thought i had wandered into the wrong forum...
what is a good target temp and how much variation is allowable?
The acid is not needed, we stopped using it back in the 70's. Powder chalk and distilled water is key. You must clean the edges and bevel first, then rinse, then chalk the mirror. I have silvered hundreds of optics, from 4 inch to 36 inch for precision optical testing while at Tinsley. The mix must be fresh, temp control and very clean area and optics. The Oregon group have addressed these issues with data and great results. The AG chemicals work great, they are very happy with the results.