So tried unleaded petrol 10% ethanol.
Suspended the led at about 7pm last night. Took it out at 7 tonight. . Petrol had evaporated quite a bit and was no longer touching the led.
So side note… when putting led in petrol suspended about 5mm below surface seems to work well.
Did not need to cut anything… tipped the led on its side, touched it with the tip of the blade and the dome just fell off…
Easy as pie…
Slight greenish tint to the light now. Seems a bit brighter but i don’t have the gear to test so thats just observation. Will have to test with a better light.
So tried unleaded petrol 10% ethanol.
Why do you only hot dedome LED’s when you are running them over 5A?
I have only de-domed two emitters…both with regular unleaded gasoline left overnight. Easy.
I just use the gas method, regular gas, in a capped jar to avoid evaporation. The time consuming thing is cleaning up the remnants of the silicone around the phosphor, if there is any left - sometimes they come out perfectly clean. To do that clean-up, I use toothpicks because they won't scratch the silver/gray surface. Metal tools will scratch it up. Must be careful to leave the 2 wires fully in tact, so usually I'll leave the silicone around those wires -- gets too risky. I use a 20X loop and a good light source (headlamp) when doing the toothpick clean-up.
The throw kcd value (not throw distance) will usually about double, if focused properly, while the total output (lumens) will drop between 10%-20%. The tint will turn a strong yellow with some green perhaps. A de-domed 1A will be more yellow than a 3C or 4D from what I've seen and others attest to. De-domed 3C's look even stronger yellow, so I limit the de-domed bins to 1A or 0D. Even 1C's are so-so.
I’ve de-domed 3 of them so far. The heat from the emitter does the trick. You have to run some leads so the mcpcb is off the sink and put a rolodex card on the backside so the clips don’t short out.
Look at which side the small leads are on. There’s another lead that connects the 2 sides counterclockwise to the main ones. Found it takes ~8 seconds on and the mcpcb is almost too hot to touch. Switch the light off and lift one corner at a time on the side with the leads. Don’t lift in the middle though, you want to lift at the corners only with an exacto knife. You’ll see the dome kind of peel up as it hits the yellow emitter. Turn it on and do the other corner peel up a bit.
Now on the 3rd burn you hit it from the other side, and peel the whole thing up. There’s no leads on that end to mess up. It should come off with one peel clean. There maybe some left around the main leads but leave that there. A 3 dollar 40x jewelers loupe lets you inspect the work.
The gas method sounds good too, but I’m scared xd If you get anything like specs on the emitter before install after soldering. You can take cheap packaging tape, the kind that doesn’t stick well, and just touch it on top with a corner of the tape, comes right off. The loop helps a lot.
I'm 100% with gas - done dozens.
Forgot to mention - I always clean up by squirting isopropyl alcohol directly on the phosphor and all over the LED - again, never any damage, never any particles left. Seems 100% safe -- dozens, never a problem. My thread here: A Perfect Dedome?
I too have done dozens that way and it’s the most reassuring way. The toothpick step is almost a must.
After discovering the hot de-dome method, I really haven’t gone back to using gas. I don’t like the smell of it. Or the smell of the alcohol to clean it. yuck. :Sp lol
Since the way I use the hot method has the emitter in the light, all heat sinking is in place. Pretty sure it takes 5A or more to really get a safe release without breaking bond wires. The only one I’ve had fail was under 5A. For me, this is a happy medium of safety margins. Hot de-doming outside of the light leaves the possibility of overheating the emitter. I like the KISS rule, because I can find ways to destroy these lights that no one else has discovered yet out of my sheer forgetfulness.
I use 2K thinners as my old man owns a panel and paint shop so I have plenty of it available. From what I have read about de-doming with petrol, the thinners is essentially the same just quicker. I find brand new LEDs take a bit longer than ones which have been used in the light for a while, however the longest I have waited for it to float off is about 2 hours.
Thats what I like to hear lsx, thinners just seems cleaner to me. Shall use it for next one.
I have a 1D in as throw. It’s not bad but it is more yellow when compared to my other lights. I should have went with 0D or 0A from the looks of the cool white chart. Where would you get those bins cheap? I don’t think I see them on on mountain electronics.
Has anyone noticed a difference in tint shift from using petrol than the peel method, which one creates less yellow tint afterwards? or is it all the same no matter what method you use? I wonder what original tint Vinh54 uses for his premium tint dedomes and what his rejection rate is.
Cheep hardware store plastic aspheric sacrificial lamb for thinners test..
Question... if dome does not just fall off.. above or below metal ring with knife ?
I got a Shocker modded by vinh once - most awful yellow dedomed tints I've seen. Think he dedomed 3C's or something. I've seen other dedomed lights by vinh and I don't notice any difference between his tints and my gas dedomed ones, but I think Dale has noticed differences. I've tried heat methods before and can't seem to get it right - gas is much easier for me.
Interesting to note now... djozz kind of proved our cheaper light meters (mine included) don't handle tint differences too well, and seems to record CW's higher, and NW/WW lower, so wonder if that's true for dedomed LED's, because I usually see a 20% loss in lumens after dedoming, so could be 5-10% loss simply from the poor quality light meter.
hmm i seem to remember people having difficulty de-doming the XR-E emitters…
I ripped mine off with pliers in an old C8 and the hotspot was painfully small. You don’t need to soak that in anything, just grab and twist. Might end up regretting it though, also ur pill is completely hollow so not the best for modding.
Wish had got the 1A bin now. Oh well I don’t even notice the tint until I fire up the big light right next to it. That is a really cool white flood though.
Good information on the bins Tom… For some reason I thought the 1D was better (xd I know), but now that I read the chart on cree, it’s worse for dedome than both 1A and 0D. Nice to know Vinhs lights are choob too. I thought he was supposed to be the booty buster of modded lights.
vinh is human, like the rest of us , he's not perfect on every mod. He doesn't do much in budget light mods lately - budget lights take the most time and effort for the least pay back, and he freely admits he's making money at this, he's not a hobbyist. In the past, he would be short parts and use what was on-hand, but also, the customer could have requested it that way too -- never sure of the whole story. If his high end lights modded sound like a price you'd pay retail, it's because he's a reseller now on a few brands, not all, and getting wholesale pricing - that's why he does the lights in larger batch's - economy of scale. Also, he basically partners up with other retailers to get good qty discounting - not huge I'm sure, but helps.
I use 1A's almost exclusively for dedoming because readily available in the highest bin of U2. T6 0D's used to be available, but you drop a full bin.
For best throw, you may want to consider XP-G2 and XP-E2's: XP-G2's for higher amps, XP-E2's for limited amps, up to about 2.5A. XP-E2's dedomed are the most proficient for running at the same amps, but since you can run XP-G2's and XM-L2's at higher amps, you will get more throw from those if able to do the high amps.
I like XM-L2's in zoomies because I want lots of light in flood mode, but if I'm targeting throw more, then XP-G2's at 4A or so. I find it hard to get much higher amps out of an XP-G2 on one cell because of it's higher Vf demand - higher than XM-L2's. There's all these trade-offs to consider, depending on what you want and what you have to work with .
Also Vinh left his engineering job to start full time modding. So he is trying to make a living from it as well.
I’ll order a XP-G2 and try it