# Easy DIY Beam Spread of Irix Icon II



## Bolster (Jun 15, 2011)

I like the Irix Icon II as a backup headlamp. Where else can you get 1xAA, 50 lumen, and a dial potentiometer for a little over $20? As Carrot said, "...the poor man's SF Saint." 

However for my use it has a fatal flaw...the narrow beam spread. Sort of like looking down a tunnel. The beam has a gradually receding margin, which makes actual measurement difficult, but if you try to measure the edge of the beam where it's about 50% as bright as the center (judging by eye), I calculate the beam about *24* degrees, across multiple trials. Might be perfect for reaching your feet (a trail hike at night), but it's pretty darned narrow for reaching the ends of your arms (hand-work). 

So after reviewing the standard CPF options...bead-blastiing, grinding the tops flat, applying an opaque epoxy, sanding the LEDs, or using frosted glass spray, I chose the easiest for this job...the spray. First, a before shot: 







As a "control," I pasted some frosted "invisible" style scotch tape across the LEDs and remeasured the beam spread...that took the beam spread to *31* degrees, averaged across several trials. I was curious whether the spray would do as well (or perhaps worse) than tape. 

Then using calipers, I made a paper mask in Illustrator. (If you want a copy of this mask to do the same on your Icon II, just PM me and I'll send you a PDF of it.) Cut out the tiny circles with an exacto knife, and tape in place over the LEDs. This is a stupid photo but you get the idea: 






Cleaned the tops of the LEDs with alcohol, then sprayed with $5 can of Rust-Oleum Frosted Glass Semi Transparent finish. Wait 2 minutes, and hit it again with another coat, as per instructions. Wait 10 minutes and it's dry, peel off the mask, and here's what it looks like afterwards: 






Now for the measurements...the beam was now spread enough I found it very challenging to find where the 50% dropoff point was. At 24" from the wall I was measuring, across 5 trials, 18, 22, 21, 20, and 20 inches of diameter. That's a lot of variance, showing how much trouble I was having finding the "50% edge" of the beam. (But it sure was wider than the 9.5-10" dia beam I was measuring at first.) Take the average, trig the numbers, and that comes to *45* degrees of beam, for the central portion, then fading "spill" to the sides. So in use, it seems somewhat wider. It passes the reading test. I can read a book without turning my head to re-aim the beam. Thumb-up. 

It's more useable for my purposes now. Obviously I've lost some throw. I can't tell how many lumen I've lost, but my hunch is less than with the tape. When I use it in the dark it still seems "plenty bright," which was also my opinion pre-modification. I expect the finish to wear off with time, which will mean another application of spray. I don't know how tough it is, actually. Maybe it'll be better than I think. 

Finally, it's interesting to note that the frost spray is considerably more efficient at spreading a beam than is the invisible-style frosted tape. I wasn't expecting that. 

Beam looks the same before and after, just wider. Which means I have to re-aim it less often. And I can no longer pick out blue and yellow artifacts as before. It's still a directional flood, but I now consider it a decent backup for my H501s. In fact, I may get another. 

(Posted here because I thought the headlampers would find it more interesting than the modifiers.)


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## gcbryan (Jun 16, 2011)

I love a project...especially of the simple variety!

Does the frosted treatment wash off easily? Would this be something you would do for an outdoor hiking headlamp as well?

You mentioned that it spread the beam more than tape. I would have predicted that from looking at the finished product. I would be surprised however if the tape reduced the lumen output more than the frosting. 

I have tape of both headlamps and one small flashlight and it doesn't seem to reduce the output all that much (to me).

Nice project. I haven't read anything about the Irix Icon before so now I'm off to read the review I just found here on CPF.


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## Bolster (Jun 16, 2011)

The frost finish isn't water based; it's a product with solvent, is harmful to breathe, and dries very quickly. I'm guessing a lacquer product. Removal is with lacquer thinner or acetone. Also, instructions say it's OK to wash the painted surfaces with soap and water, which won't remove the frosting. So it's likely OK for wet applications (not sure the Icon is, though!) 

