# ways to waterproof a LED



## mds82 (Aug 12, 2011)

Hi All.
I'm working on building a light bar to go inside the bed of my friends truck bed and need to find a way to make the LED's waterproof, or at least water resistant. I know the LEDSupply sells LED Seal, but i'm not 100% sold on it.

Basically i am going to be using a 5 ft aluminum, 3 XP-g's on stars, and the LEDSupply 1400mA BuckBlock ( which is waterproof). I'll be building 1 bar for each side of the truck so it will be plenty bright!

For waterproofing, i was thinking of just putting a coating of clear RTV Silicone on top of the LED's, but not sure if they can take the direct heat of the LED. I know the silicone would disperse the light but that would actually be better anyways.

Any other ideas on how to make the LED's water resistant or waterproof?


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## blasterman (Aug 12, 2011)

Use C-channel / U-channel aluminum and epoxy some plexi or diffuser over the top.


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## Steve K (Aug 12, 2011)

Putting RTV over the LED itself seems like poor option. Better to find some clear plastic dome/cover and use RTV to attach & seal it. 

I did this with a bike light, although I did make the cover from clear plexiglass sheet. A clear plastic tube, sawn in half, might be a good option. A bit of flat plexiglass at the ends to seal things up.

...or mount the LEDs within the aluminum channel, and throw flat plexiglass over the top and sides. I did this in a bike taillight. ... pretty much what Blasterman suggested....

regards,
Steve K.


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## DIWdiver (Aug 13, 2011)

Call your local Dow Corning rep and ask him about conformal coating materials. I have little doubt s/he could recommend something appropriate.


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## Gene43 (Aug 14, 2011)

I have generally had bad results encapsulating LED's without some sort of cover protecting the LED's from the encapsulant. Either high lumen loss or LED's just stop working after a period of time.


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## Foxx510 (Aug 16, 2011)

The leds will need some physical protection also, unless I've missed something. Maybe that can be waterproof too. As suggested, some clear plastic tube perhaps? I'd look at some wide angle optics personally, neatly inserted into some al channel or tube.


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## Mark620 (Aug 16, 2011)

One thing not to use is silicone - bad for electronics


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## CKOD (Aug 17, 2011)

Mark620 said:


> One thing not to use is silicone - bad for electronics


 
generalizations are always wrong 

But for benefit of the doubt, I'll assume youre talking about acid cure RTV silicones which have an acetic acid vapor which will corrode copper and cause other problems as it cures. If youre using RTV silicone you need to use "sensor safe" if youre using automotive stuff, or neutral cure or alkoxy cure which emits methyl and ethyl alcohol vapors as they cure. 

2 part tin cure and platnum cure silicones are both typically fine.


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## Ken_McE (Aug 17, 2011)

mds82 said:


> i was thinking of just putting a coating of clear RTV Silicone on top of the LED's



After enough time going down the road, I expect that the silicone will turn greyish and collect surface dirt that is impossible to remove.


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## Chicago X (Aug 17, 2011)

You nailed it in your first post - LED Seal !

This is a silicone-based spray made to go directly onto the phosphor layer to prevent damage and oxidation. It is optically clear and made for the exact purpose you describe in the thread. 

As others have mentioned, some type of impact resistant material should be utilized in addition to the LED seal.


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## saabluster (Aug 17, 2011)

For all intents and purposes XP-Gs *are* waterproof. They use a newer type of silicone that water does not impregnate as easily. I wouldn't submerge these for extended periods of time but they won't get hurt from a little water. I would be more concerned that they are protected from physical damage. Blasterman's suggestion in that regard seems good. If you do want a silicone you can use to pot it with let me know.


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## mds82 (Aug 18, 2011)

Thansk everyone for the great comments. I'm not so much worried about physical damage and i think i'm going to stick with the LED Seal. These arent going to be going underwater just exposed to a bit of moisture from time to time. I'll post pictures of everythign when i'm done.


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## Mark620 (Aug 18, 2011)

CKOD said:


> generalizations are always wrong But for benefit of the doubt, I'll assume youre talking about acid cure RTV silicones which have an acetic acid vapor which will corrode copper and cause other problems as it cures.


 Yes, RTV silicones...


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