To repair a broken plasma ball, also known as a plasma globe or light, nebula spheres or lightning balls, requires an understanding of how they work. In brief, electricity is used to heat pressurized and ionized gases. The heated gases create a colorful light show and a static charge. When the globe is cracked, the gases escape, and there goes the light show. Though most store-bought plasma balls are inexpensive to replace, you can replace the globe and gases and reuse the electronics.
Remove the broken globe. Make sure the base area is smooth. Sand if necessary.
Install the aquarium tubing through the base. The tubing is your means of evacuating the globe and introducing the gas.
Epoxy the new globe in place. Let dry thoroughly or risk globe damage when you vacuum out all the air.
Attach the tubing to the vacuum pump. Remove the air in the globe.
Replace the air with your chosen gas or gas mix. The type of gas or gases you use determine the colors and patterns the plasma ball makes. Begin with a small amount of gas. If you don't see the finished results you are after, you can always add more gas. If you want a blue or purple display, use helium or nitrogen. Neon gives off red or orange colors. Xenon provides gray or lavender light. Krypton can display a variety of colors, depending on the amount of pressure it is under.
Make sure your globe is clean. Impurities can affect your results.
If you have difficulty locating a globe, you can use the existing electronics with a clear light bulb to create a plasma light show.
Avoid changing the voltage. The globe may explode if the gases are in contact with high voltages.