Cree XP-G3, testing a S5 3A emitter

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will34
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Hoop wrote:
You might try the method commonly used to dedome other LED’s with embedded phosphor: by using a razor.

Instead of a razor could one use a cnc machine and a very sharp bit to shave the dome down to a very exact height? Would this give the flat dome a nice and even finish? just a wild guess…

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I’m excited about this new LED. Its performance results above are indeed promising for it to be a good thrower.

MEM, I look forward to your measurements.
My understanding of luminance (cd/mm^2) is that simple optics cannot change it. Most of my understanding on this subject is based on Dr. Jones thread: http://budgetlightforum.com/node/15818
In it I learned it’s not simply the removal of the magnifying dome which increases the throw. Removal of all of the silicone material results in a sort of light-recycling, which takes some of the light that would have left the LED at shallow angles and puts it back on the LED surface, increasing the luminance. In fact Dr. Jones compares it to a hemispherical reflecting aperture.
I’m a little fuzzy on the details. The test performed in this thread helped convince me.

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will34 wrote:
Instead of a razor could one use a cnc machine and a very sharp bit to shave the dome down to a very exact height? Would this give the flat dome a nice and even finish? just a wild guess…

I doubt this would work, dome is not that firm material, it’s silicone, even if you crank the speed up and set a really slow feed, it might just rip it off at some point, also, in case it works, I doubt you would get clean surface of the remaining silicone dome, no milling bit is sharper than razor + when you use razor idea is to do the job in one slice in order to achieve as flat surface as you can!

 

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gaston01 wrote:
Sirius9 wrote:
DavidEF wrote:
I would really like to know how to de-dome one of these.
+1

+1

+1

luminarium iaculator
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DavidEF wrote:
djozz wrote:
If the led can be succesfully dedomed after all (or if a HI version becomes available) it will be the top thrower led but with dome it has the competition of the XP-L Hi that is (at twice the price!) still the better performer.
MEM wrote:
These things are absolutely amazing when fully dedomed. I put one in a reflector light last night, and the lumens looked almost identical to the XPL next to it, but with a pure white hotspot 2/3 the size. I honestly would not trade the dedomed tint for anything I have seen yet dedomed. But 7-8 amps at max output? Holy…crap. YES! :Party:

So, de-domed properly, these should out-throw the old style XP-G2 S4 2B. Is that what you guys are saying? I’ve got a couple of the XP-G3 from the VOB group buy from Cutter. I would really like to know how to de-dome one of these. I’ve never had a XP-G2 S4 2B light. I’d really like to see what it’s like. Innocent

I think they are saying that XP-G3 emitter will out throw classic XP-G2 but only if we leave dome on.
And since 80% of us here do de doming, and expecting better performance with newer types of emitters it seems such performance upgrade will not happen with G3.

Wait until someone confirms kcd numbers in well known hosts. I know I would not be impressed with anything that will throw less than old production XP-G2 S4 2B de domed no matter how nice tint is.

Djozz sliced XP-G3 and did put it in well known and consistent performance aspheric host(B158) and results are really not good.

So when it will be pure clean de dome only 10-20% gain could be achieved(in my experience) and not even that will be enough to dethrone old de domed xpg2s42b

Djozz wrote:
How about dedoming this led that is build quite different than the XP-G2 ? Some first attempts by other BLF-members at hot dedoming or in gas were not promising. My own (limited skills !) first attempt at a sliced dome produced a working led but the throw was disappointing. See here. So for now, the ‘king of throw’ is still the ‘old type’ XP-G2 S4 2B, which unfortunately is not available anymore. http://budgetlightforum.com/comment/950071#comment-950071

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I believe the tests from Djozz are not that helpful in determining the g3s ability as it is not dedomed. It still has silicone covering the phosphor.

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PPDB22 wrote:
I believe the tests from Djozz are not that helpful in determining the g3s ability as it is not dedomed. It still has silicone covering the phosphor.

Luminarium has a tendency to form out-of-context passages from other authors into tidy, neat statements saying exactly what he wants to hear the first time he reads them. Silly Big Smile

Totally kidding, Luminarium! LOL

No but honestly, these fully dedomed G3s do something quite odd or even possibly incredible for some people I would imagine. After dedoming, the hotspot becomes about 5800-6000k. Reverse tint shift! It’s such a neat dual tone hotspot that I’ve begun to like it, a lot.

