A Perfect Dedome?

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Dusty
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djozz wrote:
To me it is a bit of a BLF-myth that the used chemical for dedoming has any effect on the resulting tint.

Thank you djozz for saying that. You are right. I don’t know the exact bin of my first few. Knowing, what I have done since, I am much happier with the outcome. Still, even though I’m color challenged, I see a pretty big difference between a domed, and de-domed led. Everyone says they get warmer. I don’t know what that means. All I see is blue, green, yellow, orange , and red Smile .

Bug

Lightbringer
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djozz wrote:
Are you guys sure that the solvent made your leds turn green and not the tint of the led you started with? To me it is a bit of a BLF-myth that the used chemical for dedoming has any effect on the resulting tint.

That’s what I’m thinking. Dunno anything that’d eat certain “types”(??) of phosphor, eg, those that emit red and yellow (leaving green), yet leave alone other “types”.

Unless different phosphors are put down in layers vs as a mix, and a sloppy dedome takes off a bit of the topmost layer. But you’d see that on the blob of silicone that comes off, I’d imagine.

Don’t think phosphor would oxidise, form a hydrate, etc. Especially if nobody notices any green-shift of a long-dedomed LED that’s been in a flashlight for years.

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Lightbringer
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Sledgestone wrote:
As I’m still very green at dedoming…

Ha!

 

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khas
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Some of the LED’s I have de-domed had a bit of green on the very low modes. I have been experimenting with heating up the LED after the de-doming this actually seems to reduce the green significantly. I don’t have any specific method yet it’s more trial and error at the moment. I heat the LED on the MCPCB as you would with a re-flow, I find this eliminates most of the green on the low modes, so far I have done four (two XM-L2 & two SST-40) and they turned out great. I still need to do some more LED’s to see if I can replicate the results or if I just got lucky.

Most of the LED’s I have de-domed until now was of unknown tint but the difference between a C or a D tint must have a impact on the de-domed tint. One of the best tints so far was a XM-L2 3D came out really nice if you like the warmer tints.

EDIT :

I have ordered some XM-L2 U3 0D and 0C to see what difference if any the tint makes.

EasyB
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Here are some measurements on the tint shift from dedoming: http://budgetlightforum.com/node/32255

I think the majority of the tint shift is a result of the dedoming itself rather than the method. See here for some discussion: http://budgetlightforum.com/node/15818

Sledgestone
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EasyB wrote:
Here are some measurements on the tint shift from dedoming: http://budgetlightforum.com/node/32255

I think the majority of the tint shift is a result of the dedoming itself rather than the method. See here for some discussion: http://budgetlightforum.com/node/15818

I’ve read through this before and I’m bound to agree with it. But then I read that Mitko and another member here mix chemicals so that no tint shift occurs. Then again it’s impossible to know if it’s true or not when they are reluctant to share their method..

LightRider
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Sledgestone wrote:
EasyB wrote:
Here are some measurements on the tint shift from dedoming: http://budgetlightforum.com/node/32255

I think the majority of the tint shift is a result of the dedoming itself rather than the method. See here for some discussion: http://budgetlightforum.com/node/15818

I’ve read through this before and I’m bound to agree with it. But then I read that Mitko and another member here mix chemicals so that no tint shift occurs. Then again it’s impossible to know if it’s true or not when they refuse to share their method..

In all fairness, mitko did share his meathod here,

Mitko wrote:
XHP35 with a hot running muxture ot medical beznine, trimethylphosphate, kerosene, and coresiline

At last a 100% nice results, absolutely no tint shift, !a is even better than 3D

Like 22-24% better than Hi version , nearly no lumen loss( like 5-6%)

Sledgestone
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Ah, I forgot about that post. But he never revealed how much he used of each chemical.

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Lightbringer wrote:
18sixfifty wrote:
You can see from the MSDS that it includes Toluene, Acetone, Ethyl Acetate and Methanol.

Fooey. Neither EtOAc nor MeOH does anything to silicone. Personally, I’d stick with straight toluene. Probably cheaper per gallon, too.

Unless someone wants to mix up a witch’s brew of xylene, toluene, MEK, and other HC nasties. Might be mutual “adjuvants” to softening silicone.

It seems that people with the best results are using a mixture of chemicals. I’ve wondered, are the domes pure silicone? Also, I’ve wondered if there might be some kind of glue or other substance to help the silicone adhere to the substrate. I would think silicone would adhere on its own but after dedoming a number of times the silicone seems different where it meets the substrate. I believe that it is just silicone but i through these thoughts out there in case I’m wrong.

Sledgestone
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khas wrote:
Some of the LED’s I have de-domed had a bit of green on the very low modes. I have been experimenting with heating up the LED after the de-doming this actually seems to reduce the green significantly. I don’t have any specific method yet it’s more trial and error at the moment. I heat the LED on the MCPCB as you would with a re-flow, I find this eliminates most of the green on the low modes, so far I have done four (two XM-L2 & two SST-40) and they turned out great. I still need to do some more LED’s to see if I can replicate the results or if I just got lucky.

