I don't know much about recoating optical lenses but if this guy is doing it in his kitchen that's seriously impressive. Either way though, the gatekeeping is weird.
Now that I've done this a couple times I thought I'd at least share a rough layout of my process –
after a long search for a replacement for the one I had stolen in 2019, I got a great deal on a damaged and modded HVX Xtreme last summer. I was able to de-coat and refinish the front element, then adapt it to my HPX171.
Here's a before pic of the lens with scuffed front element:
The trick to removing the optical coating, which i unfortunately did not document, is to soak the whole front element in apple cider vinegar overnight. This step dissolves the aluminum-based metal deposits which make up the coating, without any need for buffing.
Afterwards, you'll probably still see some light scratches that were hidden underneath the scuffs. Here's where the next steps come in–
my sketchy work setup – any cheap random orbital buffer, a new polishing pad, and a small amount of automotive chrome polish are all you need.
Duct tape the front element to a sturdy object like so. Sit down, hold the object between the knees, and buff lightly and evenly, not focusing too hard on any specific area.
Be sure to stop after a few even passes, and make sure you're not pushing down too hard or long anywhere, which can give the glass surface a rough, orange peel-like finish.
Here's the final product, more or less back to new, minus one grain of sand-sized chip and the missing coating. Note the missing screws, we'll get around to that later.
HVX200 rear assembly, minus the rubber-cemented 72mm adapter ring that was used to screw this onto an HPX prior
yeeted the original outer ring + cut and trimmed an HPX mounting ring from an old century bayo mount wide angle adapter:
aligned to the camera bayo mount, drilled some holes in the right places, test fit, and reassembled. Old screws for test fit only
finished product with all new hardware and washers from
Sifvert Skruv AB