Led coatings

Rocket Soul said:

Or perhaps covering the less in plastic while burning right?

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I'd suggest that any type of conformal coating is going to give your LEDs better protection from SO2 than no coating at all. Plus you could just spray the LEDs down after application, as they would be waterproof.

There’s also the Urethan 71 from
Kontakt Chemie .A PU cc without
UV tracer.Still it’ s a bit yellowish in appearance as it is stated at the product’s TDS.







EDIT: For my next DIY LED grow light
project I’ve ordered a PU potting compound
from Electrolube ( UR 5634 ) .

So first acrylic was presented as surely the best coating and now it's something else. At least the understanding that silicone is at the base seems to have gotten through.

As the answer to the original question I would say, wait till someone actually knows what they are talking about replies. Since for now it's clear we only get some google results being copy pasted here.

If you actually need any protective coating at all. How many people have seen issues with their leds? I've used some of mine for 6 years now and they still look perfect. All I did was clean them with IPA now and then.

Rocket Soul said:

...sourcing leds thru china ...

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I’ve almost forgotten this ..
Back then ,when growing with white LEDs was considered madness,
a waste of money and light ...
When red & blue LED grow lights were
the mainstream.
Uh-oh ...
Luckily , few of us we had a very different opinion .

wietefras said:

So first acrylic was presented as surely the best coating and now it's something else. At least the understanding that silicone is at the base seems to have gotten through.

As the answer to the original question I would say, wait till someone actually knows what they are talking about replies. Since for now it's clear we only get some google results being copy pasted here.

If you actually need any protective coating at all. How many people have seen issues with their leds? I've used some of mine for 6 years now and they still look perfect. All I did was clean them with IPA now and then.

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With a small difference there ...
Acrylic was an option for conformal coating ...
Potting compound is something else.
But both serve the same purpose ,of course.

By all means ,you ‘ve every right to do as you wish with your LEDs.I prefer mine to be protected as much as possible .And since you’asked ,yes I’ve seen damaged and tarnished LEDs.We all live in different places you see .And actually ,air pollution is an ongoing issue where I live ,since the place is an industrial area.

That's not a difference. Acrylic was proposed as a coating on top of the LES until it was clear that that doesn't actually work on most leds due to the silicone used. I point this out as evidence that people should take the "definitive answers" in this thread as loose suggestions rather than proven alternatives.

Lol, if the air quality is that bad that your leds get damaged than you have a completely different issue. Not sure which planet that is though.

wietefras said:

Lol, if the air quality is that bad that your leds get damaged than you have a completely different issue. Not sure which planet that is though.

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It’s the same planet that you live onto.
And if you are totally unaware that in certain industrial areas on this planet people living there wore masks long before COVID-19 and that many times the visibility due to air pollution drops down to a radius of few hundred meters, then you must be a newcomer to planet Earth .
I’ve to replace my LED lights of my house every 3-4 years or so,because they get so dim that they output no more than a candle .
The city Im living has one of the highest rates of lung cancer and other respiratory related diseases in the whole EU ..But ,how should you know about all these ?

BTW,welcome to planet Earth .

SDS_GR said:

It’s the same planet that you live onto.
And if you are totally unaware that in certain industrial areas on this planet people living there wore masks long before COVID-19 and that many times the visibility due to air pollution drops down to a radius of few hundred meters, then you must be a newcomer to planet Earth .
I’ve to replace my LED lights of my house every 3-4 years or so,because they get so dim that they output no more than a candle .
The city Im living has one of the highest rates of lung cancer and other respiratory related diseases in the whole EU ..But ,how should you know about all these ?

BTW,welcome to planet Earth .

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Man, thats a bit sad. I hope you can find a new place, especially with new family. It sounds real serious.

Rocket Soul said:

Man, thats a bit sad. I hope you can find a new place, especially with new family. It sounds real serious.

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Unfortunately ,moving elsewhere is not that easy .The “ job opportunities“ life chapter here in Greece tends to become a short,bitter joke.
But thank you anyway.

