hi, I managed to make a quite neat (HD, if you watch it in youtube) video of my latest dedoming. There is a vast thread ('a perfect dedome' by Tom E) mainly on the gasoline method, but if you are not too slow and have a steady hand, hot dedoming is much faster and may be more convenient. I thought I'd show it, it may be useful to someone ('in a somewhat bizar set of circumstances', to cite Tom Lehrer in his introduction to 'The Element Song' )
What you see in the video is a Sinkpad on which seconds ago a XP-G2 (R5 3D-tint) is reflowed (you can even see the hardening of the solder), I hold the board down with my finger on a piece of cardboard (because it is still very hot) and the dome is removed with a straight-edge scalpel. The dedoming is not perfect because during removal I touch the edge of the die with the scalpel and remove a tiny bit of phosfor which can be seen left on the removed dome (only if you know that that happened, you can find that tiny bit of blue in the beam of the flashlight this board is in now).
Very nice, djozz! Great demonstration. The trick to this working on the 2nd gen LEDs is the bond wires not sticking up and into the dome like they did on the 1st gen chips. What do you use to heat the LED? Do you just run it for a minute or heat it up with an iron or something?
The second generation still has the wires sticking up, but the warm silocone gets soft enough so that the wires cut through it. I use a rebuild 12V solder iron on a bench power supply for reflowing, I have described it here a while ago (my hands have become steadier since then :-) )
Pretty much exactly the way I do it.
I cut into the dome a bit instead of the flat though. And instead of pushing, I lift a bit until I see the dome separate then move real slowly.
Heat makes all the difference! Thanks for the vid.
Nice video. Appreciate effort. But as you said angry blue will appear on the place you scratched. That will not be to bad for reflector but it will be total disaster for aspheric.
Yes it is really hard to perfectly de dome with this method especially if you got to set up the camera and have still hand for audience
In fact it is very hard to de dome this way in any case because you got to have good eyes and calm hands. I personally screwed up(more like partial screw up like on your video) more than 10 emitters.
Don’t be angry on me for being brutal honest but this is only de-doming method for real pro.
Why? You can be real pro in this like Vinhnguyen( I bet he also had his own failure rate) but:
- Unnecessary heating of emitter can not be to good for emitter health.
- Sharp knife/razor/scalpel in combination with excellent sight and calm hand makes this method unusable at least for 40% of flashaholic population
- It leaves messy surface around emitter after de-doming
Terrible felling in your stomach after you screw up your project… it can ruin your nerves and will for de-doming
Been there, done that until I saw TomE gasoline de-doming method (as a lurker). God bless TomE.
Weather you are noob or pro this is:
- 100 % simple method
- 100% successful de dome rate
- 100% clean surface(after isoproply alcohol bath) like it never had dome at first place
U can even de dome whole drop ins(after building them)
Only minus is time(4-5 hours) which you can shorten by simple side cuts of dome with scalpel. So it will fell of in 30-50 minutes.
That was a great video for me, i didn’t understand how it wouldn’t rip the wires out aswell when people said “just heat it up and pull it off” but seeing that and how gloopy the dome was gave me more of an understanding than reading all the written stuff. Thanks djozz.
I agree this method has plenty more risk involved damaging or altogether losing the emitter than the gasoline method. Nevertheless i have done about 10 dedomes like this thusfar (xp-g2 and xp-e2, but I expect xm-l2's not to be harder, perhaps even easier) and have not lost any emitter, and this was the first one that lost a (tiny) bit of phosfor. What does help enormously is that I use a good stereo microscope to follow the dedome so that I can steer my movements very precisely (the video was shot through one of the two eyepieces, so with this dedome I did not have stereo view).
Maybe if you boil the emitter in gasoline or dunk a red hot emitter in gasoline you can have the best of both worlds (this life and the after life?)… or not… J)
With this method you could get free face plastic surgery in hospital. Or if dunked in canister Peace and prosperity in haven 0:) or misery and poverty in hell J) depends how good/bad you were in your life.
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Yes.