You could try toothpase for polish :-)
That handle is sooooo cool!
I hope the plain cap beads idea works out, that would mean we have a possible collar solution for 16mm mcpcb lights 
Yeah, sandpaper to strip the coating. I think it could be anodizing. it’s quite hard to remove. If it is ano, applying some degreaser to weaken it might be a good idea.
I ordered some polishing compound off ebay, the standard blue bar of aluminium finishing compound and a tub of Mother’s Mag and aluminium polish. That has some good reports from other BLF members so hopefully I can get a nice mirror finish on this surface.
Toothpaste for polish? That sounds interesting, I’ll give it a go. Thanks
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I saw that they offer solid brass bead caps. Maybe there’s a chance of finding some solid aluminium ones somewhere? Would be interesting
Nice. The balance looks spot on, lucky. Hope your RLT collar works out.
I also found these as possible candidates:
They are hemispherical cup for washers. A good buffing and polishing could make them shiny and more reflective.
Ooh yes those look very interesting, perfect shape. Available in all sorts of sizes. Very expensive though 
Linus i was saving this idea for down the road but never got the funds to do it yet:( but i was going to buy this
and if u search Google there is a place that sells Stainless steel disc or sheet and i was going to drill a center hole and use the block to make my shape ?????
went with stainless steel because its shiny to reflect the light better ?
Loving all these ideas, might be worth starting up another diy collar thread soon.
I’m not sure if stainless would actually result in a more efficient reflective surface. Mirror polished aluminium is pretty good but I don’t know much about this stuff in terms of actual values. I believe the usual reflectors use a layer of vacuum deposited aluminium to achieve the final coating.
Different reflector coating materials. are shown here, vacuum deposted aluminium is rated at about 90% reflectance. No idea how close you can get to that by simply polishing the bare metal though.
I found them here starting at $1.50 for the smallest. Made of iron though, I am not sure if this is good or bad.
Even more interesting, those look like they come in a male and female set. Wouldn’t that be perfect to press and form sheet aluminium/stainless or whatever into little spherical cups?
They even come threaded so making a little squeezer with a threaded bar and set of bolts seems rather easy?
The material that the dies are made of wouldn’t matter then .
I think I am going to order a couple today. I was thinking of sanding and polishing them to a mirror finish and using them directly but perhaps I can use a very thin aluminum or copper washer, heat it up and shape them as you suggested. Keep in mind that these are not an entire hemisphere, only part of a hemisphere so one would be missing the light that could have been reflected from the sides.
Well, if the hemisphere is incomplete, one would be missing almost all of the light, because it would be out of focus, not directed back to the die. One would have to figure out at what height to float the thing over the emitter (not to mention HOW to do it) in order to get the light focused back to the right point. Probably better to use it for a mold to press a thin sheet of metal into the right shape, if that is possible.
i was just checking shipping on those and its $15+ :(
Has anyone tried a small Christmas sphere as a Wavien collar? those things are super shinny on the inside…
How can you cut a Christmas ball in half without shattering it in a 1000 pieces?
The same way you cut a bottle I think, use a piece of string soak it in alcohol, tie it around the sphere, light it on fire, wait a few seconds then immerse it in ice cold water, the thermal shock will cut it in half… There is a video using this method on a bottle, I’ll see if I can find it.
Here it is
something like this ??>>> https://www.youtube.com/watch?v=oZAgHL9zpGM
Yes