The Domes at Casa Grande

According to an Associated Press article dated 21 August 2009 (seen HERE), construction of the domes by Thermoshell started in 1982 and was to house the InnerConn Technology Inc. circuit board manufacturing plant.  Originally occupying 135 acres, only 10 of which were to be utilized for structures, InnerConn was going to produce "circuit boards used in all types of equipment ranging from quartz watches to large computers."  Due to loan default in 1983 the factory never opened.

The Domes at Casa Grande


Flying Saucer


Dome Construction

The buildings weird shapes are a product of the construction process.  Large balloons were inflated and supported internally by steel scaffolding.  Cement was poured over the balloons to make walls more than 3 inches thick.  The cement was then covered by 3 inches of polyurethane to insulate the structures from the Arizona heat.  Over that is another thin layer to protect the polyurethane from the elements.  Over the years the protective layer has been compromised leaving the polyurethane exposed which accounts for the orange mottled coloring.

Dome Cross Section


Dome Erosion


Long Exterior Wall


Dome Interior

Inside the buildings differ according to purpose.  For example, one has troughs in the floor, presumably used to carry cables and was probably going to be the main manufacturing facility.  Another building is just a large open space and may have been slated as a warehouse.  The "flying saucer" shaped building was to be the office and was actually used as such for a short time until the loan defaulted.  There are other foundations in the area where other building were to be erected, but never were.

Interior with cable troughs

Warehouse type interior

"Flying Saucer' interior

Current Status

The domes were abandoned, and owned by the bank, from 1983 until purchased in 2006 by Simplicity Communications Inc.  As of 2009 the 5-acre site is for sale, including the 4 domes with over 20,300 sq. ft.  Asking price; $750,000.

Dome with cement pad

Dome outline

Exterior of two long buildings


The area has been featured on many websites and is usually associated with UFOs, ghosts, and witchcraft.  However, while doing research, my favorite sites were the few using the old factory for modeling shoots. :)

Dome Front

Dome skylight

Dome interior 2


The now defunct electronics assembly plant known as "The Domes" is located on Thorton Road south of Interstate 8.

Flying saucer edge

Dome door

Side of dome