What about various doughs, like that doughy eraser material, or that stuff used to put up posters, or even play-do? There's this if you can find a vendor.
This might be an excuse for me to buy a thermometer w/thermocouples.
The three usual ways to transfer heat are conduction, convection and radiation.
Good heat conductive materials are mostly metals that might cause short circuits, but there are others commonly used to cool electronics.
Air transfers heat by convection in all but the smallest systems. But its density (and therefore heat capacity) and heat conductivity are low. Most other fluids transfer heat better, but they have other problems.
Hard anodized aluminum radiates infra-red radiation well, but that works best if the thing to be cooled is quite hot. (I am confident in this. My boss looked it up when I told him my intuition should not be trusted.)
AA is kinda expensive to be using as a potting compound, isn’t it? It’s like 8 bucks for 5 grams.
I dont think so. Arctic stuff is developed to stick "ok" and transfer heat well. JB weld is developed to stick like hell and the rest is just a side effect. Arctic Alumina might even be better, but Arctic Silver certainly is. Its just expensive as hell..
Also, I cant really follow your arguing about RAM. If heatspreaders made of aluminium increase the surface area by a factor of 3, the chips will run cooler.
What happens? :P
'Designed to' and 'does' are two different things. Primarily, it's designed to appeal to people with enough spare cash to spend $15 on a tiny little tube of fairy dust (er... fairy juice?). Anyway, the thermal compounds market is ripe for exploitation of magical thinking, much the same as the 'audiophile' community where people pay a thousand bucks for a generic power cord and swear it makes a dramatic improvement in the sound quality.
Now explain to me how a flat rectangle of aluminum has more surface area than a PCB with eight multi-legged chips and capacitors and resistors soldered to it.
Use a copper heatspreader linked to the pill with copper wire (s). Take advantage of that super high heat conductivity. That's my plan. Some potting will just be used to accommodate components of different height and to prevent shorts.
Well, Arctic Silver has about the same thermal conductivity as some silver based thermal greases and a lot of tests show it has a pretty good thermal conductivity.
JB weld is in the range of <1W/mK. Arctic Silver is about 8. I agree with your point about hifi voodoo, but unless someone measures the difference between JB weld and AS to be negligible, I still use AS to glue my stars down. Fujik is about 1W/mK too.
I'm not sure we are talking about the same with the RAM heatsinking. The chips are usually not glued to the board, the large aluminium bars are glued to the chips. I doubt that no heatsinking would be better than 2 aluminium bars.
What about some jbweld mixed with aluminium powder…?
What about these stuff for filling car dents?
The uhu 2k glue I always use for repairing and so on has a thermal conductivity of about 0.25W/mK
Thanks everyone. Some good ideas and thoughts to ponder.
I ordered some of the thermal pads linked to by RaceR86 because they look good to have on hand.
I really like Comfy's JB Weld idea and will try it when if will fit my app. My current app has too many obstacles for it.
I may try leftye's idea (Post 27) in my current app as I have a copper pill that can be soldered to, but I really like the idea of just injecting silicone or something into the pill once I feel the light if finalized. The above thermal pads are silicone and are white. That indicates they probably contain alumina. I will search to see if their are any non-corrosive silicone products out there like that. I wonder how much alumina power can be mixed in silicone before it begins to become electrically conductive?
Alumina powder shouldn’t become conductive as it’s ceramic based. Unless you meant to say aluminum powder. That would be entirely different.
Since ceramic is an insulator, it shouldn’t ever produce a short. Just like in the good ole days where home wiring was exposed, without insulation of any type, and run in parallel rows through white ceramic insulators to the rotary switch.
Any RTV marked as 'oxygen sensor safe' is what you're looking for. Go to the auto parts store, not Lowe's/HD.
Now we are getting somewhere. Combining alumina powder and RTV marked as 'oxygen sensor safe' sounds like the solution I'm looking for. Thank you DBCstm and Comfychair!
Comfy, in your experience, does that RTV stuff peel/crumble off driver type surfaces fairly easily? If its like other gasket maker stuff like I have used in cars and bikes, I imagine it does.
Permatex Ultra Grey. It still sticks like hell, but it's not gooey/slippery/slimy like clear RTV when you have to scrape it off. It's much stiffer when cured.
Having trouble finding alumina powder locally. Checked craft stores (I've heard it could be used for polishing), harware stores, walmart, and auto stores.
I see it online in several places. Any idea on a potential local source?
EDIT: I found this, but don't know if it's pure alumina (aluminum oxide):
http://www.walmart.com/ip/Badger-Aluminum-Oxide-Abrasive-5Lb-Net-Wt/20773891
Dude, that’s 5 lbs of alumina oxide! You got a LOT of potting to do?
Edit: I have saved a bunch of the copper filings, mostly very small granules from using the cut-off wheel in my dremel tool, and I wonder if this can be added to JB Weld to enhance it’s thermal properties? It’s highly unlikely that it would make it electrically conductive as it would take a small miracle to align all the pieces of copper to make contact, hence conductivity.
Thoughts?
Yeah, I know. Searching for something smaller. Do you think it is essentially alumina powder? Or do you think it has other stuff. Googling right now and it sounds like it is just pure aluminum oxide powder. I would like to try this stuff for stropping.
I save copper and aluminum shavings too. Seems like it would work if you do what Comfy says and use that wax to fill places you don't want the JB to get to.
Been reading a bit. Sounds like zinc oxide powder could be better than aluminum oxide powder.
Now that some time has passed, it silicon carbide still considered to be a good potting compound? Here is an older thread on it:
Because….
…
Fairy Dust!!!
Wait, which side was I on?
Anyway, excuse me while I go hook up my new 24K Gold, Quad Shielded, Oxygen Free, Silver-coated conductor, Nitrogen (N2) Gas-injected dielectric, HexMesh Jacketed Monster HDMI Cable so I can truly enjoy Tinker Bell: Secret of the Wings. 
Everyone knows how badly digital signals degrade without Oxygen Free Quad Shield 24K Gold! Almost got Triple shield by mistake! 
By the way, having a real hard time finding a similar optical audio cable. I’d be happy with just Oxygen Free at this point! Can anyone hook me up?
Yeah, gold contacts on optical cables or magnets on digital cables are nonsense. But so far none of you has sad anything intelligent about RAM heatsinking being useless, so.. whatever. ;)