Building a Dome with Predrilled Sonostar Hubs, Nuts, and Bolts




predrilled hub with bolt and nut topside view

Building a Sonostar Geodome with Nuts and Bolts

The original concept for the Sonostar hubs was to take advantage of the superior strength of PVC and its lightweight density to build sturdy domes quickly and safely. PVC is permanently joined using welding primer and glue/cement. However, if you plan to disassemble your dome and rebuild it later, that doesn’t work. Using nuts and bolts (we suggest stainless steel since it doesn’t rust) is a viable alternative. Here are a few tips on how to put your dome together with nuts and bolts. If you’ve bought a full-dome kit, you’ll notice the struts are not pre-drilled. You’ll need to drill through the hubs with the struts in them to make a passage for the bolts.

• Make sure you have enough nuts and bolts before you start

• Do them as you go – don’t put the dome together and then come back and add the nuts and bolts

• Unless you’ve got a good reason to do otherwise, put the bolt in from the top side and screw on the nut on the bottom side. This way your cover won’t tear when you spread it over the dome.

• Use a rubber mallet to pound the strut all the way into the hub.

• Take an electric drill (cordless is best) and use the hub holes as guides to drill through the fully inserted strut.

• Drilling twice for each hole (once on each side of the hub) will make sure you don’t come out the other side in the wrong place.

• After inserting the bolt, tighten the nut with a nut driver (again, I think cordless electric is the best way to go).

• If you have a team of helpers, give everyone just one job, and it will go better that way; ie. one person uses the mallet to pound in the strut, one person drills, one person does the nuts & bolts.

• If you’re going to paint the structure (highly recommended because the UV can make PVC brittle after a couple of years), be sure to mark your struts in such a way that you’ll be able to know what color code each one was originally. Otherwise, you’ll need to remeasure and recode each strut before you reassemble your dome.

• Enjoy your project!

                            Predrilled 1/2" Sonostar 6-arm geohub