, but it's not ideal.
Melting HDPE #2 Plastic in Soy Oil on the Stovetop
- Melting in oil kept a consistent temperature, but left the pressed block very oily after it was cooled.
- Plastic pieces that were cut small heated to temperature quicker than re-used previously melted blocks of plastic.
- Cooking time: 15 minutes once oil is up to temperature
- This method seems to have the most potential for reproduction of melted plastic materials because it is efficient, quick, and easy.
- In Arroyo Norte: It would be possible to cook plastic with a propane-powered stove, but I would not suggest this method over an open-fire because it's important to keep a consistent temperature.
Molding HDPE #2 Plastic Bricks
- Successfully molded 2 solid bricks of plastic using a small wooden mold with a removable top, and clamps to keep pressure on the plastic while it cooled.
- Pressure was not enough with 2 clamps, so it had some bumpy edges. More pressure on the cooling brick would make cleaner-looking bricks that don't need to be cut smooth once cooled.
Molding HDPE #2 Plastic Blocks
- Successfully molded 3 large blocks of plastic using a large wooden mold with a removable top.
- The removable top fell into the mold, allowing any amount of plastic to be pressured evenly inside it
- This method can be very efficient for making plastic tiles, all you have to do is get the cooled block on a band saw and cut 20 tiles out of one block of plastic.
- This method has a lot of potential for the next steps of developing furniture for the Arroyo Norte marketplace.
Discussion
Lessons Learned
Next Steps
Glass Bottle Wall
- Plaster over the earthen mortar once the wall is completely dry.
- Mosquito-proof the completed wall. For example: Fill bottles with water and wine corks to seal the moisture and to illuminate the space more.
HDPE Plastic Prototypes
- Energy analysis of melting plastic in oil on the stovetop vs. propane sandwich press vs. electric sandwich press
- Find the most efficient way for community members in Arroyo Norte to melt large amounts of plastic safely (temperature cannot exceed 350 degrees F)
- Make a tall mold out of wood or metal to make table legs out of HDPE molded plastic. Mold must withstand the pressure placed on the cooling plastic.
- Experiment with the pressure used on plastic while it's cooling: does the small surface area really decrease the need for higher pressure (psi) if it's as tall as a table leg?
- Find a way to use reclaimed/repurposed materials from the waste stream for the molds
Troubleshooting
Team
Brought to you by Team Terrific, Practivistas 2014