The die has more phosphor at edges, less in the center, like a dip when dedomed. I have macro photos I will post after I get back from the store of what that looks like.

My video of XPG3 full dedome using a diluted fuel mixture to slow the process down, is here: https://vimeo.com/167478193

I like bright lights, and I cannot lie.

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luminarium iaculator wrote:
DavidEF wrote:
djozz wrote:
If the led can be succesfully dedomed after all (or if a HI version becomes available) it will be the top thrower led but with dome it has the competition of the XP-L Hi that is (at twice the price!) still the better performer.
MEM wrote:
These things are absolutely amazing when fully dedomed. I put one in a reflector light last night, and the lumens looked almost identical to the XPL next to it, but with a pure white hotspot 2/3 the size. I honestly would not trade the dedomed tint for anything I have seen yet dedomed. But 7-8 amps at max output? Holy…crap. YES! :Party:

So, de-domed properly, these should out-throw the old style XP-G2 S4 2B. Is that what you guys are saying? I’ve got a couple of the XP-G3 from the VOB group buy from Cutter. I would really like to know how to de-dome one of these. I’ve never had a XP-G2 S4 2B light. I’d really like to see what it’s like. Innocent

I think they are saying that XP-G3 emitter will out throw classic XP-G2 but only if we leave dome on.
And since 80% of us here do de doming, and expecting better performance with newer types of emitters it seems such performance upgrade will not happen with G3.

Wait until someone confirms kcd numbers in well known hosts. I know I would not be impressed with anything that will throw less than old production XP-G2 S4 2B de domed no matter how nice tint is.

Djozz sliced XP-G3 and did put it in well known and consistent performance aspheric host(B158) and results are really not good.

So when it will be pure clean de dome only 10-20% gain could be achieved(in my experience) and not even that will be enough to dethrone old de domed xpg2s42b

Djozz wrote:
How about dedoming this led that is build quite different than the XP-G2 ? Some first attempts by other BLF-members at hot dedoming or in gas were not promising. My own (limited skills !) first attempt at a sliced dome produced a working led but the throw was disappointing. See here. So for now, the ‘king of throw’ is still the ‘old type’ XP-G2 S4 2B, which unfortunately is not available anymore. http://budgetlightforum.com/comment/950071#comment-950071

Why would you say that we are saying “with the dome on”, when I’m talking about a domeless LED? Once again you’re modifying what has been stated by others. Silly

A good experiment is not necessarily putting the LED in a host you are particularly fond of and getting one throw measurement from a sliced-dome LED. To be fair, a sliced LED is going to vary person to person, method to method, slice to slice.

A proper experiment would be using any host, with a “control LED” installed at the start. Then, other LEDs would be placed into the same host, directly comparing dedomed XPG2s to dedomed XPG3s. It makes no sense to compare a “sliced” G3 to a completely dedomed XPG2. If you want max-to-max comparison, then they should use the LED in its maximum intensity form (at maximum output power), not guesswork of theoretical gains it could have in other scenarios.

I like bright lights, and I cannot lie.

luminarium iaculator
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MEM,

Can you report in this or any other thread throw or lux values of de domed XP-G3 emitter in direct comparison with old XP-G2 S4 2B…? I say old type and that is the key… You can’t compare them with new production G2’s cause although they share same name they ain’t same emitters. Since you are the only person who knows how to de dome it it would be much appreciated in community.

What I know (and probably Djozz you and other guys here) that with “slicing the led method” vs “de dome method” difference can be very little from 5-20% depending on how much silicone did you sliced…

So If Djozz got 200kcd with sliced XP-G3 in well known B158 host (and it really looks like good slice to me):

and he make that test in direct comparison with old type de domed xp-g2 s4 2b that gives 320 kcd that should tell a lot, cause even your properly de domed G3 if we assume that it will have maximum gain of 20% over Djozz sliced one it will still not beat old XP-G2 S4 2B. It will have about 240 kcd in same host with more current sag in dd light. So nicer tint? OK I respect nicer tint but I always choose better performing emitter.

Don’t forgot you claimed that new production process XP-G2 is good and that you can’t spot differences between new and old type? Although imho you are terribly wrong on that and I(and lot of other guys from that thread) have more than one arguments for that(and still waiting for your reply in that thread).

