It it safe to sand the clear part of a LED to make it smaller to fit into an HO model structure store front display?
Yes and no. I have trimmed down some 3 mm LEDs to flat front and also to decrease the diameter but do not go too far. This is a surface mount LED in the headlight and once a lens is fitted it would look just fine.
http://i1081.photobucket.com/albums/j348/locoi1sa/K5s%205698%20project/SAM_0562_zps82e1e836.jpg
I get my SMLEDs from Traintec LLC with the magnet wires attached already.
Pete
I pray every day I break even, Cause I can really use the money!
I started with nothing and still have most of it left!
Thanks for your response. You said yes and no. What is the no part? I am assuming you mean don't sand to deep so you expose metal? Is that correct?
Thanks
Brian
It's safe to sand off some of the outer coating of a 3mm (or 5mm) LED, but if you sand too deeply and get into the core it will be destroyed.
Your best bet would be to sand a small amount, test the LED to make sure it still works, then sand some more, etc.
Thank you!!
BRIANMARIE:
You can actually take a fair amount off of a 3mm LED before it will fail due to exposure of the internal components. As has been said, it is trial and error. One trick I use is to chuck the LED leads into a small variable speed drill and use a file to remove material as the LED spins. That results in a fairly even removal of the lense material.
There are some other alternatives:
One is to use SMD (Surface Mount Device) LEDs. They come in very small sizes. The size I prefer is referred to as '0603' meaning that the LED is .060" x .030", but there are 0402 sizes available as well. By comparison, a 3mm round LED is about .118" in diameter.
Another possibility is to use fiberoptic cable. A common size is about .019" in diameter but the cable can be flared by putting a little heat to it so you can make a "light bulb" sized to suit. Your light source can then be mounted out of sight.
To show you some examples of 0603LEDs and fiberoptic cables at work here is a truck I recently did. The headlights and signal lights use a very short piece of fiberoptic cable flared to form the lenses and the LEDs are epoxied directly behind the lenses on the inside of the body. The five clearance lights on the cab roof are also fiberoptic cable but the cables are run out the bottom of the truck where they are connected to a single LED:
Here you can see the bundle of cables coming out of the bottom of the truck on the left side. The wires feed the other eight LEDs mounted in the truck:
Working with the 0603 LEDs takes a little practise and patience. They are fussy. You can count on messing up about 1/4 of the time even with some experience.
If you want a more detailed explanation of how to attach wires and resistors please ask and we will be happy to oblige.
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
Dave,
Fantastic job on lighting that tractor,looks great..
If I may ask, where did you acquire,that White tractor??
Cheers,
Frank
If the LED is of the transparent color type, you can hold it up to the light and see the insides. You will see the metal poles where the leads come in, and you can also see the very fine whisker wire inside the gaoes from one pole into the top side of the actual semiconductor junction. So long as you do not disturb that, you can cut away or sand. You also con;t want to remove much material at the base where it supports the leads, otherwise they will flex too easily and break the fragile connection inside. The upper dome part can be turned down or sanded right down to amost touching that fine little wire though.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
zstripe Dave, Fantastic job on lighting that tractor,looks great.. If I may ask, where did you acquire,that White tractor?? Cheers, Frank
The SMD, LED is the way to go.
About twelve years ago I sanded down two lead, 3mm green/red bi-color LED's for single target signals. I used a cordless electric drill and a file. Flat fronted the LED also. Went two far on one. Used a drill press a few time where I worked as a machine mechanic.
First put the t of the LED in the chuck. Remove the flange. Reverse the LED and sand down the outside diameter and the front.
Lots of work.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
Frank:
slammin is correct. It is an older CMW model. As he said, they show up regularly on eBay. There are a few of them listed now but none with just the cab only. I searched for "White 3000" in HO trains.
EDIT: Forgot to say thanks for your kind words!