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LED/PCB mods. I adapt cheap led lights. Will gooping the pcb to weatherproof it shorten life? Answered

I'm an old electrician obsessed with LEDs and selling them to my old customers. I build custom landscape fixtures and have been purchasing cheap led lights and bastardizing them for parts. I've had several that moisture got to the pcb and it died of various causes. I've been gooping the supply wire solder points among other things to increase durability. If I goop the entire back of the board the smd is on, will it cook itself?  Any other ideas to increase durability without shortening life expectancy drastically will be greatly appreciated.



What are you using as "goop" ?

There are a couple of ways, one is to use a heavy duty "tropicalising" varnish, designed to coat circuit being used in high humidity environments, and another has been to "pot" (cast ) them into a block, either with a transparent resin or with ordinary paraffin wax. Polyester resins work, if they are applied in thinish sections - too thick, and the cure heat cooks your circuits. Epoxy is "the best"

Casting DOES affect heat dissipation, so you have to be careful with parts that dissipate heat by convection, or else, again, something will DIE,


For sure you SHOULD NOT attempt to weather proof anything with exposed metal circuity (circuit board traces, switches, etc.) with silicone sealer (caulking compound)
That material contains an acid (such as the kind used in photography ascetic acid)
You can purchase silicone sealer that's safe to use with electrical and electronic project but it's more costly. probably X4 $ or more.


8 years ago

Chances are, you'll be fine.  But here's an experiment:  Let an LED light run for, say, two hours and see if any parts get hot.  By hot, I mean too hot to touch.  If not, then go ahead and coat it with whatever silicone or epoxy or resin you like.  If it does get too hot to touch, then you can still coat the PCB, just make sure it's a nice thin layer where the hot part is.

Cheese-wax? Low-melting, recycled, waterproof, sticky. I've got at least a pound in a big ball, but not used it for anything, yet.


It might, but if so it's going to melt off the plastic-component-cases and stay on the metal pins I'd think.