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MEM wrote:
luminarium iaculator wrote:
DavidEF wrote:
djozz wrote:
If the led can be succesfully dedomed after all (or if a HI version becomes available) it will be the top thrower led but with dome it has the competition of the XP-L Hi that is (at twice the price!) still the better performer.
MEM wrote:
These things are absolutely amazing when fully dedomed. I put one in a reflector light last night, and the lumens looked almost identical to the XPL next to it, but with a pure white hotspot 2/3 the size. I honestly would not trade the dedomed tint for anything I have seen yet dedomed. But 7-8 amps at max output? Holy…crap. YES! :Party:

So, de-domed properly, these should out-throw the old style XP-G2 S4 2B. Is that what you guys are saying? I’ve got a couple of the XP-G3 from the VOB group buy from Cutter. I would really like to know how to de-dome one of these. I’ve never had a XP-G2 S4 2B light. I’d really like to see what it’s like. Innocent

I think they are saying that XP-G3 emitter will out throw classic XP-G2 but only if we leave dome on.
And since 80% of us here do de doming, and expecting better performance with newer types of emitters it seems such performance upgrade will not happen with G3.

Wait until someone confirms kcd numbers in well known hosts. I know I would not be impressed with anything that will throw less than old production XP-G2 S4 2B de domed no matter how nice tint is.

Djozz sliced XP-G3 and did put it in well known and consistent performance aspheric host(B158) and results are really not good.

So when it will be pure clean de dome only 10-20% gain could be achieved(in my experience) and not even that will be enough to dethrone old de domed xpg2s42b

Djozz wrote:
How about dedoming this led that is build quite different than the XP-G2 ? Some first attempts by other BLF-members at hot dedoming or in gas were not promising. My own (limited skills !) first attempt at a sliced dome produced a working led but the throw was disappointing. See here. So for now, the ‘king of throw’ is still the ‘old type’ XP-G2 S4 2B, which unfortunately is not available anymore. http://budgetlightforum.com/comment/950071#comment-950071

Why would you say that we are saying “with the dome on”, when I’m talking about a domeless LED? Once again you’re modifying what has been stated by others. Silly

A good experiment is not necessarily putting the LED in a host you are particularly fond of and getting one throw measurement from a sliced-dome LED. To be fair, a sliced LED is going to vary person to person, method to method, slice to slice.

A proper experiment would be using any host, with a “control LED” installed at the start. Then, other LEDs would be placed into the same host, directly comparing dedomed XPG2s to dedomed XPG3s. It makes no sense to compare a “sliced” G3 to a completely dedomed XPG2. If you want max-to-max comparison, then they should use the LED in its maximum intensity form (at maximum output power), not guesswork of theoretical gains it could have in other scenarios.

Agreed. Removing all the variables would be beneficial, a head to head as it were.

luminarium iaculator wrote:
MEM,

Can you report in this or any other thread throw or lux values of de domed XP-G3 emitter in direct comparison with old XP-G2 S4 2B…? I say old type and that is the key… You can’t compare them with new production G2’s cause although they share same name they ain’t same emitters. Since you are the only person who knows how to de dome it it would be much appreciated in community.

What I know (and probably Djozz you and other guys here) that with “slicing the led method” vs “de dome method” difference can be very little from 5-20% depending on how much silicone did you sliced…

So If Djozz got 200kcd with sliced XP-G3 in well known B158 host (and it really looks like good slice to me):

and he make that test in direct comparison with old type de domed xp-g2 s4 2b that gives 320 kcd that should tell a lot, cause even your properly de domed G3 if we assume that it will have maximum gain of 20% over Djozz sliced one it will still not beat old XP-G2 S4 2B. It will have about 240 kcd in same host with more current sag in dd light. So nicer tint? OK I respect nicer tint but I always choose better performing emitter.

Don’t forgot you claimed that new production process XP-G2 is good and that you can’t spot differences between new and old type? Although imho you are terribly wrong on that and I(and lot of other guys from that thread) have more than one arguments for that(and still waiting for your reply in that thread).