I can't say for certain if the frost finish reduces the output less than tape, I wasn't able to get the same sort of before-after comparison as with the tape, but generally a rattle can painted finish is not as thick as tape is. I'm just pleased it diffracts as well as it does, being as thin as it is. 

Give this a try on your lights that you've taped, you may be pleased; it worked better than I expected. For a really pro treatment, just do the inside of the lens. 

Maybe if I have time I can try to test light loss between tape and frost finish...provided my light meter is sensitive enough.


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## gcbryan (Jun 16, 2011)

I read the review now and saw the beam shots. I now can see why you're modifying it!

The tape works best for me where I've used it and it's reversible. On the Storm I already have flood emitters (wide by your standards even) but the spot beam was just a little ugly so tape kept it directional but just a bit more diffused. I wasn't trying to make that a true flood beam.

The EOS I think is more like what you're dealing with on the Icon. It felt to me like looking through a tunnel. Tape helped there. It didn't make it a pure flood beam but again that wasn't what I was after. Both of my headlamps are for hiking.

With flashlights I've only taped one small cheap angle light. With a larger P60 XP-G type light I put some diffusion material from an old dive light behind the lens. It will light up my entire backyard with true flood.

I don't remember if you have any angle info for the Storm on flood mode but since it has two emitters (one on each side) it definitely has an angle wider than my peripheral vision. When I'm outside and move around I don't see the end of the beam. It just feels like it's a full moon night. It wouldn't be bright enough for you however as it's only 25 lumen in that mode.


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## Bolster (Jun 16, 2011)

gcbryan said:


> I don't remember if you have any angle info for the Storm on flood mode but since it has two emitters (one on each side) it definitely has an angle wider than my peripheral vision.



I don't, and I wish I did. It sounds great. If you feel like measuring it, I'll run the numbers. With dark adapted eyes, 25 lumen would be more than enough for task lighting.


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## gcbryan (Jun 16, 2011)

Bolster said:


> I don't, and I wish I did. It sounds great. If you feel like measuring it, I'll run the numbers. With dark adapted eyes, 25 lumen would be more than enough for task lighting.


 
Two feet from the wall the beam and 16 feet across. Cut that in half for the more usable portion.

That's the best I could do since 25 lumens spread out like that has no edge. To get the 16 foot figure I had to tilt the light from side to side to create movement to see where the light ended. The more usable portion would be more like 8 feet across.

This is about as good as I can do. The light just trails off to nothing eventually but there is no distinct edge at all. Since there are two leds (one on either side of the main emitter) it makes for a very wide angle.


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## rojos (Jul 29, 2012)

Bolster, how durable has the spray been for you so far? Have you needed to touch it up since last year?


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## Bolster (Aug 2, 2012)

rojos said:


> Bolster, how durable has the spray been for you so far? Have you needed to touch it up since last year?



No touchup needed, but it has not seen rough use where it would be scraped around.


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## jinya1004 (Aug 9, 2012)

Bolster, thanks for this thread,


I followed your directions step by step, but noticed that my frosting comes off pretty easily. Other than the alcohol did you prep the LEDs in anyway?

The coating comes off even when I put the rubber surround back on. I'll post pics of my experience when I get home.


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## Bolster (Aug 10, 2012)

jinya1004 said:


> Other than the alcohol did you prep the LEDs in anyway?



Hate to admit that with 14 months passing I don't remember exactly how I prepped the LEDs. Is it possible I hit the LEDs with fine steel wool first? Maybe. I don't recollect doing that, but that would certainly help adhesion. The frost product I purchased is specifically for painting on glass, so one would expect it to adhere, given the proper preparation. Acetone would remove more oil and grease than would alcohol, but you'd have to be careful it didn't contact the plastic anywhere.


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## rojos (Sep 15, 2012)

FYI to future users. Although the Rustoleum spray frosting is fairly durable, it can chip off if you're not careful. If this happens, you can wipe off the frosting with isopropyl alcohol and start over. If you want to be thorough, immerse the LEDs in alcohol and the frosting will melt off completely without damaging the LED dome underneath.

I used 92% solution and it worked great. I don't know if 70% will be as effective.


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