# Can I grind down the tip of an LED?



## jimtyp (Jan 2, 2008)

I'm building a signal and trying to use a 5mm LED. It's just a little too long for the space I have to work with. A 3mm doesn't put out enough light to fill the lens. Is it okay to grind the tip down a bit?


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## toddalin (Jan 4, 2008)

Yes, most definately! Just go slow and keep testing it during the process. You may have some failures if you go too far, but LEDs are pretty cheap and after you do a couple, you'll know how far you can go. 

You can use an automotive plastic cleaner to polish out the lens when you get it to size.


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## dbodnar (Jan 2, 2008)

Jim - you can grind it down but you will lose the focused light that the rounded end provides - give it a try with an LED that you can afford to ruin and see how it works out - you should try to leave as smooth a surface as you can - do the initial plastic removal with a grinder or power sander then move to finer & finer paper to remove as many scratches as you can. 

Let us know how it works out for you. 

dave


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## Dr G (Jan 16, 2008)

Jim, 

I cut down a LED for a rotary becon on my engine--works great. (The orange color is Tamaya orange clear paint--just dipped the LED in). 









Sorry a little out of focus--but I think you get the idea. 

Matt


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## Torby (Jan 2, 2008)

Sure. 

Look close at your LED. Inside you see a chip on top of two metal leads. It'll be find as long as you don't get down that far. You can actually do quite a bit to an led to change its apperance.


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## Del Tapparo (Jan 4, 2008)

I hope it works. I just did my first one today. Haven't tested it yet, as some silicone adhesive is still drying. The LED is going behind a diffuser type of lens anyway, so what can it hurt?


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## John J (Dec 29, 2007)

I did not know you could do that./DesktopModules/NTForums/themes/mls/emoticons/shocked.gif Isn't amazing what you can leard from a bunch of wierdos who play with trains


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## Del Tapparo (Jan 4, 2008)

I just tested mine. (Still seeing spots from staring into a lit LED :blink 

I cut my LED flat using a rotary cut-off disk. No attempt to polish. 

The cut LED works fine, but the point of light seems to be about half the diameter of an uncut LED. The dome of the uncut LED magnifies the diameter. The uncut LED is brighter when viewing straight on, but has a narrower viewing angle. I think the cut LED now has a wider viewing angle and a more uniform intensity from straight on to an angle. 

Perhaps some reshaping of the dome and some polishing would produce better results, but that is more than I care to do. I think I prefer the look of the uncut LED, but this is good enough for me. I'll give it a try on the layout.


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## John J (Dec 29, 2007)

What about belving the side of the LED. Does that improve visability?


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## Del Tapparo (Jan 4, 2008)

I decided I didn't like the look from my cutoff LED, so I modified the housing to accept the length instead.


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## Cuhail (Dec 3, 2008)

I've cut down LEDs on a few occasions. After cutting them with a razor saw, I use a 4-sided finishing nail buffer. The 4-step buffers surfaces are perfect for getting a clear face on your LED. 
You can get the four-sided nail buffer anywhere from Wal-Mart to the dollar store. Ya just have to go into the makeup department, so, shoulders back and chin up! 

Cuhail


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## rkapuaala (Jan 3, 2008)

Would MEK work to cleanup the scratches after the first bit of sanding?


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## Dan Pierce (Jan 2, 2008)

My super walmart has 2000 and 4000 grit sand paper. you can polish paint with these.


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## Torby (Jan 2, 2008)

Wow. I thought 400 was fine!


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## toddalin (Jan 4, 2008)

Posted By rkapuaala on 12/22/2008 2:12 PM
Would MEK work to cleanup the scratches after the first bit of sanding?

Would probably soften/melt the plastic.


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## Semper Vaporo (Jan 2, 2008)

Posted By Torby on 12/23/2008 8:41 AM
Wow. I thought 400 was fine!


MicroMark sells a set of 6 sanding pads that go from 2,400 grit to 12,000 grit (yes, a "12" followed by 3 zeros, THIRTY times the 400 stuff that used to be called "fine" grit!), and you can also get a polish to get rid of the "scratches" left by that "aggressive" 12,000 stuff. They sell a Novus Try-It Pack that contains one set of these pads and 3 grades of a liquid polish (a thin toothpaste, a watery toothpaste and a thinner-than-water polish).

I used the Try-It pack to get rid of some scratches on the display of my radio scanner... could not read a couple of digits in the LCD window after the radio "fell over" ONCE when I set it down in some gravel! I started with the 2,400 grit and "OH DEAR!" the display looked all smeary like it had Vaseline all over it, but I then progressed up through the 3,200, 4,000, 6,000, 8,000 and then finally the 12,000 grits and then used the 3 grades of Novus polish on it and the display is like new.

Had to do it again not long ago... and I see I need to do it again! I have also used them to remove scratches from the plastic display screen cover on a digital camera.

I keep a few sets of the pads around to polish brass and Plexiglas after I have worked them on my lathe.

The 12,000 grit feels lots softer than my white dress shirt. but the surface has a lot more "cutting" ability to it. I have learned that I cannot skip a grit level... the 4,000 grit just won't take out the 2,400 grit scratches but the 3,200 will.

If it weren't for the number printed on the pads I could not tell by "feel" which of the pads of a set are the more aggressive. I found that before I use the side with the printed number I need to write the number on the edge so I can tell them apart.

The pads do eventually wear out, and once used on one material should not then be used on a different type. I have also learned to not let them touch each other after they are used... the "dust" from the lower numbered ones contaminate the higher numbered ones and will create scratches that the lower numbered grit was supposed to have removed.

Yeah, I used to think 400 was "fine", too!


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## njp (Dec 6, 2008)

I had to fix the scratched screen on a grandkids toy. I polished it with headlight plastic cover refurbisher. That got it noticably better.
As a final try, I coated the plastic with "Future" floor finish. It provides a self leveling acrylic coating and eliminates all but the deepest scratches and all hazing.

It is a Johnson and Johnson product, now markted under the name "Pledge with Future shine". New name, same stuff.

Check some of the plastic car ao airplane websites, they have got this stuff down to a science.
Nick


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## Torby (Jan 2, 2008)

Wonder if that's what I need for these plastic glasses...


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## wchasr (Jan 2, 2008)

Heh..."Future". It's the secret ingrediant in knife making at Cutco. We dip all the knives after polish and before assembly so they do not get scratched. Final step before inspection and packing is to wash them. If it works on 440a stainless it should work on everything else right? 

Chas


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