Most of the LED’s I have de-domed until now was of unknown tint but the difference between a C or a D tint must have a impact on the de-domed tint. One of the best tints so far was a XM-L2 3D came out really nice if you like the warmer tints.

EDIT :

I have ordered some XM-L2 U3 0D and 0C to see what difference if any the tint makes.

How much did you heat the mcpcb? Just enough to melt the solder under the LED or longer than that? And did you use a hot plate or iron?

Lightbringer
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Sledgestone wrote:
EasyB wrote:
Here are some measurements on the tint shift from dedoming: http://budgetlightforum.com/node/32255

I think the majority of the tint shift is a result of the dedoming itself rather than the method. See here for some discussion: http://budgetlightforum.com/node/15818

I’ve read through this before and I’m bound to agree with it. But then I read that Mitko and another member here mix chemicals so that no tint shift occurs. Then again it’s impossible to know if it’s true or not when they are reluctant to share their method..

I got these bottles, hit them with a hammer, and they all break.

This new batch of bottles, I rinse with bleach before hitting them, and most of them stay intact.

That’s kinda the problem, that there’s no redoing the dedome with the same LED. Someone gets an “old” batch of XP-Gs, then a “new” batch of XP-Gs, and claims or actually sees a difference with a different solvent, but there’s no way to know that the LEDs all had the same exact tint (they’re tint bins, don’t forget) beforehand, and then acted differently after dedoming.

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Lightbringer
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Sledgestone wrote:
Ah, I forgot about that post. But he never revealed how much he used of each chemical.

Or as I asked afterward, wotnahell are those chemicals. Spelling counts in chemistry, else things go boom.

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djozz
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I did a new XM-L2 dedome with my ‘nitro-verdünner’, but now left it overnight without heating up (it is summer here so +20 degC even at night). The dome was next to the led the next morning. After drying I just blew the last bits off.

Sledgestone
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I guess that you have a good point there, Lightbringer.

How is the tint Djozz?

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Did any of you ever asked any led manufacturer about this?

Maybe we should ask them to include a “recommended household/industrial list of chemicals to use in hot* bath dome dissolving procedures for high intensity applications”, with notes and remarks, in their datasheets. 

 

Please avoid fully quoting lenghty posts, namely with nested quotes. Trim quotes down to the essential. Helps with neatness and legibility. Thanks.

The human mind, and its programming, is at the forefront of a particular battle of The Light vs evil dark forces. Nearly every human being on this beautiful planet “Earth” has some sort of negative mind programming in its mind. And you better take care of your mind programming, or someone else will in this wicked world.

18sixfifty
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Lightbringer wrote:
Sledgestone wrote:
EasyB wrote:
Here are some measurements on the tint shift from dedoming: http://budgetlightforum.com/node/32255

I think the majority of the tint shift is a result of the dedoming itself rather than the method. See here for some discussion: http://budgetlightforum.com/node/15818

I’ve read through this before and I’m bound to agree with it. But then I read that Mitko and another member here mix chemicals so that no tint shift occurs. Then again it’s impossible to know if it’s true or not when they are reluctant to share their method..

I got these bottles, hit them with a hammer, and they all break.

This new batch of bottles, I rinse with bleach before hitting them, and most of them stay intact.

That’s kinda the problem, that there’s no redoing the dedome with the same LED. Someone gets an “old” batch of XP-Gs, then a “new” batch of XP-Gs, and claims or actually sees a difference with a different solvent, but there’s no way to know that the LEDs all had the same exact tint (they’re tint bins, don’t forget) beforehand, and then acted differently after dedoming.

That could be one of the problems of trying to figure out if how you de-dome matters.

However, consider this. A while back I bought a hundred XP-G2’s from the same supplier of the same bin. I de-domed around 90 of them successfully using the same method and each and every one of them had the same tint once de-domed. I remember them in particular because they came out with a rosy tint after de-doming them and I loved it. I think there is a lot more consistency than you think when it comes to bins, so that it should be possible to find out if different chemicals change the tint or not. Wouldn’t you say that If I had de-domed half of this batch with Gas and got rosy tints and half with nitro and got green that it would in fact be the nitro that is the culprit? Also considering that dozens and dozens of members here have all reported back on their results and have agreed that some Bins are nice after de-doming and others are not, wouldn’t this also suggest that Bins are fairly standard? Different people around the country get the same results from the same bins so that certainly makes it seem that the bins are fairly consistent to me.

I’m a junky, I mod lights so I can sell lights so I can buy more light to mod so I can sell lights to buy more lights to mod.

JaredM
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Here's a list I found in random google search. They seem to be ordered in terms of effectiveness..

 

http://www.clearcoproducts.com/pdf/library/Solubility1.pdf

https://fundrazr.com/osturaband

No affiliation, just a fan.

Lightbringer
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18sixfifty wrote:
However, consider this. A while back I bought a hundred XP-G2’s from the same supplier of the same bin. I de-domed around 90 of them successfully using the same method and each and every one of them had the same tint once de-domed. I remember them in particular because they came out with a rosy tint after de-doming them and I loved it.

