A few days ago, we silvered an 8” diameter 43” FL mirror that had previously been aluminized, and applied the Angel Guard coating.
We did a Ronchi test and some Foucault-Couder knife edge tests before stripping the aluminum and after the silver was applied.
To my amazement, we found that the mirror’s figure was about the same in both cases. How that works, especially how the Angel Guard coating is laid down so even and smooth over the entire mirror, is beyond me. But it DOES work.
Prior figure (aluminized mirror), seen with Ronchi grating of 100 lines per inch: https://share.icloud.com/photos/0LyqGC35cx0QfWKcd08aI0vzw…
Final figure (silvered mirror), with same Ronchi grating:
This is a video of us washing off the Angel Guard coating.
Here is a video of the finished mirror after drying. Notice that the very edge of this mirror did not take the silver coating, but the area uncoated is probably on the order of one or two percent of the total area.