Misc. questions on applying heatsinks & mixing adhesive...

Xylo

Limp Gawd
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Jul 5, 2005
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I want to apply a few heatsinks to some of the RAM chips on my graphics card when I water cool it, and also to a couple spots on my motherboard...a couple quick questions...

1) I know if you "mix" AS epoxy w/ the regular AS 5, you can (hopefully) later remove the heat sinks if you ever need to RMA the product. Can someone give me some more specific information on doing this? Do you just mix 1/4 epoxy part A, 1/4 epoxy part B, and 1/2 AS5?...or do you mix the epoxy alone, then add the AS5?...or?...

2) After doing the above, just how feasible is it later that you will be able to remove the heatsinks later on? Or, on the other hand, will you have any problems with the heatsinks not being affixed firmly enough? (It all comes down the mixture?)

3) a) Is there any reason why applying a heatsink to a chip that is slightly bigger than the chip would be bad?...I can't think of any at all (and have even seen such stock solutions). 3) b) But more importantly, what about one large heat sink bridging 2 small chips (on the motherboard in this case)? Any real problems with that? (I guess you run the risk of heating up one chip unnecessarily if the other is substantially hotter, but is that a real issue?)

4) a) Since the AS is non conductive, but can cause some capacitance, the AS website says to line the chip leads with a "non-corrosive silicone". Can anyone recommend something in particular? I live right around the corner from an auto-parts shop...there's also a small mom&pop hardware store near by too...

4) b) Also, will applying such silicone invalidate my warranty, I assume?...I wouldn't imagine, also, that there is any way to really get it off later...?


Thanks!
Xylo
 
Uhm, I use the artic ceramic alumina crap when its time to glue something on.

I see no reason to mix it. I mean its not just epoxy AFAIK........


And dont put it on ANYTHING you plan on sending back. If its that important, use some thermal tape.......



imo, you are trying to overdo things a bit. I know you arent asking for opinions here, but if it was me, i'd try a fan pointed at whatever random thing you are trying to cool and measure its effectiveness before you start attaching heatsinks to things that generally dont have them. (and i've done plenty of that)


3) a) Is there any reason why applying a heatsink to a chip that is slightly bigger than the chip would be bad?...I can't think of any at all (and have even seen such stock solutions).

Done this many times, no real problems as long as you realize that the much larger heatsink, glued to a chip, has a lot more leverage if you happen to move the case around or hit it with you hand or something. Just be careful.


If you do try and remove an epoxied heatsink....try tossing it in the freezer for a while first.

And have fun trying to get the small bits of epoxy that stick to the chip off....
 
arctic_adhesive.jpg

That's about the ratio I've used in the past and I've never had a problem removing the heatsinks. That was back in the day of old geforce2 style mem chips. BBA chips on modern cards come off ALOT more easily. I personally wouldn't recommend using adhesive on BBA chips at all frankly.

My personal solution right now for my card is to use some quality thin thermal tape to attach the heatsink to each chip. Push it on real hard, and then glue around it with a glue gun. The glue from glue guns comes off quite easily if you want it to. This way there is no risk of ripping a chip off.
 
Aaron_ATX said:
Uhm, I use the artic ceramic alumina crap when its time to glue something on.

I see no reason to mix it. I mean its not just epoxy AFAIK........

I realize that. The reason is to make it less "permanent"...

Aaron_ATX said:
imo, you are trying to overdo things a bit. I know you arent asking for opinions here, but if it was me, i'd try a fan pointed at whatever random thing you are trying to cool and measure its effectiveness before you start attaching heatsinks to things that generally dont have them. (and i've done plenty of that)

Well, fans are loud, and since the system is going to be water cooled, I'm trying to keep the noise and # of fans low. :)
 
Gotcha. Personally i'd be more worried about the effect that mixing the epoxy and the thermal compound would have on its heat transfer properties. Cause if it has a negative effect it seems like its a bit counter productive. But I really dont know.


Ok, i'll shutup now since im not being much help :)
 
Mixing AS5 and ASA increases the thermal conductivity of the ASA and makes it easier to remove the heatsinks.

I use a 50/50 mix of ASA and AS5 as is recomended on the AS site.

To avoid getting the mixture on the pins and legs of chips stick a large piece of insulation tap over the legs.
Use your fingernail or something to get it stuck to the legs right up against the plastic.
Just pull it out afterwards.

You will also find that many, to all, chips are slightly concave.
Sanding them flat helps a lot.
I've ground a stuffed Southbridge and some RAM chips in half to see how deep the silicon is below the plastic.
All of them have at least 0.8mm of plastic above the silicon.
So dont be afraid of going too far.
Be carefull of surrounding components though.
:)
 
Dunno said:
Let us know how it goes.
:)
But don't test ripping off the heatsinks! Save that pain for a rainy day next year when you're ready to sell your card or whatever...:cool:
 
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