Thermal Epoxy

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Does anyone know where I can purchase thermal epoxy? I have some small
copper heatsinks that I want to attach to some transistors. Jaycar and
DSE don't appear to have it, and a search for thermal epoxy on
farnell.com also produced nothing. I could, of course, be searching for
the wrong thing....

Many thanks

Re: Thermal Epoxy


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I get great results from close fitting heatsink / transistor surfaces
and superglue. It's possible to speed up drying by putting a few drops
of water over the glued items to keep air away from the glue which then
sets.

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I assume superglue is a good thermal conductor???

3m is probably the best bet. Although the OP gives no idea on
quantity, 3m reps are usually very helpful. I have used a thermal
epoxy from 3m for temperature compensation in conductivity sensors
with very good results. Highly recommended.

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I'm inclined to think it's not, but then even thermal grease is not
a good conductor of heat compared to metals such as aluminium or
copper and silver, the secret to using thermal grease is to use as
little as possible to ensure the two have air free contact. When
I use the superglue the heatsink gets fairly hot so I'm assuming
there's a transfer of heat. Most conventional epoxy's go jelly soft
with heating.

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I am not sure what they use in thermal epoxy, but it looks like it has
aluminium in it and it stays rock solid at any temperature that a
semiconductor will ever get to without catching on fire.

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Thanks to everyone who replied. I have stumbled across a product called
Arctic Silver Thermal Epoxy, which looks like it will do what I want.
Bunnings didn't appear to have anything that was mentioned here, and RS
want a hundred bucks for the loctite product, which is more than I spent
on the circuitry. Normally I use screws and thermal grease to attach
heatsinks, but in this case I packed everything too close together to
make that possible.

Thanks again

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It's actually moisture that causes superglue to set, and yeah, water works
great.


--

Bye.
   Jasen

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Ahh so that's how it works!.

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Bicarb of soda will also accelerate superglue setting,.




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As it supplies the OH- hydroxyl ions that water can supply, but
more of it....thanks!.

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The transistors don't have a bolt hole for mounting on a heatsink ?





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@fe03.news.easynews.com:

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As far as I know, most epoxies are thermoplastic, which means they will
soften with temperature. There are cyclo-allophatic thermosetting ones but
probably harder to get. You can use a thermal acrylic designed for the job
such as Loctite "Output". This works well for heatsinks. I think it is
avaliable from RS and I seem to remember seeing it at Bunnings once.

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most hardware stores carry epoxy putty , its used as a filler and in air
conditioning .

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As long as you dont want high mechanical strength, silicone RTV works
better than epoxy.  Conductivity is higher, and strength doesnt degrade
with temperature.  Make sure you use the neutral cure type, so you dont
get corrosion from the acetic acid released from some other types of
silicone.

--
Regards,

Adrian Jansen           adrianjansen at internode dot on dot net
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Also some of the common RTV's like Loctite blue are good in high vacuum
environments, but not super high vacuums as they don't outgas too much.

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yes wes components
www.wescomponents.com
phone 02-97979866

heatsink glue drys like hard rubber
code number TSE3843W  cost $38.50

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