That’s a strange way to ask someone to reveal a proprietary process or trade secret IMO

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We do not force MEM to reveal his secrets of dedoming, but an actual throw comparison with some real numbers would definitely bring some light into the whole discussion. And since he is obviously the only one who has succesfully dedomed an xp-g3, his input would be appreciated

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I just dunked one into a gasoline, wish me luck (Stuff that I use takes 24-36 hrs to do the job and even after that time the dome will not fall off by itself but if I budge it a bit it will leave nice and clean LED die, at least with XM-L2/XP-G2)…

 

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johny723 wrote:
We do not force MEM to reveal his secrets of dedoming, but an actual throw comparison with some real numbers would definitely bring some light into the whole discussion. And since he is obviously the only one who has succesfully dedomed an xp-g3, his input would be appreciated

I wasn’t meaning to insinuate asking was wrong, it was just a strange way to posit the request, but again, that’s just my opinion.

It’s obvious that both MEM and djozz have a firm grasp of the behavior of LED’s and the physics involved, so with the limited data points we have at this time its probably a little premature to make sweeping assumptions one way or another. A test of two emitters, both prepped the same way, used in the same host with the same parameters would be really beneficial in determining if the new XP-G3 is going to perform as well as the older XP-G2.

Texlite
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Sirius9 wrote:
I just dunked one into a gasoline, wish me luck (Stuff that I use takes 24-36 hrs to do the job and even after that time the dome will not fall off by itself but if I budge it a bit it will leave nice and clean LED die, at least with XM-L2/XP-G2)…

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djozz - Excellent work, once again! Love it!! Also, lot of things look'n good for the XP-G3. De-doming is still yet to be determined, but doesn't look promising for us laymen modders.

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Instead of boiling gas to dedome faster, one could simply put it in the fridge to slow it down and let the dome swell slowly…?

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Maybe diluting the gas would be a better idea than putting it in the fridge, if only there was a BLF MEMber who could tell us the ratios Wink

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Texlite,

You just become MEM’s lawyer. Cheers guys Beer

I did not ask him to reveal de doming secret but to reveal results in XP-G3 vs OLD XP-G2 S4 2B de domed battle. Is this also a secret? Don’t make me laugh Smile

Djozz already did such test(only with sliced XP-G3) with B158 host and he got about 50% lower performance than with de domed old type xp-g2 s4 2b.

Well known variables are that de domed vs sliced emitter should have maximum 20% better performance over sliced so properly de domed G3 will still not be able to reach OLD xp-g2 s4 2b. He could reach and have better performance than new production s4 2b but it will never reach old S4 2B. Learn difference between new and old production process xp-g2-s4 2b emitters(Gaston01, other guys and myself learned that on a hard way).

Real variables would be :
- de domed g3 v de domed OLD production type XP-G2 S4 2B(cause that emitter was king of throw until Cree messed it with new production process XP-G2 S4 2B)
- same host
- same driver
- same battery
- same lux meter(and it does not have to be super accurate to tell % difference between them)

Djozz did all that with B158 host only with sliced G3 and not de domed one. Add max 20% gain on de domed one and it will still not reach it.

I would really like that G3 or any other new emitter could have same or better throwing potential than old production XP-G2 S4 2B emitter and I am among the first one that would buy larger quantities of it.

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Thanks for the effor Djozz, Appreciated.

Quote:
…If the led can be succesfully dedomed after all (or if a HI version becomes available) it will be the top thrower led but with dome it has the competition of the XP-L Hi…

I still need to see (or experience) this to believe it… I believe the ‘old’ XP-G2 S4s are still the Throw King, by far.

PS: I’m also worried about the beam profile of the XP-G3s. To me, it does not look promising. And, the other caveat, as we all know, to have this LED properly dedomed, we’ll have to send them to MEM for some ‘special’ attention. Yep MEM, you’re probably smiling while reading this… Wink

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luminarium iaculator wrote:
Texlite,

You just become MEM’s lawyer. Cheers guys Beer

I did not ask him to reveal de doming secret but to reveal results in XP-G3 vs OLD XP-G2 S4 2B de domed battle. Is this also a secret? Don’t make me laugh Smile

Djozz already did such test(only with sliced XP-G3) with B158 host and he got about 50% lower performance than with de domed old type xp-g2 s4 2b.

