Freezing LED's

Hey guys,
Had a wacky idea that would involve deliberately freezing an LED,
Would this cause any damage?
Thanks

I guess it depends on How cold a temperature and for how long?

I have tested a few lights in my freezer for up to an hour. I had a thermometer and it was anywhere from 12F to -6F.

Is this going to be a bare LED or is it in a light and actually being used?

LEDs get brighter the colder you make them, have at it. The weak point is firstly the battery; alkalines get iffy at 32F, Li-ions begin to lose capacity at 0F, lithium primaries will hang in there until -40C. At that temperature the lubricant on your flashlight's o-rings will most likely be seized.

So I'm wanting to freeze an LED for the propose of temporarily hardening the silicone dome.
The idea is a bit out there.
I'm wanting to slice ~the top 1/3 of the dome off and then freeze it so I can polish it. I then intend to coat the top in something highly light reflective. The idea is to use the top surface to reflect light back at the phosphor and hopefully act like its own RLT.
I want to see how it compares to a stock led and a sliced led in terms of throw.

LN2 works nicely for that however, it's likely that the dome will crack &/or fall of in the process. Repeated freeze cycles will eventually render the Si into useless dust as well.

You'll probably be fine.
Back in college (70s), when LEDs were pretty novel, we had to do a lab experiment to calculate something like electron energy levels, and the procedure was to light up the red 5mm LED and dip it into a flask of liquid nitrogen and see when the light died. When you took it out and warmed it back up, it worked fine.

I won't be using liquid nitrogen, just my household freezer. I just want it to be firmer so it doesn't shift around too much when I use the dremel to polish it.

The temperature shouldn't be an issue, but there might be a couple related matters worth keeping in mind.

LED's, being very small, will warm up very quickly once out of the freezer. Keeping it cold may be challenging, but being in contact with a large heat sink that is also frozen would help.

If it's not soldered in place, there may be some humidity concerns. Here's what one datasheet says:

Moisture Sensitivity
Cree recommends keeping XLamp LEDs in the provided, resealable moisture-barrier packaging (MBP) until immediately prior to soldering. Unopened MBPs that contain XLamp LEDs do not need special storage for moisture sensitivity.

Once the MBP is opened, XLamp XHP35 LEDs may be stored as MSL 1 per JEDEC J-STD-033, meaning they have unlimited floor life in conditions of ≤ 30 ºC/85% relative humidity (RH). Regardless of the storage condition, Cree recommends sealing any unsoldered LEDs in the original MBP.

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The referenced JEDEC standard indicates this is apparently due to the potential for moisture to soak into the chip, then expand when heated for soldering, potentially damaging the chip. Cree says theirs are ok up to at least 85% humidity, but I don't know if condensation due to the cold could be a concern in your case. If so, I think a couple hours in an oven at low temperature or a couple days in a ziplock along with a bag of desiccant will probably help ensure no problems.

Cannot speak for all lights but some don't mind being frozen

I second that- when there have been questions about if a light is as waterproof as advertised, I have multiple times frozen them like bykfixer' s examples. Last time was the Surefire Titan plus if I recall...

Crazyeddiethefirst said:

I second that- when there have been questions about if a light is as waterproof as advertised, I have multiple times frozen them like bykfixer' s examples. Last time was the Surefire Titan plus if I recall...

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In my previous post:
The top photo was one I left outside over night knowing a blizzard was coming. Next morning I un-buried it, turned it on and let mother nature recover it.

The bottom two were done by PK himself who used the heat of the light(s) to complete the melting process.


Here was a promo pic


Aftermath of the snow storm.
The car is lit by the light that had been left out the previous night

Ok then so it looks like LED's can definitely take a freezing.
Next question, does Anyone know of a highly light reflective, paintable substance that won't damage silicone and can take a good bit of heat? I was thinking of using spray on bumper chrome but not to sure how well it would cope.

Thom2022 said:

Ok then so it looks like LED's can definitely take a freezing.
Next question, does Anyone know of a highly light reflected be, paintable substance that won't damage silicone and can watch that and heat? I was thinking of using spray on bumper chrome but not to sure how well it would cope.

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Your freezer will not get remotely cold enough to cause any significant hardening of the silicone on an LED. Silicone is picked specifically for this reason to operate without thermal stress from below -40 to +125 (and up).