Ferrofluid Lava Lamp

Created and Authored by Jeff Huang, Edited by Jeffery Zang

Lava lamps have been around for decades, and they're still just as cool as ever. Not only do they look cool, but they also provide a calming atmosphere and a unique visual experience. The mesmerizing, ever-changing swirls of colorful liquid can be quite captivating, and the soft, warm glow of the lamp adds to the vibe of any room. With their unique look and hypnotic movements, lava lamps have become a staple in many households and are sure to add a touch of cool style and charm to any space.

Inspired by Ms. Berbawy's Principles of Engineering class and Veritasium, I decided to take the phenomenon of the lava lamp to another level with a ferrofluid lava lamp. A ferrofluid lava lamp takes the coolness up a notch with its mesmerizing display of magnetic liquid and its ability to create shapes and patterns, which can be used to create a soothing atmosphere, stimulate the mind, and even create a focal point in a room. The ferrofluid lava lamp is sure to captivate any onlooker.

I was inspired by other lava lamps on Instructables and this product listed on Amazon.

3D Printer - Prusa Mini & Prusa MK3S+

Glass bottle

Ferrofluid

Distilled Water

Table Salt (NaCl)

A15 Incandescent light bulb

Light bulb socket

Button

Lamp cord

The first step of creating the lava lamp is creating the top part of the lava lamp.

I opened Fusion 360 on our computer and created a new design. To start the design, I clicked the "Create Sketch" button which draws an image that I can then use to create what we want. Then we used the sketch feature to draw the shape of the lid that we measured earlier. Since it is a lava lamp, I decided to make it in the shape of a rocket. It is very important that we made sure to dimension the lid correctly or else it would not fit on the bottle. Once dimensioned, I used the revolve command to generate a 3D model around the y-axis. I also changed the thickness of the lid so that it was a good shape for our design. Then I used the modify command to add fillets and chamfers so that it would be smooth around the edges. Finally, I exported the 3D model as an STL file and sent it to a 3D printer to create a physical model of the top part of the lava lamp.

If your bottle has the same or similar dimensions to the one we have, you can use my Fusion360 file.

These Fusion 360 tutorials were very helpful :)

I made sure to save the design regularly during the process and made sure to double-check the dimensions before printing.

First, I prepared our Prusa Mini 3D printer by setting it up and making sure it was calibrated. Then, I took the 3mf file from Fusion 360 of the Upper lid. I adjusted the settings in the slicer software so that it would print correctly. I changed the layout of the slicer software so that I could ensure that there were no faulty gaps or overhangs that would cause the printer to break.

Once finished with this step, I reviewed the file and settings and then saved the model as an STL file and transferred it to the printer's Sd card. Then, I selected the color of the print, in our case purple, and loaded the filament into the printer. I then started the print and monitored the start of the print to make sure the printer was printing correctly. After completion, I removed the print from the build plate. I tested the print on the upper lid of the bottle and made sure it fit snuggly.

If it didn't fit correctly, I would measure the lid again and try printing it again following the same instruction. I did this until it fit.

CADing the Lower Base is a harder part of the project. I tried to imitate a normal lava lamp with this step. In the base of the lava lamp, I used an incandescent light bulb, similar to what is typically used in a conventional lava lamp. In addition to just providing light, it provides heating to the bottle, allowing for the ferrofluid to circulate in the bottle. The denser ferrofluid would heat up and since hot fluids are less dense, the ferrofluid will rise to the top of the bottle. After some time the ferrofluid will cool and fall back down to the bottom.

I needed to CAD the base around the bottle so that the glass bottle can sit on the base and we made sure to also have room for the light to shine through in. It is very important to ensure the stability of this part of the base, while at the same time fulfilling these requirements.

I also CADed two smaller holes on the side of the base. The first one is where a button will go, which will complete the circuit once the lava lamp is fully completed. The second one is where the extension cord will leave from, allowing me to connect the cord to the wall outlet.

I also CADed a lid for the base so that I can take out the light bulb whenever I need to. I made sure to dimension the lid so it will fit snugly on the base, while not being so tight that it gets stuck.

I used a Prusa Mini or any 3D printer to print out the base. To save filament, I test printed certain connections and parts before fully printing the base. I then exported the CAD files into Prusaslicer. From there, I made adjustments for printing and exported the file to a Prusa Mini.

I placed a button into the corresponding button hole in the base.

I soldered the button to the lamp cord and incandescent bulb. Cut the wires so they are the proper length for soldering. I made sure the solders were neat and used heat shrink to prevent possible short circuits.

I then placed all the wiring except the lamp cord inside the base, and closed the lid, with the lamp cord coming through the corresponding cord hole. Make sure the light bulb stays standing.

After designing parts for the bottle I prepared the actual bottle.

Ferrofluid is very messy and can easily stain and ruin bottles if precautions aren't taken. The one solution we found was simply filling the bottle with water saturated in salt. Although the chemistry is not totally clear, this prevents the ferrofluid from any staining, most likely because the salt causes the water to be extra polar and does something similar with the glass, making the interactions between them and the oil-like ferrofluid less favorable.

This step is the most important to ensuring your lava lamp looks cool and lasts, as ferrofluid is somewhat unstable and can interact with everything in the bottle.

Add the ferrofluid to the saltwater solution dropwise through a pipette. Make sure the pipette tip is submerged under the water to prevent the ferrofluid oil from leaving and forming on the top of the water. Add as much as desired, however too much ferrofluid or too little ferrofluid may not look particularly aesthetically pleasing.

Close the lid to the bottle and attach the 3D printed parts. If a part is slightly too tight, feel free to sand down the part. If there are still issues, redimension the parts on Fusion360 and print a new part.

Enjoy your own 3D printed ferrofluid lava lamp!