Well known variables are that de domed vs sliced emitter should have maximum 20% better performance over sliced so properly de domed G3 will still not be able to reach OLD xp-g2 s4 2b. He could reach and have better performance than new production s4 2b but it will never reach old S4 2B. Learn difference between new and old production process xp-g2-s4 2b emitters(Gaston01, other guys and myself learned that on a hard way).

Real variables would be :
- de domed g3 v de domed OLD production type XP-G2 S4 2B(cause that emitter was king of throw until Cree messed it with new production process XP-G2 S4 2B)
- same host
- same driver
- same battery
- same lux meter(and it does not have to be super accurate to tell % difference between them)

Djozz did all that with B158 host only with sliced G3 and not de domed one. Add max 20% gain on de domed one and it will still not reach it.

I would really like that G3 or any other new emitter could have same or better throwing potential than old production XP-G2 S4 2B emitter and I am among the first one that would buy larger quantities of it.

+1 BLF is becoming a Secretive Endeavor… Secrects, Secrets, Sectrets… Beer

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A thought…

I’m just combining some information I gathered from being here for a while, I do not know the exact physics behind it (I’m a biologist, in led physics just a BLF-amateur, i.e. DrJones knows better than me what happens to photons).

*The Cree leds used to have a very smooth phosfor layer and showed a lot of tint shift and gained a lot of illuminance upon dedoming
*I have had Luxeon Q leds, Oslon Square leds, Nichia leds that all have rougher phosfor layers. I dedomed or sliced them all and the illuminance never became anything impressive. The tint shift was also less (qualitative observation).
*The latest XP-G2 and XP-G3 have a rough phosfor layer and thusfar the throw after dedoming them seems less than impressive.

The source of improved illuminance upon dedoming (following DrJones’ explanation from back in 2012) is that after passing the phosfor layer, remaining blue photons that are leaving the phosfor layer at high angles are reflected back into the die and have another chance of being absorbed by the phosfor and then emitted at increased wavelength (and thus luxvalue) and at a perhaps lower angle that will escape the die, thus adding to the illuminance and causing a tint shift away from blue.

What if the outer edge of rougher phosfor without silicon dome, that has less surface area parallel to the die surface than a smooth layer of phosfor (this is entirely my own assumption), shows much less internal reflection in the first place, so even without dome the light at high angle can escape anyway? Then less photons are ‘recycled’ (is this word also patented by Wavien? Wink ), and illuminance and tint shift are less increased. So less throw.

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djozz wrote:
A thought…

I’m just combining some information I gathered from being here for a while, I do not know the exact physics behind it (I’m a biologist, in led physics just a BLF-amateur, i.e. DrJones knows better than me what happens to photons).

*The Cree leds used to have a very smooth phosfor layer and showed a lot of tint shift and gained a lot of illuminance upon dedoming
*I have had Luxeon Q leds, Oslon Square leds, Nichia leds that all have rougher phosfor layers. I dedomed or sliced them all and the illuminance never became anything impressive. The tint shift was also less (qualitative observation).
*The latest XP-G2 and XP-G3 have a rough phosfor layer and thusfar the throw after dedoming them seems less than impressive.

The source of improved illuminance upon dedoming (following DrJones’ explanation from back in 2012) is that after passing the phosfor layer, remaining blue photons that are leaving the phosfor layer at high angles are reflected back into the die and have another chance of being absorbed by the phosfor and then emitted at increased wavelength (and thus luxvalue) and at a perhaps lower angle that will escape the die, thus adding to the illuminance and causing a tint shift away from blue.

What if the outer edge of rougher phosfor without silicon dome, that has less surface area parallel to the die surface than a smooth layer of phosfor (this is entirely my own assumption), shows much less internal reflection in the first place, so even without dome the light at high angle can escape anyway? Then less photons are ‘recycled’ (is this word also patented by Wavien? Wink ), and illuminance and tint shift are less increased. So less throw.

That’s certainly a possibility I suppose. The thickness of the phosphor on the edges could also play a role as well, but that’s only a guess on my part.

Either way, unfortunately, I guess there’s not much we as end users can do about it one way or another.

Thanks again for taking the time to do the testing.

-Michael

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viperbart wrote:
Instead of boiling gas to dedome faster, one could simply put it in the fridge to slow it down and let the dome swell slowly…?

My dome would swell quite rapidly (due to repeated hits from a 2×4) once my wife discovered the jar containing gasoline I simply put in the fridge.