At the suburbs of the city I’m living is cited a vast industrial area ,
with two steel factories ,a plastic pipes factory ,several mining facilities
(perlite,cement,etc) ,an aluminium factory ,few agrochemical factories and few other facilities .Some of them burn RDF ( aka garbage ) in order to cover their energy needs.
Add to the equation the mountains surrounding the city ,acting as a natural barrier to the wind and there you have a stagnant,yellowish-brown, thick polluted air that smells burned plastic .
Quite often during winter ,especially at nights,when almost every home ,( in a city of few million inhabitants ) burns wood for heating (diesel & gas are long forgotten commodities of the glorious past ... ) it’s impossible to go out for a short walk.The burning sensation on the eyes and the suffocating blend of smog with smoke ,make a simple walk to the closest 7-11 to feel like a trip in hell.
Blessed the ones that are completely unaware of all these ...

SDS_GR said:

https://d3i71xaburhd42.cloudfront.net/fd4f2f3ad41614c5a090f323499736b0cabf8f74/2-Figure1-1.png

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Ive been to athens in summer, didnt stay long enough to even go to the akropolis. Barcelona is them same, locked into mountains. But weve been having better air due to all the quarantine.

SDS_GR said:

It’s the same planet that you live onto.
And if you are totally unaware that in certain industrial areas on this planet people living there wore masks long before COVID-19 and that many times the visibility due to air pollution drops down to a radius of few hundred meters, then you must be a newcomer to planet Earth .
I’ve to replace my LED lights of my house every 3-4 years or so,because they get so dim that they output no more than a candle .
The city Im living has one of the highest rates of lung cancer and other respiratory related diseases in the whole EU ..

But ,how should you know about all these ?

BTW,welcome to planet Earth .

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Nice story bro. Dust doesn't damage the LES though and corrosive gasses are not stopped by a face mask. Normal led lights are covered by some form of cover already. It just does not add up.

So I'm really not buying this. Not sure how it's relevant either, but good for you that you started looking into adding a coating to prevent this "problem".

Either way, the point is that I see "best working solutions" presented while you just yesterday started investigating this coating issue. OK, I guess saying that we can cue the stories about how you have been doing this for years already, but then I would point out that you already stated that you never used any of this on leds.

I disdain to reply anymore.
Have a nice day,sir.

When an ordinary rubber band can cause damage ...


(...)
Besides from natural sources, atmospheric H2S originates from livestock production and industrial processes, such as the combustion of biomass and fossil fuels(...)
Source: https://www.frontiersin.org/articles/10.3389/fpls.2019.00743/full

burning wood and RDF = burning biomass

.... But still I’m sure that a knife or two in the drawer will always resist sharpening ...
And then the “ ignore“ function works wonders !

wietefras said:

So first acrylic was presented as surely the best coating and now it's something else. At least the understanding that silicone is at the base seems to have gotten through.

As the answer to the original question I would say, wait till someone actually knows what they are talking about replies. Since for now it's clear we only get some google results being copy pasted here.

If you actually need any protective coating at all. How many people have seen issues with their leds? I've used some of mine for 6 years now and they still look perfect. All I did was clean them with IPA now and then.

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Your LEDs "look perfect" – I suppose you have measured their light output with a sphere or gonio to prove how "perfect" they are, right? You have no way to prove what you say unless you have some reliable light testing equipment to compare your LEDs before and after.

Furthermore, there are many cases in indoor horticulture where you might wish to protect your exposed LEDs and PCB from moisture or direct water contact (misting, sprinklers etc), so it is an entirely valid discussion.

Lastly, how do you know the people commenting here have no experience with conformal coating? You don't. And you are wrong.

wietefras said:

Nice story bro. Dust doesn't damage the LES though and corrosive gasses are not stopped by a face mask. Normal led lights are covered by some form of cover already. It just does not add up.

So I'm really not buying this. Not sure how it's relevant either, but good for you that you started looking into adding a coating to prevent this "problem".

