Fiber optics question (new question 7-26-08, pg2-post 11

[jonny5]

Is that each strand is the dia of 'mech. pencil lead' or all totaled?

If total and your fiber bundle is really that small you could drill a hole into the LED lens to receive the whole bundle then epoxy it in place.

Then maybe slip the whole deal into a nice sturdy piece of clear acrylic rod to protect it. It'd be clear so you can inspect if the light ever fails you''ll be able to see if the LEDs gone dead or the fibers came loose.


Also , wouldn't shink tubing present the same danger as hot glue?

To answer a few questions:

The power and light sources will be hidden under the base.

In all, I'll have 9 FO strands that are extremely thin, roughly the diameter of a pencil lead for a mechanical pencil.
The LED is one of those big ones, about 1/4th of an inch wide, so the straw idea probably won't work.

 

[division 6]

What I have seen others do on other forums and "how-to" videos is use 5 minute epoxy to attach the OF to the LED.

In some cases the LED is sanded flat then polished before adding the fibers.
Once set encase the unit in a tube or the shrink tubing making sure that the leads can't touch and short it out.

Also make sure to polish the ends of the fibers for better light flow.

D6

 

[dropshipbob]

How would I polish the FO ends? Not alot of area to work with.:lol

Johnny5, each strand is that diameter...really thin stuff. Even all together they're still not very thick.

JDH, that paints a perfect picture. I'll try that.:thumbsup

 

[division 6]

Get some really fine sanding film like 1500 grade or higher.

D6

 

[minieffects]

The brightness of a fiber optic is mostly going to depend on the source light. The brighter the source, the more light. If you use a lighter you can heat up the end and create a lens that will distribute more light at the end. Additionally if you kink the fiber it will cut down the amount of light transmitted. Typically for shooting miniatures we will use a halogen bulb with a piece of heat glass between the fibers and the lamp. there is also a cooling fan to keep the box cool. This is what we did for the Auriga in Alien Resureciton.



For what you are doing super bright leds work well but you must make sure that the fiber optic is properly aligned to the led to get the maximum amount of light.

Fiber optic

 

[Gigatron]

OK so the straw is used a a collar to join the fibers and the LED.
Got it. Yeah that works. still I'd line the inside with Aluminum foil to add
'reflective shinyness'.

There'd be no reason to line the inside of the straw. Fiber only transmits out the end. There may be some side emitting fiber out there for special application uses, but I doubt that's what DSB has managed to get his hands on.


As for polishing the ends, don't worry about. You're transmitting a simple light, not highspeed data. I'm a fiberoptic tech and work with gigabit fiber connections all day. I do everything from polishing to installation. Polishing the fiber with 1500 grit paper is like rubbing your car with rocks. Fiber polishing pads are up in the 5,000 range, just for the course polish. The finishing pads were up in the 20,000 range. Thankfully, we've moved to preassembled heads that are laser polished at the factory, so now I just assemble the heads on the strands (no more staring into a handheld microscope :thumbsup). For lowgrade fiber like this, just a nice flat, edge will suffice.

-Fred

 

[minieffects]

Yea I wouldnt waste time polishing, the lighter trick works fine and creates a small lens on the end. It also prevents the fiber from falling back into your model and gives you surface area to glue the fiber.

 

[LastBattlestar]

Thanks Scott and Fred for that information! I'm doing a test run with the FO lighting on my studio scale Galactica and am having problems with the el-cheapo fibre from a lamp. The off-axis viewing angle light throw is terrible and it was suggested to me to scuff the ends of the fibres to create more surface area.

I will have to go up to 1mm fibre for starters, but thanks to Fred's advice, I won't sand the ends!

Mike, Oz