Improving the DIY integrating sphere

[VintageTech79]

Decades ago I worked for a color spectrophotometer company. One of the services we offered on one particular model was IS refurbishment. The spheres were cast two piece aluminum and bolted together The casting exterior was a roughly cubical shape. We removed them from instruments and separated the halves. All the old barium was rinsed off and the primer layer inspected for excessive discoloration from aging/contaminates(some were in paint stores)/mechanical damage. After drying acceptable castings for refurb were coated with -wait for it-Kilz White Primer I forget how many layers. This made a surprisingly good substrate for the Kodak Barium Suspension we sprayed on with a Graco gravity fed spray gun. Both operations required holding the sphere halve at arms length and applying a fairly rapid curling(swiveling?) motion to it as one sprayed. Checks were done between primer layer application to check for runs which nixed the halve for subsequent barium application. After both halves dried the sphere was reassembled and checked on a reference machine for quick ballpark reflectivity test then sent on to the customer machine to begin calibration with the new electronics or existing electronics depending on the revision/job requirement. Dont know if any of this will help the diy endeavor but thought it might be of interest.