Either way, the point is that I see "best working solutions" presented while you just yesterday started investigating this coating issue. OK, I guess saying that we can cue the stories about how you have been doing this for years already, but then I would point out that you already stated that you never used any of this on leds.

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Carbon-filter face masks are designed to capture and render corrosive gases inert. So again, do not apply your own narrow thinking to someone else's situation – because you simply do not know.

Indeed, if you weren't such a jerk to everyone you interact with you might actually learn something. You certainly don't know it all – despite trying to convince us all otherwise – because your attitude is an impediment to learning.

Just arrived !







@Prawn Connery
I need your help ,please.

I will use this PU potting compound for covering the LED devices of 8x
Photo Boost strips from PLC.
Each strip has 96x LM301 having a height of approx 0.75 mm plus the added thickness of the solder and
4x XP-G3 which have a height of
~ 2.3mm ,plus the solder thickness.
All of them placed in a single straight line.

Since the mixed resin has a bit more viscosity than SAE 40 motor oil
(~1000 mPa s),
some kind of restraining is needed
around the straight line that the LEDs form ,so that the liquid resin will stay put and won’t overflow on the mcpcb ,while at the same time will encapsulate completely the LEDs.

After some brain-squeezing I’ve decided to use a 2 mm thick silicone Nano tape -cut in fine strips- and stick it on the mcpcb ,surrounding the line of LEDs.That will serve as a “mold”-sort of -and hopefully will keep the resin within it’s slim rectangular shape ,until it cures .
Afterwards ,the silicone nano tape strips will be removed ,since PU does not really adhere to silicone .


Of course ,before all that is done ,a thorough degreasing of the Photo Boost LED strips with IPA ,is rather obligatory.

Any advice ,suggestion and/or tips
are more than welcome .

SDS_GR said:

Just arrived !

UR5634 Optically Clear Polyurethane LED Potting Compound - Electrolube

Optically clear polyurethane LED potting compound formulated to protect LEDs from the environment. UV and mould resistant, suitable for indoor or outdoor.

electrolube.com

@Prawn Connery
I need your help ,please.

I will use this PU potting compound for covering the LED devices of 8x
Photo Boost strips from PLC.
Each strip has 96x LM301 having a height of approx 0.75 mm plus the added thickness of the solder and
4x XP-G3 which have a height of
~ 2.3mm ,plus the solder thickness.
All of them placed in a single straight line.

Since the mixed resin has a bit more viscosity than SAE 40 motor oil
(~1000 mPa s),
some kind of restraining is needed
around the straight line that the LEDs form ,so that the liquid resin will stay put and won’t overflow on the mcpcb ,while at the same time will encapsulate completely the LEDs.

After some brain-squeezing I’ve decided to use a 2 mm thick silicone Nano tape -cut in fine strips- and stick it on the mcpcb ,surrounding the line of LEDs.That will serve as a “mold”-sort of -and hopefully will keep the resin within it’s slim rectangular shape ,until it cures .
Afterwards ,the silicone nano tape strips will be removed ,since PU does not really adhere to silicone .

Of course ,before all that is done ,a thorough degreasing of the Photo Boost LED strips with IPA ,is rather obligatory.

Any advice ,suggestion and/or tips
are more than welcome .

Click to expand...

This will be interesting. We looked at this same urethane conformal coating early on but decided not to trial it for the points you've raised. Ideally you need a dam around the strips to set the potting resin so that it is just high enough to a level off on top of the LEDs to form a thin coat. Having different height LEDs is the problem. If you encapsulate the 3535s, you will have quite a thick resin over the 3030s. If you pour to the height of the 3030s, you will not entirely encapsulate the 3535s. If you try to do them all individually or in 3030/3535 rows it's a lot of work. However, you could fill to 3030 height and then brush the tops of the 3535s and hope the resin is viscous enough to form a thin film over the lens. You could wait for it to thicken a little before trying it. I would try that first before trying to build lots of individual dams. You can always repot the 3535s individually if the brush doesn't leave a thin film.

