Slice smooth, wet sand with 1000 grit, then 2000 grit, then 3000+ grit polishing compound. Really, the polishing probably isn't needed most of the time since the sliced dome is already pretty smooth, but it looks nice when it is super shiny. Obviously when you are doing 2000+ grit cleanliness is super important---any grit can leave much deeper scratches than that.
I don't like to use any chemicals when doing the dedomes; in the past it seemed to affect the phosphor somewhat giving some extra tint shift and unknown longterm longevity. I use only heat (traditional soft domes like XM-L2) or a sharp blade.
Absolutely love my D4 from Mountain. Got to love that tint on the Nichia’s. My first Nichia light, won’t be my last. Works flawlessly and got here quick. I carry it everywhere with me now. I plan on adding the rest of the lights to my ever growing collection. Thanks for all the hard work.
Thank you all for making this possible. I am going to have to defer a few weeks on the giveaway, but I've got it marked on my calendar and am going to have a few good items for the giveaway (and yes, some will have 4000K emitters). :-)