A Perfect Dedome?

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gords1001
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hey Tom, I should have been clearer…..hs1010. ….light meter lol, I need to start being able to measure results.

Tom E
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gords1001 wrote:
hey Tom, I should have been clearer.....hs1010. ....light meter lol, I need to start being able to measure results.

Oh, ok I went off track - thought u had typos...

 

Oh - crap!! Just did a C8 with de-domed XP-E2 with Nanjg at 3.15A (1 xtra 7135). So, I'm measuring 3.28A at the tailcap with a Pana PD, been tweak'n the LED position by unscrewing the pill and added a UCL lens. Got it up to 123 kcd now, but more tweak'n...

Edit: Ooops, only 89 kcd. Battery in the meter was goin, and replacement was drained too. Reading go up when that occurs with this meter, so, 89 kcd seems more realistic now. Seems it's the best I can do with a de-domed XP-E2 in this reflector at this amps. XP-G2's at higher amps can probably do better - my Convoy C8 does 125 kcd at 3.8 amps w/de-domed XP-G2.

manxbuggy1
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Wow! Now that is a pocket thrower!!

ohaya
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Tom E wrote:

Bort wrote:
comfychair wrote:

I finally killed one, but the gas didn’t do it. I had the bright idea to try rinsing in acetone instead of iso and even though it was just a quick dunk the phosphor went goofy and peeled up at the corners. LED still works, I managed to get all the phosphor off and now have a dangerously bright XML2 T6 UV emitter on a 16mm Sinkpad. Steve

So, don’t do what I did. Rinse in iso only.

this somewhat illustrates why i think solvents other then gas should be tried, i am curious if the gasoline in contact with the phosphor reduces its output at all, if someone did a test between several dedoming methods/solvents i would be very interested in the results

Well, the rule is double the throw (in kcd), and then some little more – so, maybe 105%-110% increase at throw in kcd. I know guys using other methods get this result – Manual Man here: http://budgetlightforum.com/node/20287). So for example, I’ve done 3 Small Sun T08’s, de-domed in gas. They all go from 95-100 kcd to 200-210 kcd. My results show this same approximate percent increase, so I’m thinking nothing is lost at all, if there is, it’s little. Now with XP-G2’s, I’ve had some disappointing results of not even getting 100%, but for some reason it seems like I’m losing amps after de-doming XP-G2’s – maybe they are that much cooler and drives up Vf, dunno.

Hi,

I posted on the “100% dedome” about an XP-G2 I’m trying to dedome in gasoline (see: http://budgetlightforum.com/node/13565?page=11#comment-422047). The dome came off easily, but left a thin uneven clear layer of something on the emitter surface.

I’m wondering if there is something about XP-G2s that causes this (different construction)?

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The dome came off clean, but left a bunch of gunk on the wires going to the die. When I did the XM-L the other day and broke a couple of the wires, gluing them back down with electrical liquid solder worked out ok. But this one has the wires on the positive side. What’s up with that? I was very careful not to break these and left some stuff there this time but still cleaned the rest up with needle pointed tweezers.

This T6 warmed up a bit, but it’s still a nice tint, slightly warm and I like it. Also made a handmade Titanium reflector for it which also turned out well, it now has a large spot with a good even amount of spill, with the blend being smooth and creamy.

Thanks for all the suggestions, gasoline rules!! Smile

Tom E
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ohaya - read the posts, never seen that before with an XP-G2 (residue), but mine soaked longer. I noticed in your pic one wire is gone - the ESD wire side wire, but supposedly that's not needed.

ohaya
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Tom E wrote:

ohaya - read the posts, never seen that before with an XP-G2 (residue), but mine soaked longer. I noticed in your pic one wire is gone – the ESD wire side wire, but supposedly that’s not needed.

Hi,

Sorry to bounce between this and the “100%” thread..

FYI, I think the problem was not waiting long enough. I did a longer re-soak, and that residue on the emitter itself disappeared after that longer soak (about 6+ hours, I think). On the XP-G2, I think, as far as I could see, there were only 2 wires, on the side where there’s a “+” on the PCB. I know that I’ve seen references to an ESD wire on XM-Ls, but the XP-G2 looks like (the wires are tiny, and I can barely see them with a 10x magnifying glass) there’re only 2 wires.

Were you referring to the pic of the XM-L on the “100%” thread?

I dedomed 2 XM-Ls the last couple of days.

An XM-L T6 (from Amazon) went in my shorty STL-V6, and is now giving me 122 Klux,

The other XM-L U3 (from FT) is in my Jacob A60, and is giving me 87 Klux now.

Tom E
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Post #1019 in the other thread, close-up pic of the XP-G2 de-domed:

 

I just so happend to have a de-domed XP-G2 on a 20mm Noctigon around, and those 2 pts above the emitter in the pic above are connected by a wire on mine - yours appear to be missing the wire.

ohaya
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Tom E wrote:

Post #1019 in the other thread, close-up pic of the XP-G2 de-domed:

 

I just so happend to have a de-domed XP-G2 on a 20mm Noctigon around, and those 2 pts above the emitter in the pic above are connected by a wire on mine – yours appear to be missing the wire.

When you say “above the emitter”, do you mean “above” in the pic (i.e., to the “right” of the + side of the emitter?

I guess I lucked out then, because I don’t remember seeing any wires there through this whole dedoming exercise, but the emitter still works :)!!

Tom E
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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.

comfychair
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ESD protection. Not needed.

comfychair
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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.

Sirius9
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nice job with the clean up Big Smile

 

DB Custom
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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!

Fritz t. Cat
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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.

Flashlight designers should look at lighthouses and pottery.
这些谁设计的手电筒应该看灯塔,以及在陶器。

Sirius9
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yeah, nice, but who is going to develop all that, chinese, for their mas MAS MAS production Big Smile right

 

Fritz t. Cat
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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.

Flashlight designers should look at lighthouses and pottery.
这些谁设计的手电筒应该看灯塔,以及在陶器。

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

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comfychair wrote:

The word salad is strong in this one

Not as much as in my OL DIY contest build… Wink

luminarium iaculator
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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…

comfychair
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LED Seal - LED Supply.com

-----

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.

Sirius9
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How about dedoming bare emitter before soldering it to al/cu base?

 

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

Sirius9
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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…

 

Fritz t. Cat
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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.

Flashlight designers should look at lighthouses and pottery.
这些谁设计的手电筒应该看灯塔,以及在陶器。

luminarium iaculator
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comfychair wrote:

LED Seal – LED Supply.com

——-

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.

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 Smile

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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?

My gratitude to those who are willing and able to help others (in whatever way you can)! Being human is more than just existing for yourself. Smile

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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). Smile

This is why we do it! lol

Tom E
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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.

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What is KCD? Right after reflow, when she’s still HOT, you can take a dental pick and pull up the XM-L2 dome very easy. Then less soak time in the fuel.
I reflow the emitter, tin the pads, secure the sinkpad in the pill, and flip of the dome in one heating.

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