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ImA4Wheelr wrote:
viperbart wrote:
Instead of boiling gas to dedome faster, one could simply put it in the fridge to slow it down and let the dome swell slowly…?

My dome would swell quite rapidly (due to repeated hits from a 2×4) once my wife discovered the jar containing gasoline I simply put in the fridge.

Lol.

Ice packs and chilled water in a lunch cooler outside?

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Sirius9 wrote:
I just dunked one into a gasoline, wish me luck
well, 2 days after, this is the result: (Dome was swollen and separated at the edges of the emitter and, as you can see, some of the phosphor left on the dome, also some of the silicone from the dome left stuck on the entire die, usually, after this time die is left nice and clean with XP-G2 or XM-L2, I just have to clean silicone around the die and it's nice and slick but with XP-G3 .... well you can see, I would call it a fail and I have siriuos doubts that "diluted" this or that actuall works as stated by MEM.)

XPG3

 

I did few quick tests, just connected some batteries directly to this leds and observed current draw

Bettery dedomed XP-G3 dedomed XP-L
Panasonic NCR18650PF - 4.04V 5.60A 2.97A

Samsung ICR18650-26FU

laptop pull in good shape - 4.13V

4.44A 2.78A

generic battery pack 3P

configuration - 4.0V

unbranded cells

6.30A 3.26A

 

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djozz quotes, "it came with chinese lettering that is chinese to me".

                      "My man mousehole needs one too"

old4570 said "I'm not an expert , so don't suffer from any such technical restrictions".

Old-Lumens. Highly admired and cherished member of Budget Light Forum. 11.5.2011 - 20.12.16. RIP.

 

ImA4Wheelr
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viperbart wrote:
ImA4Wheelr wrote:
viperbart wrote:
Instead of boiling gas to dedome faster, one could simply put it in the fridge to slow it down and let the dome swell slowly…?

My dome would swell quite rapidly (due to repeated hits from a 2×4) once my wife discovered the jar containing gasoline I simply put in the fridge.

Lol.

Ice packs and chilled water in a lunch cooler outside?

You, my friend, have a knack for problem solving. Marital bless, and my somewhat dimmish dome, shall be maintained if I ever try a slow dedome. Smile

Texlite
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Sirius9 wrote:

Sirius9 wrote:
I just dunked one into a gasoline, wish me luck
well, 2 days after, this is the result: (Dome was swollen and separated at the edges of the emitter and, as you can see, some of the phosphor left on the dome, also some of the silicone from the dome left stuck on the entire die, usually, after this time die is left nice and clean with XP-G2 or XM-L2, I just have to clean silicone around the die and it’s nice and slick but with XP-G3 …. well you can see, I would call it a fail and I have siriuos doubts that “diluted” this or that actuall works as stated by MEM.)

XPG3


 


I did few quick tests, just connected some batteries directly to this leds and observed current draw




















Bettery dedomed XP-G3 dedomed XP-L
Panasonic NCR18650PF – 4.04V 5.60A 2.97A

Samsung ICR18650-26FU


laptop pull in good shape – 4.13V


4.44A 2.78A

generic battery pack 3P


configuration – 4.0V


unbranded cells

6.30A 3.26A

Well, I wouldn’t call it a complete failure, the phosphor is still intact, and it does light, so partial failure at worst.

I’d call it Success with complications.

Whats the beam pattern like? Did the tint shift significantly?

DavidEF
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Sirius, you do know that the square in the middle is the die, right? That phosphor around the edge doesn’t even matter. You can probably just scrape it back to get straight edges again and it will be fine.

The Cycle of Goodness: “No one prospers without rendering benefit to others”
- The YKK Philosophy

Sirius9
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DavidEF wrote:
Sirius, you do know that the square in the middle is the die, right? That phosphor around the edge doesn’t even matter. You can probably just scrape it back to get straight edges again and it will be fine.

Of course I know that and I thought to scrape it off but I wanted to show to BLF members first how it looks after slow chemical dedome without beauty treatment Smile
Also, you can probably notice that top and left edge of the emitter die is missing some phosphor, that phosphor was stuck on the silicone dome and this was not caused by my forcing the dome but was already like that when I pullet the emitter from the gasoline, swelling of the dome caused that.

 

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