This project demonstrates the use of agar, a bioplastic sourced from seaweed, for the fabrication of small lampshades. Agar is a very popular bioplastic used among the biofabrication community and is available in most grocery stores in powder form as a vegan alternative to gelatin. Additionally, the project requires practically no specialized materials, relies on typical household kitchen equipment, and can be completed rapidly in 3 steps. This project offers a low-risk, low-cost, and hands-on way to introduce students to the concepts of bioplastics, biofabrication, and phase transition.

Supplies

Materials:

Agar powder
Water

Equipment:

Cup
Tap water
Kitchen scale
Small pot and stove
Rubber spatula
Kitchen thermometer
Non-stick aluminum foil
Existing plastic lampshade as mold
Metal spoon

Step 1: Dissolve Agar in Water

Weigh out the agar powder and water to dissolve the agar. The exact concentration is not critical. The lamps shown here were obtained from combining anywhere from 3.0 - 6.0 grams of agar powder with 200 grams of tap water (around 1.5% - 3.0% w/w concentrations) in a cup. In general, the final product will be sturdier with higher agar concentrations but will also be more opaque. Once the mixture has been weighed out, pour it into a small pot and heat the mixture on the stove until it begins to boil. Constantly stir using a rubber spatula during this process to ensure the agar is fully dissolved.

Step 2: Pouring the Agar Mixture

Once the agar boils, allow it to cool to approximately 45 degrees Celsius, while occasionally stirring. While waiting for the mixture to cool, take existing lampshades and cover them with non-stick aluminum foil in preparation for pouring. At 45 degrees Celsius, the mixture should be noticeably more viscous than water when stirred. At this point, it is optional to incorporate decorative additives directly into the mixture, such as a few drops of food dye. In this demonstration, dried flowers was used. Agar begins to solidify at and below 40 degrees Celsius approximately, depending on the brand and purity. If solidification occurs, simply heat up the mixture and wait for it to cool again before continuing. Using a metal spoon, transfer some of the mixture and pour it directly onto the inside surface of the existing lampshades (now covered with aluminum foil). The agar mixture should solidify into a gel relatively quickly upon contact with the foil. Repeat this process until all parts of the foil is covered. Repeat this step several times to ensure thorough and sufficient coating.

Step 3: Dry and Assemble

Take the agar-coated lampshades and place them near areas of ventilation, such as near a window. Wait for the agar gel to dehydrate. This may take several days. During this time, the agar gel will shrink and become thinner, and eventually delaminate from the non-stick foil. It may be necessary to manually peel off some portions of the agar. At this point, the agar lampshade is complete and can be attached to the existing lamp. The final lampshade product will take on the surface patterns of the foil. In other words, smoothed foil will produce smoother agar lampshades whereas wrinkled foil will produced wrinkled lampshades. This may produce additional interesting results when looking at their shadows. Agar is compostable. If the project is to be discarded, simply break apart the agar lampshade by hand and discard it into a composting bin.