I dedome while still hot after reflowing, (or after running the light briefly). I use tweezers to push, lift, and peel the dome off. It tends to come off in one piece when not cold. I also use a plastic toothpic to remove any dome bits that remain attached to the LED die.
this is how Artiet59 does it… imo his QTip technique works very well
there is also a post about slicing (I dont slice)
I prefer slicing. (see post above referenced by jon_slider)
A dedomed 519a is often too low in Duv and drops the CCT too much (for me).
With slicing, you can dial in your preferred CCT while getting ~1/2 of the duv reduction.
For example, if you want 4500k at –0.40 duv, shave a 5000k 519a to ~1.3mm or a 5700k 519a to ~1.1mm.
(This data taken with an Opple on 519a emitters from Clemence: R9080. Your results may vary.)
Slicing is easy with a little practice. I recommend an initial “thick” slice to get most of the dome off (~1.5mm) and then taking thin slices until desired height is achieved. A feeler gauge as discussed in other threads works great for this. I did 0.2mm slices and that worked well for making a smooth slice. Warming up the emitter first helps. Wiping the razor blade with a little silicone oil also helps. Worst case, you can always dedome if you don’t like the slice.
Also, a sliced dome tends to work better in many reflectors. Those designed for large domes like XML, XPL, or 351D, may not produce a good beam profile with a dedomed emitter, but work fine with a thicker slice.
For example, I did most of my testing with WK02 hosts that came with a SST-20. I found the best beam profile in these reflectors was a 519a sliced to 1.0 to 1.2mm.
Good luck!
FB
The pictures taken for the domed/dedomed 5700K 519A illustrate why I love the domed Nichia. The porcelain is still white, the background grey (I guess it truely is?) The scene illuminated by the dedomed LED shows a remarkable shift to orange/red.
With the A70 MINI I finally got something like a ‘grail LED’: The 5000K 519A. Perfect tint indoor and outdoor. Need to get the product code from Acebeam (thus far no success) and order some.
Edit: Lots!
I find that under 5000k, BLACK tends to appear more yellowish. If you want black to look black you need 5000k or 5700k. I prefer 5000k high CRI high LUX light in my machine shop. At home in the bedrooms and bathrooms I prefer INCAN on dimmers. In the kitchen and elsewhere, the 3000k no-flicker LED bulbs from Waveform.
I placed an order for a whole bunch of 519a in 4000K, 4500K and 5000K from the Convoy store.
Hope I like them. This will be my first experience with 519a. I got enough to experiment with dedoming them too.
I hope you enjoy them as much as I do…
Stock Sunwayman V11r, 520 lumens momentary max, 0.05 low
519a 3000K, 400 lumens momentary max, 0.05 low
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So, I have been using the 573 de-domed and love it! But a friend at work fell in love with the pure white of the TS10 at 5800k and very neutral Duv. So, I built him a T2 with one of my 5700k 573’s, but left the dome on. When I first powered it on I assumed that I had damaged the dome because visually it had a somewhat -Duv, not extreme but it was there and it felt to warm. Measured with my Opple it came in around the mid 5400k range and indeed a slight -Duv.
So, is the normal for the sm573?
this domed 5700K Opple tested at 5800K and duv –0.0012
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this dedomed 5700K tested at 4000K and duv –0.0042
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Finally, I got around to testing the 519a for myself. I replaced the emitters on my FWAA Ti from Nichia 219b sw45k to Nichia 519a sm573 DeDomed. Here are the results:
sw45k:
Max Lumens: 1260
ANSI Lumens: 424
CCT: 4549
CRI: 93.9
Duv: –0.0073
sm573DD:
Max Lumens: 1748
ANSI Lumens: 447
CCT:3999
CRI: 96.6
Duv: –0.0009
The tint is really nice:
Here is a comparative Full Runtime Chart on Turbo:
And here are the first 10 minutes, for greater detail:
Thank you very much for the detailed test data
sw45k:
Initial Max Lumens: 30% lower than the 519a
Lumens at 30 seconds: 5% lower than the 519a
both LEDs drop below 200 lumens in the first 40 seconds and then rebound slightly to sustain about 200 Lumens.
You are welcome jon_slider.
Please notice that as the dedomed 519a starts off at a higher output and yet slightly outlasts the 219b at high output. If one was to start the two emitter options at the same output level, the 519a would obviously sustain the output for longer. Similarly, if they were put at any level of output, as long as it is the same, the 519a will sustain it longer.
can you help define “longer”.
For example, how much longer is the 519a runtime, at the sustainable 200 lumens, than the sw45k?
Sorry jon_slider, I did not do any further tests.
My order of 519a leds just came in!
Now I just gotta decide what to try them in. And experiment with dedoming them.
Last night I installed a 4500K 519a in an Eagtac D25a on the stock aluminum star with stock driver. Not bad. Output was low, which was expected with this driver and no dedoming, but tint and CRI looked great.
Today I tried installing a 5000K 519a into my Tool Ti. This time I dedomed it. WOW!!! Good output, nice color temp, rosy tint, great CRI, dedoming was super-easy!!! 
I can see why this LED is so popular now.
So on these measure stock 3500k look already nice and quite rosy, there are others domed CCT from Convoy like it or even better?
Please excuse the interruption from a first post newly, but I’ve read this entire thread and am wowed at the scientific knowledge of this group.
I wanted to know about the 519A 5700K dedomed Noctigon KR4 that I just received today and took it out in the swamp next to my house to see what I ordered
I told Hank I wanted a floody bright light with good throw while wandering in Swamp at night.
Hank suggested a KR4 with 519A and 5700K and dedomed it.
All I can say (at 80 years old) is that I’m stunned at the fantastic color rendition and throw of such a nice flood beam.
I don’t know anything about the charts you show but I can attest to how well it works for this old man .
Thank you all for your persistence in chasing perfection.
I’m humbled by such erudite discussion.
Olight S1R Baton II with Nichia 519a sm573 DeDomed and 15 Degree Pebbled Optic. 650 Lumen,3800K, CRI 97, Duv –0.0087.
Olight S2R Baton II Peace with Nichia 519a sm353 DeDomed and 30 Degree Pebbled Optic. 550lm Lumen, 2700K, CRI 96, Duv –0.0022.
Olight Warrior Mini Autumn 2 with Nichia 519a sm453 DeDomed and 30 Degree Pebbled Optic.707lm, 3200K, CRI 97, Duv –0.0055.
Beautiful! Congrats on the Olight mods 
how do you get the bezel out without damaging the host?
and was the stock output really 1000 lumens before the LED swap?
Thank you :)
The bezel is the easiest to take out on the S1R Baton II. I use a box cutter blade and a hammer. You need to be patient and careful not to damage the coating, but it is not too hard to do.
The S2R Baton II and the Warrior Mini though are another story, as the bezel is internal and there is no external lip for the razor to go in and widen.