Sanding down LED dome?

I was playign with one of my stock LED mags and I was wonderign what would happen if I sanded down the dome on the LED? How would that effect the light? I have seen sanded LEDS before but before I try it I wanted to ask your guys opinions...What are the pros and cons of doing this? Also would that help get rid of artifacts? I am looking to smooth out the beam for a nice flood light that still has some throw...Any help and or opinions is appreciated!

I can tell you this. It won't get rid of any artifacts. As for beam pattern that's in the air. Just so you know those domes aren't very robust as they can't take that much abuse.

Oh ok...thanks for the help, I might not do it now...I know I dont want it falling off or anything...

cutlerylover said:

Oh ok...thanks for the help, I might not do it now...I know I dont want it falling off or anything...

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really depends on whether the dome is solid or jelly, but if you sand it too hard I suppose you will see minor artifacts if your using a smooth reflector. i accidently sanded [should I say scraped] mine...but under the chipped and marred window of my mag3D i cant tell the difference

dont try sanding on the jelly, they tend to fall off if you exert force a certain way, I ruined a K2 die like this..

I've only done it with 5mm LEDs and I don't sand but scuff the surface/tip of the LED. It reduces artifacts due to uneven phosphor coating (blue in the center and yellowish corona) and widens the beam. It also reduces total light output slightly. If you're sanding to remove dome material, it'll have to be a very symmetrical job or else you'll have an uneven beam pattern.

The uneven beam pattern in the MagLED may be due to the reflector and not the LED itself. I don't know if scuffing the LED's surface will help with that. Maybe you can go the old fashioned way and stick scotch satin tape over the window of the light to diffuse the light.

Ok thanks guys, I think I will just leave it be for now...I was thinking about using a medium stippled aluminum reflector to smooth out the beam into more of a flood light but I will lose the baility to focu the beam since the only reflector I have is camless...I might just have to buy a cammed stippled reflector to get what I want...Thanks again for the help!

I've tried sanding down a couple of 5 mm SMJ LED's.

1 was an uncut one, the other was cut, worked like a charm, smoothed the beam quite well, especially the uncut one. The cut one was in a minimag upgrade, it helped a bit.

I tried doing so on a Cree star, had no luck, I think the material is harder... ended up using some PDA film to diffuse the light instead.

Oh yeah, I used steel wool or a scotchbright pad, much gentler than sandpaper and required almost no pressure on the 5 mm leds.

What do they make the domes out of? I tried using acetone to frost the 5 mm led (does that to clear plastics) but it did nothing...

If you did sand the dome you would need to polish it up as well

I have used a hack saw then put clear nail polish on. It works.

TORCH_BOY said:

If you did sand the dome you would need to polish it up as well

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I have sanded 5mm LEDs with 600 grit sand paper (extremely fine) in all sorts of things like LED night lights, coin cell lights, and reading lights. Why manufacturers use highly focused LEDs in flood light applications is beyond me. However, I woudln't mess with sanding the power LEDs. I've accidentally broken off the entire ring/dome assembly from a Cree, and it makes the entire thing a lot uglier -- ie more uneven mixing, and a tendency to project a square image of the LED die. Those domes already throw a lot of light to the side for flood, so I don't really see the need to sand them down (unlike tightly focused LEDs)

Hi there,

Did anyone ever try that acrylic plastic glue that comes in a clear liquid form?
It looks almost like water, but it dries really fast, and it is often used for a
welding glue to stick acrylic plastic together to make things like fish tanks.
One dip in this might fog the plastic enough to diffuse it just right, once
it dries, which takes about 15 seconds.

gunga said:

I tried doing so on a Cree star, had no luck, I think the material is harder... ended up using some PDA film to diffuse the light instead.

...

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from what i saw/ read the cree dome is glass, with a gell Under it, a thin dome of glass over it.
it can get cracked, and the gel underneath can get air gaps and then would have a altered light distribution.


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a piece of "transparency" tape is a quick way to add minor diffusion to anything, tops of domes, face of the front glass, top of optics, or even internally in optics.

its a good way to non-permanentally see what the effects might be, its also a quick way to turn a useless (for the situation) spot , into a wide view, like on a spotty headlight. put a fold over TAB on the end of it and you can rip it back off easily.

To be perfectly honest, I just don't understand why people are inclined to get items like textured reflectors or otherwise modify the MagLED modules. The output seems to be relatively smooth with these modules once they've been focused to a spot; you just don't get the horrible batwing output that you get from the incandescent bulbs.

cutlerylover said:

I was playign with one of my stock LED mags and I was wonderign what would happen if I sanded down the dome on the LED?

Click to expand...

cutlerylover said:

I was playign with one of my stock LED mags and I was wonderign what would happen if I sanded down the dome on the LED? How would that effect the light? I have seen sanded LEDS before but before I try it I wanted to ask your guys opinions...What are the pros and cons of doing this? Also would that help get rid of artifacts? I am looking to smooth out the beam for a nice flood light that still has some throw...Any help and or opinions is appreciated!

Click to expand...

I've only sanded down 5mm LEDS - the smell of burning epoxy is horrible! This may you can make the LED's from Photon clones with dead batteries fit a solitaire.

If you use a nylon brush on a dremel you can restore the epoxy to water clearness. Might work on Luxeon LED's - I'd not try it on gel ones as all you're likely to do is make a horrible mess

dulridge said:

If you use a nylon brush on a dremel you can restore the epoxy to water clearness.

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Thanks. I never figured out what they can be used for.

Brighteyez said:

To be perfectly honest, I just don't understand why people are inclined to get items like textured reflectors or otherwise modify the MagLED modules. The output seems to be relatively smooth with these modules once they've been focused to a spot; you just don't get the horrible batwing output that you get from the incandescent bulbs.

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i can think of another reason.
when you have certian LEDs, they have a concentration pattern already, like 10-60 to as high as 120*. This already optically concentrated light goes out the front of the light un-changed.
now that makes for good total output, but if your trying to get all of the light concentrated by the reflector, stopping the initial optical concentration, would have more of it hitting the reflector.
a incan bulb is (more like) a ball of light without optical concentration, by ruining the concentration on the original led, you would have it act more like a bulb.