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Thermal paste or silicone tape ?

Gervais Cote

Predator
Hi gents,

I'm just wandering if these two methods to allow heat transfer from output transistors to heat sink are both as good as each other.

I am more familiar with the thermal paste and when rather new and applied properly it transfers the heat very well but I'm a bit skeptical about the efficiency of the silicone tape.........

Worst case, is it a good idea to use both the silicone tape AND thermal paste or I should stick to the existing heat transfer method only ?

For those not familiar with the silicone tape, here is an example :



Thanks in advance.
 
Mica and silicone grease is better, but that tape you show looks like keratherm, and it's pretty good too, for a hell of a lot less mess. If you are not running the transistors on their bleeding edge thermally, kerathetm should be fine.
 
Getting good quality mica is not easy these days.
If you are not sure what you are doing, leave power transistors alone.
It is very easy to get a burr or swarf from the screw hole puncture the insulator.
 
I use ceramic and silicon grease.

Insulators Part Number - 4180G Aluminum Oxide Ceramic Aluminum oxide insulating washers have a dielectric strength of approximately 21.7 x 103 volts/mm for .76mm material (550 volts/mil for 0.030 inch materail) and 16.9 x 103 volts/mm for 1.57mm material (430 volts/mil for 0.062 inch materail). The thermal conductivity of aluminum oxide is 15.06 W/mK at 75° (167° F) [8.71 BTU/hr-ft° F]. Aluminum oxide has unique thermal conductivity qualities and features low loss factors at high frequencies. It has high compressive strengths, high volume resistivity, low thermal expansion and it resists radiation. Note: Hole diameters are +/- .13mm (.500"), angularity is +/- 1° and flatness is .05mm (.002") TIR unless otherwise specified.
 
Hi gents,

I'm just wandering if these two methods to allow heat transfer from output transistors to heat sink are both as good as each other.

I am more familiar with the thermal paste and when rather new and applied properly it transfers the heat very well but I'm a bit skeptical about the efficiency of the silicone tape.........

Worst case, is it a good idea to use both the silicone tape AND thermal paste or I should stick to the existing heat transfer method only ?

For those not familiar with the silicone tape, here is an example :



Thanks in advance.


Is that an MF P170?, to your question silicone pads are the easiest to use, as has been pointed out make sure the surfaces are smooth, I use emery paper, wash the surfaces and visual inspection and never lost a transistor in forty odd years of DIY and I hate anything mechanical.
 
Is that an MF P170?, to your question silicone pads are the easiest to use, as has been pointed out make sure the surfaces are smooth, I use emery paper, wash the surfaces and visual inspection and never lost a transistor in forty odd years of DIY and I hate anything mechanical.
Yes it’s a P170 in rather great condition but in need for a recap and a few new resistors that got some heat. Trafos are from 1987 but final assembly was done in 1988. Can’t wait to hear it !
 
If it matters, its all about W/mK.. Watts per meter-Kelvin.
Higher is better, lower is worse.

I tend to use Thermalright Thermal Pads which are 12.8 W/mK for anything thermally critical, thermal paste is generally better, and the cheap blue thermal pads are generally (a lot) worse.

https://www.amazon.co.uk/dp/B08CGL7MLN/?tag=pinkfishmedia-21
 
This site contains affiliate links for which pink fish media may be compensated.
Hi gents,

I'm just wandering if these two methods to allow heat transfer from output transistors to heat sink are both as good as each other.

I am more familiar with the thermal paste and when rather new and applied properly it transfers the heat very well but I'm a bit skeptical about the efficiency of the silicone tape.........

Worst case, is it a good idea to use both the silicone tape AND thermal paste or I should stick to the existing heat transfer method only ?

For those not familiar with the silicone tape, here is an example :



Thanks in advance.

I would use what I am more used to working with. If you are used to thermal paste, use it.
 


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