Trying to replace LED chip on floodlight. What is the white stuff?

Old 10-02-15, 04:52 AM
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Trying to replace LED chip on floodlight. What is the white stuff?

Hi, first post

I opened up a 50W floodlight to replace the LED chip because it stopped working and there is this white stuff between the chip and the metal. The screws are also covered by this stuff.

What is it called?

I am thinking it is either a thermal insulator to separate the electrical components from the metal casing or it is a thermal heat-sink paste. If it is an insulator, then I will have to get some to put behind the new chip so that the casing doesn't conduct electricity.

It smells like paint/petroleum and somewhat sticky.

Here are pictures:

View image: IMG 0314

View image: IMG 0315
Old 10-02-15, 06:27 AM
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Looks like thermal paste. There may be an insulator as well, but it would be a thin sheet material, not just a paste. It's to help conduct heat away from the LED chip. zillions of sources online, and larger computer stores would also have it as it used between CPU chips and heatsink.
Old 10-02-15, 08:11 AM
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Yes...... it is thermal transfer grease. It's used to fill in the microscopic gaps between the LED engine and the heatsink.
Old 10-13-15, 04:28 PM
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It's heat sink compound. I have used quarts of it in my lifetime.

If insulation is also needed, a thin plastic or mica sheet is included.

Aren't you supposed to just replace the entire light?

And how do you know it is the LED chip that failed? In my experience, the power supply fails, not the LED.

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