A Perfect Dedome?

Ooops, sorry, 2 connections just above the yellow pad - one connection is to the left of the trace cut (small connection), the other is to the right (large connection). The wire is supposed to connect the 2 connections but it's gone.

ESD protection. Not needed.

Took a C8 pill with Sinkpad still JBWelded in place, made about a dozen shallow cuts all over the dome, tied it to a copper wire and dropped it in the who-knows-how-old gas (at least a year old, from last year's lawnmower gas, has been used for around 15 de-domes and I forget how many reflectors that needed the orange peel stripped). An hour later...

...and after 5 minutes with my homemade plastic toothpick...

Scoring the dome with a razor makes it happen A LOT faster.

nice job with the clean up :smiley:

I’ll definately have to remember that little trick, would save a lot of time and eagerness and from the look of it provide the best result.

I use a plastic toothpick to clean mine up as well, it has tapered ends that come to a flat…works nicely for this. :wink:

Well done!

As I see it, the main purpose of removing the dome is to eliminate a converging lens because it reduces the effective focal length and therefore enlarges the throw hot spot.
So, maybe, the next step in that direction is to introduce a diverging element to increase the effective focal length and make a smaller spot. A common device of this sort is a Cassegrain telescope or microwave antenna. As a transmitting antenna, it focuses a finite size source to a small angular range, as we want for a thrower light.
Classically this would be done by putting a convex, ideally hyperbolic, mirror in front of the led and surrounding it with a parabolic mirror as usual. The light that misses the diverging mirror would form the spill, being out of focus for the main reflector. Other possible configurations would be adding a diverging lens to an aspheric or putting a diverging lens between a backwards facing led and a parabolic reflector. Something close to a classical Cassegrain seems the most compact.
The spill is partly focused, which may reduce the chance of blinding people near you.

yeah, nice, but who is going to develop all that, chinese, for their mas MAS MAS production :D right

A simple job doesn’t sound any harder than de-doming to me. Of course I am not doing that either, but I can talk.

The word salad is strong in this one, yes I agree muchly.

Not as much as in my OL DIY contest build… :wink:

I would like to thank Tom E on this thread…

Although I become your member just recently I was lurking this thread as a guest before…

Yes I have 100% rate so far and sometimes I don’t care to clean silicone residues and it still works perfect… I am testing each on aspherical lenses.

I recently tried to put fujik carefully around XP-G2 led emitter to protect those tiny wires from eventual drop or shock… I got that idea thanks to DBCstm and his black solder glue(page eight) that looks very interesting so I ordered some of that from ebay…

It is still on a shock test but I think Fujik can not harm to those tiny wires as when it cures has similar properties as pencil eraser we used so much in old school days…

Any idea of protecting led after de-doming would be much appreciated…

LED Seal - LED Supply.com

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I did another XPG2 with cuts all over the dome, dome floated off after 40 minutes, left it in for another hour and every bit of silicone was gone. Didn't even need to use the plastic scraper.

How about dedoming bare emitter before soldering it to al/cu base?

Having it mounted to something makes things a lot easier, even if you have to move it to a different board after the surgery.

that’s true, it’s easier to manipulate when you have a star to hold it, with bare emitter there is much more chance that something will go wrong but last time I tried to do XP-G dedoming I noticed something like rust on one side of the emitter, the place where emitter touches the al board, strange, because aluminum oxidation is white and this was something like black rust…

I have throw beam pictures that I will upload when I find a place to put them.
I glued a –116 mm focal length concave lens to black construction paper and stuck it over the led of a Sipik 68. I think the curved surface sat right on top of the dome. I unscrewed the bezel almost till it fell off to get it to focus. The XR-E image was smaller, but maybe not any brighter.
So the first order optics concept is demonstrated, but it remains to be seen if one can actually get more throw this way. I have not found an easy way to figure light loss.

With secondary lens:

Without secondary lens:

Sipik Sk68 w & w/o diverging secondary on left. UltraFire SK68 3 Mode on right.

Well this seems ok for LED wire protection but I think we can expect great lux drop if we put that direct on phosphor layer of emitter because it creates thin layer of silicone or something like that…

Maybe this thing could work without lux drop but only on phosphor layer
Liquid Glass Shield http://youtu.be/xufAQ8SHLxc

I believe that somewhere out there must be simple solution(better than wavien collar) of improving phosphor brightness of LED emitter like some kind of super glow phosphor adhesive or spray that would double lux/lumen…

But if some guy finds out how to do it he will probably keep that secret for himself :slight_smile:

Hi guys. I de domed my first LED last night! (an XM-L) I used one of those safety type razor blades and wet everything with WD40 to reduce friction of the blade going through the dome. It worked well but, I initially planned to use some silicon shock oil from my RC truck as the lube since it’s clearer and more heat resistant but, couldn’t find it at the time. My initial cut was lop sided (LED was slightly inaccessable) so had to make numerous cuts to get it right-ish. The end result was not a flat surface but a very slight dome. The LED was a neutral white something and it didn’t go through any colour shift when ‘de-domed’. Honestly, it’s pretty cool but, the beam is so thin (LED is in a maglite with a Mag LED reflector) that it’s almost annoying lol.

Do you guys dedome for fun or for practical reasons?

For me it’s about warming a too cool tint and narrowing the beam for better throw.

I just did some work on my Solarforce M3 head, removed the star and took the XM-L U2 off of the aluminum, reflowed it to copper then de-domed it in gasoline with the cutting method. It worked well, the dome broke up and eventually everything was clean but it still took around 4 hours. I then removed the driver and replaced it with an E1320 5 mode, no blinkies. Was seeing 3.45A at the tail. Thought about it for a bit, bypassed the springs with a 20ga wire and added 2 chips for a total reading now of 4.22A. Very happy with that, with the beam (whiter and narrower with considerably more throw), and with the almost white tint (it was too blue for me before). :slight_smile:

This is why we do it! lol

For me, it's all about throw - doubling the kcd usually - that's why I de-dome. I think it's great for XM-L2's because a little more than doubles kcd, but with XP-G2's, I'm seeing a reduction in amps for some reason, so not getting quite double. In a mod'ed out HD2010 or SS T08, simply awesome of 200 kcd or so. Just did a C8 fully mod'ed with a XP-G2 and measured 142 kcd. Also I've done 3 TN31's so far and get about 349 kcd as I measured (resistor mod and XM-L2 U2 on stock copper), but most likely it's higher at 360-370 kcd when measured further out at 15 meters or so.

If you are thinking of a dedicated thrower, than de-doming is a must. Still want to do my Crelant 7G9, because it does about 120 kcd now, and with adding little more amps and de-doming, should get 260-300 kcd I'm thinking.