Gas cylinders come in a variety of sizes and colors depending on their original use. In our case, we had a few left over from Blog Cabin 2015. A small white propane tank would make a wide, shallow hood, while a longer yellow oxygen and green carbon dioxide tank would make deeper globes typical of pendants.
Old tanks can be found at welding shops and metal scrap yards. If possible, have the valves removed prior to purchase. Flammable gases, oxygen and pressurized containers can be extremely dangerous. Be sure to fill each tank with water prior to cutting to ensure any old gases are completely displaced.
The easiest way to cut thicker walled tanks is by using a plasma cutter. A plasma cutter uses compressed air blown through a high voltage arc to create a plasma stream. It will also leave a unique edge to the metal cylinder.
Thinner walled tanks can be cut using an angle grinder and fiber disk. If you don't already have a plasma cutter, they can be rented from many tool supply houses. Because of the intense UV light and heat involved, regular welding gear is needed, so be sure to have a shielded mask and gloves available.
Test your amperage settings on similar thickness steel so you can get the cut speed dialed in without ruining your cylinder. Grind a section of steel bare before attaching the ground clamp to ensure metal-to-metal contact. For thicker tanks, you may need to increase the amperage while slowing your cut speed. Also, start by dipping the plasma tip into the steel at an angle so the molten portion blows away from you. Once the plasma has cut through the wall, angle the tip back perpendicular to the cylinder.
When using an angle grinder, it may be easier to follow an existing weld line to keep the cut perfectly straight around the tank. Be sure to go slow so the blade doesn't grab and jump the grinder out of the cut. Feel free to alternate between straight and angled cuts to meet the desired design style.
Because the gas cylinder weight may be too heavy for most pendant light kits, we used 5/32" stainless cable with cable clamps to support the weight. Feed the plug end of the light kit through a center hole in the top of the cylinder and tighten the cable clamp against the stainless cable. Set the desired height of the pendant by positioning the clamp higher or lower on the cable.