Materials
Processes
protective coating
The porthole got a protective coating because it served as a window in my client's bathroom, and there's no easy access to polish it. An unknown acid had etched the glass; thus, I ordered a new glass. Unfortunately, like everything nowadays, finding a glass shop that still has plate glass and will do odd jobs is getting more challenging. Plate glass is different from laminated or tempered. Its thickness is critical to the proper fit of gaskets within the porthole.