What is the goo? Adcom question.

[digital desire]

What is the goo that adcom used to secure the thermister to the driver transistor on 555's?
It comes apart easy, but the only heat sink compund I have seen is the typical white silicone type that does not have the viscosity that the grey stuff has.
Thanks!

 

[Minion]

The grey stuff could be a Silver or aluminum Paste...I use a Silver based heatsink compound on CPU Heatsinks and it is supposed to have the Best heat transfer of all Heatsink compounds....

The stuff I use is called "Arctic Silver" and it is a bit pricey but it does work very well.....


Cheers

 

[anatech]

Hi digital desire,
It was a thermal paste that got sort of harder. Similar to thermal epoxy but not as permanent. Anything that will hold the thermistor down and not short will be okay. You really don't want it to melt or soften with heat either. You could also use Wakefield Deltabond 155 (epoxy). It's wonderful stuff, worth it's weight in gold in a pinch.

If you need Arctic silver or the like, it's time to rethink your thermal problems! 😉

-Chris

 

[EchoWars]

JB Weld works good too...even conducts heat nicely.

 

[anatech]

Hi Glenn,
Sounds interesting. Do you have a link for that stuff? I'm always looking for alternatives to things. One never knows. 😉

Thanks,
-Chris

 

[EchoWars]

http://jbweld.net/products/jbweld.php

Hardens as a very tough plastic, has high solids content, and conducts heat nicely. Think of as epoxy on steroids.

 

[anatech]

Hi Glenn,
That I'm going to try and find. Wakefield Deltabond 155 runs about $60 CDN, so if this works it may save me some money.

-Chris

 

[EchoWars]

Common item in the hardware stores in the States. Not sure for you third-world guys...😉

 

[anatech]

Hi Glenn,
It's no good up here. We need stuff that is useful in sub-zero conditions.

-Chris

 

[digital desire]

I conisdered JB weld, but worry that if I need to take it apart again I would not be able.
I suppose I could just tuck in tight, and use the regular white heat tranfer sauce, but I was looking for the paste stuff.

Thanks anyway, I have yet another 555 now to fix, suppose I am starting a collection!

 

[anatech]

Hi digital desire,
I just desolder both parts and remove them as an assembly. No biggie.

-Chris

 

[valveitude]

Plain 'ol clear RTV silicon glue works beauty for this sort of thing. Silicon conducts heat well (witness the silicon heatsink insulators), and is easy to remove later.

-Casey

 

[anatech]

Hi Casey,
I would tend to use some heatsink compound (not too much) and have the thermister lay there naturally. Then use the silicone to ensure it stays there, so applied over top only.

I've done it that way with good success.

-Chris

 

[valveitude]

Hi Chris,

Yep, that would work better..though I have to admit to gluing some TO-220 transistors directly to a heatsink in place of the grease/insulator with some RTV once in a power reg I built years ago . It lived, but I wouldn't suggest it is a regular practice.

-Casey