i would like to share my new diy reflector, which was made under 1$
not sure if it’s a win or lose, but IT’S FUN
what’s my plan?, i gonna make a bigger one, then use it with 100w cheap china led 
btw, does anyone know if there is silver paint that i can spray on and resistant to heat, alumium foil is not a good idea
hmm, my image is not appeared, so here’s the link
https://imgur.com/a/UECMg
Here are your pictures, mrheosuper:
Remembers me months ago when I bought a small E14 incandescent reflector bulb. It was too small for its lampholder, so I fixed it by attaching triangle shaped strips of aluminium foil to its back plate, which upon bulb installation I carefully glued to the lampholder rim for improved light extraction. :-D
Cheers ^:)
Try to use mylar or chip package aluminized film. May improve the performance? :laughing:
i have ordered some flexible mirror, and going to make a bigger version
it gonna cost more, but not like over 50$ for 10cm reflector
How are glass shops making mirrors?
They surely add a layer of relfective material to a flat piece of glass.
I’m sure it’s not some high-tech process.
The question is: can it be applied to wood?
If yes, we could make cheap and OK wavien collars.
Mellon ballers have very low reflectivity, it should be possible to double it easily making up for lower precision.
Thanks for the vid Enderman
this is exactly what i’ve been looking for
I cut a reflector out on my lathe one time. I didn’t do any kind of studying up on reflectors before I started. Just didn’t find a reflector any where that was the size I need(Custom built light). I thought it be fun, since I liked making chips on the lathe anyway. I made a reflector, at least that’s what it looked like. Polished the aluminum to a high shine. Stuck it in the light and wow, what a crappie beam. The beam profile was all over the place and no where was it really uniform. I started reading up on how to make a reflector that accounted for all the light angles. I soon realized it was way over my head, and I just leave that part to the professionals now. I can still take a slightly larger reflector than what I need and cut it down to fit much easier. Way better beam profile than I can do by far . :person_facepalming:
Pretty cool idea you got there and probably fun to. 
It needs to be a perfect parabola.
Unless you have a cnc lathe, this is pretty much impossible to do by hand.
Even with a CNC, if you want decent quality you need to diamond turn it, not with a regular cutter.
Otherwise the tip of the tool will have a radius which also needs to be accounted for when shaping a parabola such that the surface is at the correct angle to the focal point.
Mine was far from perfect.
I never realized there was so much that went into figuring out a reflector that works with a particular light source until I read up on it. I remember seeing some software somewhere that could do it for I think but still there was no way I could follow the curve needed on a manual lathe.
It’s just a parabola.
The only thing that changes is the focal length, aka size.
But yeah you can’t do it by hand.
Mmmkay, bear with my ignorance but as far as I understand “a certain reflector shape” = a “certain beam profile”. Pretty sure, for example, we could get a reflector tailored for perfect coupling to a given aspheric lens… expensive custom build maybe?
What beam profiles would be attained with other easily attainable shapes like a cone or cylinder? I'd love to have a perfectly shiny sliding surface tube for zoomies, no jokes! :-D
Cheers ^:)
The reflector “tailored for perfect coupling to a given aspheric lens” is called a wavien collar.
any other design of reflector will not be useful for throw because the lens only collimates light coming from the focal point.
The only way to have a reflector add light to the focal point is by having a downward facing spherical surface focused at the LED.
Any other reflector and it will just add spill around a hotspot, usually very ugly looking too.
