Thermal glue & power resistors?

I recently received some parts for deal extreme that will be used for reprap related projects.

Parts from DX

From left to right:

I plan to use the scale to conduct peel tests of different print bed materials once I get a Mendel built. It could also be used for a range of tensile tests to determine if a plastic has undergone any changes to its flow stress after extrusion.

The 45kg digital scale.

As an added bonus this scale also has an inbuilt digital thermometer for ambient air temperature readings.

The solder paste and flux will both be used for re-flow soldering components onto PCB’s for the Mendels electronics.

The heat sink glue compound I have used a lot in the past for attaching power LED’s to heat sinks. It seems to hold its strength even at high temperature. The aim is to be able to use this thermal adhesive to attach power resistors to a heated print bed so that they don’t need to be fixed with screws, which can be a problem for thin metal sheets.

With this in mind I used the thermal adhesive compound to attach a power resistor to a heat sink and let it cure for a few hours.

The single 15W power resistor warming up while attached to a cut heat sink.

I then brought it up to temperature, measured with a thermistor, and tried to remove it from the heat sink. At around a 120ºC it remain attached. I was unable to get a good reading of the temperature above 120ºC as it falls out of the range of this thermistor.

I suspect this thermoset heat sinking compound could handle a lot higher temperatures, all be it with a reduced bond strength. Slightly roughening the surface before joining and leaving it to cure for longer could will also help.

So all in all, lots of useful things all for just over $20USD.

About Richard

I am a Materials Engineering working in the field of Magnetic Materials in Melbourne, Australia. This blog covers my personal interest in all things CNC.
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2 Responses to Thermal glue & power resistors?

    • Richard says:

      I just did a quick test with a soldering iron set to 450 degrees C and there seems to be no burn through, even after holding for 30 seconds. However at that high temperature it did smoke a little. Set to 250 degrees C, which is just below its rating, there was no smoke or marks left on the tape. This is impressive considering the price.

      So yes, thankfully it seems to be safe to use on a extruder.

      There seems to be a few different listings of the “Polyimide Heat Resistant” tape on DX, maybe you got a different one? Or perhaps the supplier got caught out passing on fake tape and has since been replaced with the real thing.

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