fiber optic lensing

bruce53176 · Post by **bruce53176** » Mon Sep 28, 2009 8:17 am

I have seen people talk about a process I believe is called lensing the ends of fiber optic strands. I was wondering if anyone had a process for doing this? I obviously can't use a lighter to melt the end so what would be the best way to heat up the end and what would be the best way to shape the end once it is heated up?

DLMatthys · Post by **DLMatthys** » Mon Sep 28, 2009 9:33 am

Other heat sourses I've used to lens FO is a candle and lit cigarettes...but that also requires a ligther. Do you have fire in your part of the world ? jk

Then there is matches, soldurig irons, car cigarette lighters, stoves both gas and elelctric. Well anything that gives off heat and can burn you.

After its melted to a little half dome...like the shape of a mushroom, it can be shaped with files and sandpaper.

Chacal · Post by **Chacal** » Mon Sep 28, 2009 5:08 pm

Around these parts, the process is known as 'mushrooming' the fiber.

The best, most reliable heat source is indeed a cigarette lighter. Yes, you can use any heat source, but lighters are superior because they can be put off easily (try that with a soldering iron!) and the flame can be controlled with great precision (candles are a close second).

When using a lighter, the trick is to let the end of the fiber you want to 'mushroom' close to the fire, not into the fire. The fire is to be in front of the fiber (meaning the fiber points to the center of the fire), not under it. The heat that will touch the fiber must be gentle: on scrap fiber, start with the flame far (two inches) then come slowly closer until the mushrooming occurs. Remember that distance for your next time, as it will be pretty much the same for your particular setup (lighters are all a bit different, fibers behave differently according to diameter and so forth).

bruce53176 · Post by **bruce53176** » Mon Sep 28, 2009 6:21 pm

Wow ok I didn't think that a lighter would be a good choice because of the black smoke that they can sometimes give off. Well in that case that sounds pretty easy and I really feel like a noob.

en'til Zog · Post by **en'til Zog** » Mon Sep 28, 2009 7:57 pm

Dude, we ALL started out as noobs!

Welcome to the madness.

USS Atlantis · Post by **USS Atlantis** » Mon Sep 28, 2009 7:59 pm

bruce53176 wrote:Wow ok I didn't think that a lighter would be a good choice because of the black smoke that they can sometimes give off. Well in that case that sounds pretty easy and I really feel like a noob.

We were all in that boat at one time

And you don't use the tip of the flame - thats where the black smoke comes from - bring the SIDE of the lighter flame near the fiber end

seam-filler · Post by **seam-filler** » Tue Sep 29, 2009 2:43 am

Use a butane lighter, not a gas/petrol lighter. Butane burns a lot cleaner with less of the black smoke.

Another heat source is a microflame which is really controllable - but probably not worth buying just to lens FO.

I've not had any trouble with using soldering irons for lensing FO (or stretching sprue for that matter) - I clamp the iron in place and bring the FO to the iron. I can move it away quick enough when I've done. Using a lighter pretty much means that one hand is busy holding the lighter.

bruce53176 · Post by **bruce53176** » Tue Sep 29, 2009 8:12 pm

Thanks guys all really great suggestions. I'll let you how things turn out.

Vargen666 · Post by **Vargen666** » Wed Sep 30, 2009 1:35 pm

Hmm, this sounds interesting. But what is "mushrooming" fibers used for? To create spotlights or something?

Kylwell · Post by **Kylwell** » Wed Sep 30, 2009 1:41 pm

It helps the light go from a tiny little pinprick of light to something a little larger with a wider viewing area.

starmanmm · Post by **starmanmm** » Wed Sep 30, 2009 7:31 pm

I have always mushroomed a FO using a candle. Easy.

DLMatthys · Post by **DLMatthys** » Thu Oct 01, 2009 9:56 am

bruce53176 wrote: because of the black smoke that they can sometimes give off.

The idea is to melt it...not burn it.

Madman Lighting · Post by **Madman Lighting** » Thu Oct 01, 2009 3:17 pm

The science behind it goes like this:

If the end of the fiber is not polished or melted smooth, the light coming out is scattered by the rough, faceted end. Its worse trying to get light INTO an unpolished end, the light get scattered at the incoming end before its got a chance to run down the fiber.

I usually polish or melt or mushroom the incoming end with a soldering iron, just cause I always have one around.

The more I dig into the whole fiber game the more I like it. One supplier I found has large diameter side strip glow fiber, so you can edge light your product from a protected source. This is really cool for lighting the edge of stair steps in swimming pools, or lighting the edge of your kitchen countertops.

Neat stuff!

-John