Sonostar is a California-based company dedicated to the worldwide sale and distribution of high-quality PVC hub connectors and DIY Dome Kits used for the building and repairing of PVC geodesic domes and structures.
Kits and connectors from Sonostar have been used around the world to erect a wide variety of practical, highly functional geodesic structures, including:
In urban or suburban areas, our geodesic hub connectors and dome kits can be used to build durable, lightweight protective swimming pool enclosures and covered outdoor eating areas. Other uses include observatories, aviaries, greenhouses, garages, pet enclosures, and barns.
Prefer art over architecture? Use our geodesic spheres to create decorative, spherical art that showcases your talent and leaves a lasting impression on your audience. The only limit to how you use our Geodesic dome kits and PVC dome hub connectors is your own creativity. Of course, we also remind you that common sense is required in terms of safety and function. While PVC is strong, it does have its limits, and you are responsible for the safety and liability of any structure you make.
Sonostar is based in the USA. All the parts are assembled and shipped from
Southern California. If you’re a do-it-yourselfer, all you need to order is the hubs. If you’re not, but you still want a dome and you know someone who can assemble it for you, then buy the full kit. It will have everything in it you need except for the cover and any stakes you need to secure it to the ground. In your dome kit, we also provide all of the nuts and bolts you need to assemble your dome. All you need to know is the size you want your dome to be (either radius or diameter). Our geodesic dome calculators accommodate for the extra width that the hubs take, so you can rely on the numbers and trust the geometry.
At the conceptual level, domes are mathematically inspired structures that contain space, and how you make that container can take a myriad of forms. The really cool thing about geodesic domes is their structural efficiency and the symmetry that is so satisfying to look at. We hope you enjoy building your dome, and we love seeing pictures of the finished products from everyone who uses our Geohubs.
It started out that I wanted to cover my swimming pool in the winter. I thought to myself, “Why not build a geodesic dome to keep the heat inside?” This question launched a research quest that spanned almost a year, looking at all manner of domes and learning that there is a huge body of knowledge available today to help non-engineers to build basic domes.
Throughout the research, I kept an eye open for connectors that would take advantage of using PVC pipe. PVC pipe is relatively lightweight, readily available almost everywhere, inexpensive, and incredibly strong. However, PVC connectors for building domes were not available anywhere I looked. A friend in the plastics business recommended that I make an injection mold. To make the mold, I needed to hire an engineer to work up the specifications into a 3D design.
We wanted the parts to be efficient, but also to be specifically useful for building domes. Since every dome ultimately needs a cover, we made the center of the hub solid, so that whatever cover was used could be screwed into the hub without compromising the strength of the hub. We also wanted the hubs to be usable in both large and small domes, so we initially opted for a 10-degree curvature that would make for a top and bottom side. In small domes, the flex of the PVC pipe would be sufficient to make up the difference. In large domes, the flex would work just the other way around. We chose to start with a hub that would fit 1/2" schedule 40 PVC - probably the most common plastic piping in the world.
The engineer was able to run the design through a stress-load test that showed us that our hub would withstand at least 100 LBS of angular force on each arm, which is more than enough for a dome where the stress is equally distributed throughout the entire skeleton.
Solid prototypes were produced, and after some corrections were made, we produced a production run of the 5-Star and 6-Star hubs. To make the 4-Star connectors, we used a band saw to slice off two arms of the 6 Star hubs.
Once we had the hubs in hand, there was nothing left to do but build a dome. It was decided that a 24’ diameter Frequency 4 dome would be a good project to start with. Using another website's calculator, We determined the six different sizes of struts needed to make the dome, remembering to subtract 2.28” from each length to account for the hub width. ½” schedule 40 PVC pipe can be ordered in 20’ lengths, so we ordered 50 pieces and set to work cutting. A Frequency 4 Dome takes 250 pieces of pipe + 65 6-Star hubs, 6 5-Star hubs, and 20 4-Star hubs. Cutting the pipe was the most time-consuming portion of the project. Using a pipe cutting tool is a huge time saver, and color-coding the cut pipes with colored electrical tape proved very practical.
Next, we found a big grassy area to start building, and we staged all of the parts where we could easily access them. Since we knew the Dome would be 12’ high, be made sure we had a ladder that could reach the top. Using PVC welding cement, the pieces quickly came together, and within a few hours, the dome was erected.
What to cover it with? Coincidentally, the military uses a 24’ freight parachute that I was able to buy online at a military surplus website for $50. It was a little tricky to position it in the wind, but once it was on, it was easy to tie down. As we built our PVC dome, we speculated that others might think that PVC is a good way to go, so we decided to build a website where others could find and purchase the hubs.
After a couple of years and so many domes sold all over the world, we made some changes to the molds. First, we made a 4-star mold for the base hubs that was stronger than the 6-Star hubs that had two legs cut off. It gave the dome a much more finished look. Second, we found that almost everyone preferred to connect the hubs to the struts with nuts and bolts, as opposed to glue and welding cement, so we positioned bolt holes in each arm and had them molded in.
After reviewing customer feedback, we decided that we should build hubs for bigger domes using larger diameter pipe. We experimented with some models using 3-D printing and found that we could make hubs that fit both 1" PVC pipe on the inside of the arms, and 1 1/2" PVC pipe that fit around the arms on the outside.
The tests for these showed a 5-fold increase in strength, and the opportunity to build much bolder designs. We called these new connectors 'Megahubs', because they were so much larger than the 1/2" hubs.
Our company today sells dome kits worldwide, and we are excited about creating more and more accessories for our domes that can be added on later.