Let me say up front: Polishing is boring. There’s no real sound, no tactile feedback, and the work is slow going. Unlike grinding, you can put in many hours of work and not have any obvious result. As a result, motivation slides and work slows. Since my last update I’ve put in another 2 hours. Even so, in that time I’ve learned a bit more about the process. Firstly, to my disbelief, it seems I cut corners at the beginning of the process – I have a few facets on my lap that are not making good contact. I know this because, when viewed through the back of the mirror, they’re a distinctly milkier colour than the rest of the lap, suggesting that they’re not quite touching the glass and trapping a thin film of cerium slurry. I guess this means more pressing is in order. So rather than my usual procedure of packing mirror and tool separately, I’ve packed them together, mirror on top of the tool, and will work some more tomorrow night. That gives 24 hours of cold pressing with just the weight of the mirror. We’ll see what that does.
Meanwhile, the current state of the mirror is as follows: To a casual glance, the mirror appears polished with a nice transparent surface. Closer inspection reveals what looks like a faint grimy film on the surface, though, which is thinnest at the centre and gets worse towards the edges. This reveals that the polish is incomplete – a fully polished surface should be absolutely spotless. In fact, if I shine a thin beam of light onto it, the surface shouldn’t be illuminated at all.
So ya. Much more work.