Ooh, what bin?

18sixfifty wrote:
I think there is a lot more consistency than you think when it comes to bins, so that it should be possible to find out if different chemicals change the tint or not. Wouldn’t you say that If I had de-domed half of this batch with Gas and got rosy tints and half with nitro and got green that it would in fact be the nitro that is the culprit?

Absolutely. That’s why we need the Scientific Method™.

If someone is going to dedome 100 LEDs, all from the same lot, maybe split them 50/50, gas one and nitro the other. Or whatever solvents you’d use. First spot-check the LEDs before dedoming to see if they hold up as far as being close in CT and tint.

Then compare the results. If one solvent gives a nice color and the other gives a horrid green tint, then we absolutely know that the solvent makes a difference.

18sixfifty wrote:
Also considering that dozens and dozens of members here have all reported back on their results and have agreed that some Bins are nice after de-doming and others are not, wouldn’t this also suggest that Bins are fairly standard? Different people around the country get the same results from the same bins so that certainly makes it seem that the bins are fairly consistent to me.

But some get their LEDs from FT, others from KD, others from MTN, etc.

And an LED could be on the ansi-white chart on the rightmost edge of a 3A, and another on the leftmost edge of a 3D, yet look almost identical, despite different labels of “3A” vs “3D”.

Similarly, a bunch of 1Ds might be alllll over that patch that qualifies a 1D, one close to 1A, the other close to 2A, an other greener one close to a 1C. That’s what I mean about a range of CT/tint within a particular bin.

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Sledgestone
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Good find, Jared! Thumbs Up

JaredM
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That wouldn't be a bad experiment except for someone needing to use so many LEDs and taking so much time. 

I think the simplest test to get a clue in on the question of certain solvents causing a green tint would be to sacrifice one or a few hot dedomed LEDs with a good tint and soak them in the 'bad' solvents like gasoline, then determine if the tint changes upon removal.

https://fundrazr.com/osturaband

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Sledgestone
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I agree, that would be a definite way of telling if it makes a difference to the tint or not.

Now we just need to find someone who’s willing to do it Big Smile

Lightbringer
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JaredM wrote:
That wouldn’t be a bad experiment except for someone needing to use so many LEDs and taking so much time.

Forgot who, but someone here mentioned doing a whole bunch at a time.

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Sledgestone wrote:
How is the tint Djozz?

+1.

 

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

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I have experienced a dedomed XP-E2 shifting to green quite a lot..
But then i remembered i didn’t rinse it with alcohol.
So i put it in the dedoming solution i had (terpentine, benzine, thinner, kerosine, petrol (gas) iirc) and after that rinsed with alcohol (i used bio ethanol).
It turned out better than it was.
But i have no pictures or measurements.

Jerommel
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But shouldn’t we be looking for the best silicone remover?

Sledgestone
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Well, that’s exactly what we’re doing Silly

And right now my best bet is Toulene.

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Sledgestone wrote:
Well, that’s exactly what we’re doing Silly

And right now my best bet is Toulene.


Smile

Thing is, toluene is found in what we call ‘thinner’ here, so why should we look for ‘nitro thinner’ if it’s the toluene we’re looking for?

djozz
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Sledgestone wrote:
I guess that you have a good point there, Lightbringer.

How is the tint Djozz?


I have not checked the tint, but it is a random cool white led from the spares box, the tint is relevant if I would have known the tint that I started with..

Edit: FWIW, I checked tint anyway: pretty good actually, not ugly green, must have been a tint on or under the BBL before the dedome.

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OK so the experiment with the solvent I had on hand didn’t work. Or should I say it was no better than hot gasoline or using acetone. So I broke down and bought some toluene and will try that and report back. I’ve got 50 of the SST-40’s showing up soon to experiment on. I’m making a TR-J20 for a member here and want to make sure that he gets 12 perfect de-domes in there.

On the bin that turned Rosy, that was quite a while back, I bought them on sale for cheap on one of the big aliexpress shopping days. That was back when XP-G2’s had just come out so for that time they were great but they wouldn’t be high bin enough for today, not compared with the S4 2B’s. Still I liked them a lot and wish that more of them would de-dome that color. They actually reminded me a lot of a nichia. The problem with ali-express buys are that you never really know exactly what you are getting. You might get lucky and you might not. So I haven’t bought from them in a long time.

I’m a junky, I mod lights so I can sell lights so I can buy more light to mod so I can sell lights to buy more lights to mod.

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Jerommel wrote:
Sledgestone wrote:
Well, that’s exactly what we’re doing Silly

And right now my best bet is Toulene.


Smile

Thing is, toluene is found in what we call ‘thinner’ here, so why should we look for ‘nitro thinner’ if it’s the toluene we’re looking for?

Mainly because Nitro thinner apart from toulene also contains several other chemicals that removes silicone. And also because there have been reports of very little green tint shift.

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