Grinding/Sanding larger bulbs?

kronos6948 · Post by **kronos6948** » Tue Jan 05, 2010 5:55 pm

How would one go about doing this without ruining the bulb?

Reason why I'm asking is because I scored what I thought was a good hit...I found xmas LEDs (an xmas net) at a Home Depot for 4 bucks. 70 "cool white" LEDs. Problem is, they're teardrop shaped with a crosshatch pattern on them.

They're not super bright, but I think they'd be the perfect brightness for windows and nacelles, but due to the pattern embossed on them, they throw light in all directions instead of concentrating it.

Chacal · Post by **Chacal** » Tue Jan 05, 2010 6:14 pm

As long as you:

a) Don't overheat the LED bulb by sanding/Dremelling; and

b) Don't get closer than 3/32" (or so) to the metal bits inside,

you'll be fine (and so Will the LEDs).

kronos6948 · Post by **kronos6948** » Tue Jan 05, 2010 6:44 pm

Chacal wrote:As long as you:

a) Don't overheat the LED bulb by sanding/Dremelling; and

b) Don't get closer than 3/32" (or so) to the metal bits inside,

you'll be fine (and so Will the LEDs).

So, how would I do this safely? I do have a variable speed dremel like tool...but I don't want to overheat the bulbs. Is it going to be the old fashioned sand by hand until I get the desired shape, and then sand with finer and finer grits until it's polished? Or is there a faster method?

USS Atlantis · Post by **USS Atlantis** » Tue Jan 05, 2010 8:12 pm

How big are those teardrops?

A set of lights I picked up last year were teardrop shaped with cross-hatching - but that was just a plastic lens mounted around the actual LED - pulled those teardrops completely off to get at the LED underneath

kronos6948 · Post by **kronos6948** » Tue Jan 05, 2010 8:38 pm

OOOH!! GOOD CALL!!

They come right off!!

Thanks!!

kronos6948 · Post by **kronos6948** » Tue Jan 05, 2010 8:58 pm

Ok, new question...These have a flat top to them, which when shone directly on stuff, they give off a dark spot, and a bright ring. I'm assuming it's because they're not dome shaped.

Now, these things are TINY. One bulb fits PERFECTLY in the 1/350 Enterprise's saucer section marker lights (the ones that are supposed to be red and green), and when held up to a tape measure, they're 3mm in diameter.

So, do I then grind them into a dome shape by hand with some fine grit sandpaper by rounding the flat edges?

Chacal · Post by **Chacal** » Wed Jan 06, 2010 6:14 am

Basically, yes.

You might get them to rough shape with a Dremel, though. Just a touch against a sanding drum (so they don't overheat), turn them a bit, another touch... Of course, you have to hold the LEDs with needle-nose pliers or something like that.

After the shape is roughly sanded, you go in manually to finish shaping it.

swhite228 · Post by **swhite228** » Thu Jan 28, 2010 6:43 pm

kronos6948 wrote:Ok, new question...These have a flat top to them, which when shone directly on stuff, they give off a dark spot, and a bright ring. I'm assuming it's because they're not dome shaped.

Dose the flat top have a cone shape in it?
If so the led uses the cone to reflect light out the sides of the led. You would need to sand off the cone to get rid of the drk spot.

kronos6948 wrote:So, do I then grind them into a dome shape by hand with some fine grit sandpaper by rounding the flat edges?

Yep, or look for clear half spheres the same diamiter as the led (jewlery sectiom of craft store) to glue on the flattened end.

MillenniumFalsehood · Post by **MillenniumFalsehood** » Sat Jan 30, 2010 2:04 am

Chacal wrote:Basically, yes.

You might get them to rough shape with a Dremel, though. Just a touch against a sanding drum (so they don't overheat), turn them a bit, another touch... Of course, you have to hold the LEDs with needle-nose pliers or something like that.

After the shape is roughly sanded, you go in manually to finish shaping it.

It's a touch easier to chuck them in a drill, mount it in a vise, tie the trigger, and sand away.