Don't settle for tape or sputtering paint!

[bfg9000]

Don\'t settle for tape or sputtering paint!

Hi everyone, this is my first post here!

If you just want a smoother beam, why coat the reflector or lens with light absorbing materials like WriteRight or Krylon acrylic paint? Just frost the bulb like how reflectalite.com does it--or frost the glass LENS.

Go to any crafts store, and get a glass etching kit with hydrofluoric acid in it (important, because some come with clear paint like the Krylon sputter mod). I got 3oz of "Armour glass etching cream" for $7. Dip the bulb in and let it sit for 5 minutes before washing it off and it's frosted. The etching scatters light but doesn't absorb it like a coating, and if you have a Mag85 or HID you don't have the option to use those anyway.

HF acid is nasty stuff and has been involved in many nasty industrial accidents so wear gloves--you have been warned.

 

[IsaacHayes]

Re: Don\'t settle for tape or sputtering paint!

I agree that the source of light is the point you want to manipulate first. If you blur the point source of light to a smoother pattern before it is focused, your're not loosing any focusing than if you were to toy with the lens/reflector. The light is still lambertan wether or not you frost the bulb. But if you blur the reflector/lens, then you scatter the light and loose your throw...

 

[PaulW]

Re: Don\'t settle for tape or sputtering paint!

Hi bfg9000. Congratulations on your first post. I hope we hear more from you. There's more information about your suggestion here.

 

[bfg9000]

Re: Don\'t settle for tape or sputtering paint!

Wow I did search the forums for "etch" and "frosted" but apparently didn't look far enough back in time. Good to know that many of us think alike--I was really happy to be able to so completely clean up the beams in even my oldest 2D flashlights and actually make them usable again. Those all have 2V 1.2A eveready rechargable bulbs with clear facets on the bulb glass itself--which had projected a disco-ball effect before! I'm so pleased with the new beams that I can now consider 8xAA mods for them!

 

[Spacemarine]

Re: Don\'t settle for tape or sputtering paint!

[ QUOTE ]
IsaacHayes said:
If you blur the point source of light to a smoother pattern before it is focused, your're not loosing any focusing than if you were to toy with the lens/reflector.

[/ QUOTE ]

I'm sorry but I think that's not correct. If you frost the bulb, you no longer have a "point source of light" because now the whole bulb and not only the filament emits light. My prediction would be that the results of frosting the bulb instead of blurring the reflector/lens would be that you loose much more throw.

And why should frosting the bulb not absorb anyy light like a coating does? Does anyone have any measurements to prove that claim?

 

[ACMarina]

Re: Don\'t settle for tape or sputtering paint!

Is this applicable to LEDs?

 

[PhotonBoy]

Re: Don\'t settle for tape or sputtering paint!

Fine sandpaper might be okay for LEDs. YMMV.

 

[PaulW]

Re: Don\'t settle for tape or sputtering paint!

[ QUOTE ]
bfg9000 said:
. . . I was really happy to be able to so completely clean up the beams in even my oldest 2D flashlights and actually make them usable again. . . .

[/ QUOTE ]
It's a nice feeling to see a beam improvement with such a simple trick. A while back there was concern about the beam of the SF A2. It had a large circle of white light around the spill. I looked at the light when the batteries were low and found that the frosted tip of the bulb did not obscure the filament in this area of the beam pattern. I frosted a ring that extended the natural frosting -- just a hair's width. After that, the circle of light was gone and the beam was perfect. I posted what I did in this thread.

Paul

 

[Braddah_Bill]

Re: Don\'t settle for tape or sputtering paint!

[ QUOTE ]
Spacemarine said:
[ QUOTE ]
IsaacHayes said:
If you blur the point source of light to a smoother pattern before it is focused, your're not loosing any focusing than if you were to toy with the lens/reflector.

[/ QUOTE ]

I'm sorry but I think that's not correct. If you frost the bulb, you no longer have a "point source of light" because now the whole bulb and not only the filament emits light. My prediction would be that the results of frosting the bulb instead of blurring the reflector/lens would be that you loose much more throw.

And why should frosting the bulb not absorb anyy light like a coating does? Does anyone have any measurements to prove that claim?

[/ QUOTE ]

Just for kicks while watching the evening news I took some 150 grit wood sand paper and sanded a KPR112 bulb and was able to put a light frost (for lack of a better word) in about 15 minutes. I got the same effect as when I used WriteRight flim....a very smooth flood like beam...but IMHO I dont think it will throw as far as when the bulb was clear....at least thats what I thought in my eyeball back yard test last night.

Aloha,
Bill

 

[Mattman]

Re: Don\'t settle for tape or sputtering paint!

Like a sputtered or faceted reflector, the slight scattering of light that the sanded or frosted bulb creates should cut down on throw a little bit. Also, I would think that just sanding the bulb would block the transmission of some of the light within the bulb itself, also limiting your output and throw. I'll put this one in the category of "whatever floats your boat". If you want throw, leave everything stock. If you want better beam patterns, sputter, sand, frost and tinker to your heart's content. Luckily, bulbs of this kind are really cheap, so we can have lots of fun with them for just a few bucks.

 

[IsaacHayes]

Re: Don\'t settle for tape or sputtering paint!

spacemarine true, but there is less surface area that is being frosted. I would bet in a foggy situation, comparing a frosted bulb to a frosted lens, the lens would have less of a tight beam. Useing fog lets you "see" the beam shape/size/angle.

 

[jaids]

Re: Don\'t settle for tape or sputtering paint!

[ QUOTE ]
ACMarina said:
Is this applicable to LEDs?

[/ QUOTE ]
Perhaps but i find that the beam is perfect with my LEDs as long as they are centered properly.
My $0.02