[Katherine Swift]

This question comes from Randal:

I am trying to replicate something similar to what is referred to as “string” or “fairy” LEDs. Basically it is some electrical wires that have soldered LED chips directly on them and they appear to be encased in resin or something very similar. I know it’s not hot glue.

My guess, is that they are using a doming resin to encapsulate the LED and wires to seal them?
Not sure how they would be able to do it in mass.

I am making something similar with an RGB LED on a small circuit board that will have electrical wires attached and need to encapsulate them in resin to secure the wires and protect the LED circuits from moisture. Basically for use in Christmas tree lights or other decoration.

Does it look like a doming resin in the example pictures?

 

 

 

 

[Katherine Swift]

Hi Randal,

In order for this to be a doming resin, it would have to cure quite quickly to keep the dome. Otherwise, I would expect it to be much flatter than the pictures show. My bet is that the domes were applied with a glue gun.

If you wanted to try with resin, use a five minute epoxy. (The two part stuff you find in a plunger at the hardware store.) That’s the best way I would expect for you to get a dome using resin.

If you try this, would you mind letting me know how it goes?

[Randal]

I did testing a heat gun at about 300c and it did not melt. It doesn’t seem to be hot glue.

I’ll look into some two part epoxy to try out.

Thank You.

[Katherine Swift]

Good to know. Let me know if the other resin works.

[Sean M.]

@Randal: Did you ever find an answer about what they’re encased in? My guess is it’s UV-cured, but I’m not certain.

[Author]

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