For a dam you could try one or two layers of masking tape or plasticine, and for a release agent we like to use neutral shoe polish – Kiwi is a good brand. You can melt it with a flame and smear it wherever you need it.

Thank you very much ,sir .

I considered plasticine as an option and ruled it out ,as I thought that the resin solvents might dissolve the mineral oil of plasticine,thus contaminating the resin ...

Cool tip with the neutral color shoe polish !
I can find PVA locally for really cheap.
Isn’t that substance used as a release agent when casting resins ?

Another issue with that resin that kinda
stresses me ,is the quite short available time to work with it ( 15 min @ 20C ) ,
before it starts to gel ...
I will have to pour it in 8x 2ft strips & make sure it covered properly the LEDs within 15 minutes .
Meaning that I will have available less than two minutes to work with each board !

The issue with the different LED heights really gives me a hard time to find a solution for...
I was thinking to pour the resin ,until it covers the height of LM301 LEDs first and then go back again -after potting all eight strips-and pour some resin slowly on top of the XP-G3 ones ,while hoping that the viscosity of the resin will be adequate enough to keep it on top of the previously poured layer .

I ‘ve to plan everything really carefully.


Edit: It seems that up to 2 mm thick
coat ,light loss and color shift are kept at minimal levels .Going for a thicker layer will have a more pronounced impact on both .

Image source:

So it's 3 years later, any conclusions on which conformal coating is best? HLG mentions in podcast that silicone is not the way to go: 01:03:00

He doesn't mention which alternatives he says is better and only reduce efficiency by 1/10 of 1%? He only says silicone yellows and produces mold..? Anyways, wonder what coating he is talking about that the Chinese version of OSHA doesn't like?

I'd like to get my hands on some of that coating. Anyone know what it is??

KitnerPush said:

So it's 3 years later, any conclusions on which conformal coating is best? HLG mentions in podcast that silicone is not the way to go:

01:03:00

He doesn't mention which alternatives he says is better and only reduce efficiency by 1/10 of 1%? He only says silicone yellows and produces mold..? Anyways, wonder what coating he is talking about that the Chinese version of OSHA doesn't like?

I'd like to get my hands on some of that coating. Anyone know what it is??

Click to expand...

We use a modified silicon conformal coating that is not made in China. It sprays on very thin, sticks to silicon lens LEDS, doesn't grow mould or yellow, and we lose way less than 1% of light (tested on a goniometer). We tried a few different coatings before we found the one that worked best. I would like to tell you what we use, but no-one else in the industry uses it and it is custom made for us. It is by far the best thing we have found. One of the other issues of conformal coating no-one talks about is colour shift. We had to do a lot of light testing to find a coating that did not absorb or fluoresce the UVA we use. We have seen what happens to uncoated boards after 2-3 years of high humidity exposure and the problem is not sulfurisation, but corrosion of the PCB, namely the copper trace.

We coat all our boards now, and of course we don't make them in China so we don't care what they can and can't use over there – we can use whatever we like.

Prawn Connery said:

We use a modified silicon conformal coating that is not made in China. It sprays on very thin, sticks to silicon lens LEDS, doesn't grow mould or yellow, and we lose way less than 1% of light (tested on a goniometer). We tried a few different coatings before we found the one that worked best. I would like to tell you what we use, but no-one else in the industry uses it and it is custom made for us. It is by far the best thing we have found. One of the other issues of conformal coating no-one talks about is colour shift. We had to do a lot of light testing to find a coating that did not absorb or fluoresce the UVA we use. We have seen what happens to uncoated boards after 2-3 years of high humidity exposure and the problem is not sulfurisation, but corrosion of the PCB, namely the copper trace.

We coat all our boards now, and of course we don't make them in China so we don't care what they can and can't use over there – we can use whatever we like.

View attachment 5336284

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Well shit son, where can I get me some?