As it’s already been said, you don’t need silver. You don’t really need copper either. Aluminum is fine, and brass is good enough most of the time.
If you’re really that concerned about thermal performance, reducing the number of layers in the thermal pathway and minimizing the gaps between each interface is far more important than using premium metals.
Dale, please post a thread of that build.
AGREED!
Pics of hollow pill and the before/after please!
@Hank: Good to know. Noctigons are great. :)
I'm pretty sure aluminium Sinkpads are just regular PCBs with dielectric layer under the center pad. Its possible to solder to aluminium, but its not easy. Way easier to just use copper.
Copper/solder/whatever filling a pill doesnt improve heatsinking though. All it does is improve heat capacity.
It's not.
overexaturated of course…but you see how they provide the direct thermal connection
Home made sinkpad
You are right, they now offer aluminium PCBs with direct heat path. Last time I looked, they had copper and regular PCBs, but since its been about a year since I looked.. :D
Except for the fact that you cant connect the aluminium PCBs to the heatsink with solder, they should actually work better. But I wonder how they made the top surface solderable. Either pre-tinned or some special layer..
Probably pre-tinned
They do make low temp aluminum solder, it takes a few steps and special preparation to solder aluminum (namely cleaning with a STAINLESS STEEL brush to knock off the oxidation layer, but it is doable
I would think the easiest way would be to coat the aluminum board with copper, but I doubt that's the case. It's almost certainly pretinned, but that leaves a lot of questions too.
I need to get myself some of this copper solution stuff and try this out.
I guess in a factory you can easily solder aluminium. Something to keep the air from making contact with the aluminium and something to scratch away the oxidation layer and you are done. I tried that with an XRE aluminium board, solder, oil and a nail once. It worked but wasnt pretty at all.
I think I'll stick with copper boards. :P
THIS
Pennies are actually brass, 95% copper.
http://en.m.wikipedia.org/wiki/Penny\_(United_States_coin)
1962-81 and 44-46.
90% silver should beat that quite handily.
As far as cost, silver dimes maybe $3, sandpaper is $1.39 at the local hardware. So not bad. Plus the dimes are smaller in diameter. And I think silver is softer.
I might use other countries too.
I believe Wikipedia says Sterling, 92.5%, is 361, pure copper 400 or so, pure silver a bit higher.
85% Cu brass 151 on one site.
i have used AL. sinkpad2, it solders just like copper one, heatpad looks like it was plated or something, or pretinned, as mentioned before. but it is not AL on the surfice. the heatpad has continuity with back of the star
pennies? Have you tried that. pretty terrible compared to anything manufactured…
and a waste of time with 10, 16, 20 mm sinkpad and noctigon’s available.
thermal conductivity: 429 for pure silver vs 401 for pure copper
this is < 7% difference. Waste of time/money, and a coin that will increase in value.
I challenge you to measure the difference in a flashlight application.
I hate to sound offensive to another flashlight modding fan, but until you do I will consider this nonsense.
They're great for adding mass inside a pill.
I can agree with that, in fact, I have a big ziploc of pre 1982 pennies for adding mass…
but I’ve also found that if i can fit more than 2 or 3 thicknesses, I’d rather use a section of copper bar.
I bit the bullet and ordered 3 rods of different diameters a couple years ago. got a LOT of copper for < $40….
“work better” at transferring heat? nope.
A bar would be great. I may do that eventually. Unfortunately $40 doesn't buy much copper nowadays. At least I still have a copper lightning rod that I'll be pounding into filler when the pennies run out.
Dthrackt yes, pennies, as recommended here on blf. The manufactured xm-l on a hollow pill I got yesterday is inferior to pennies.
As you pointed out above, we’re dealing with alloys.
92.5% Sterling is over 100% better than 85% Cu.
If you didn’t want to sound offensive, might should’ve skipped that post
Maybe I should have written "could", but anyways, I think I read that copper has a higher conductivity rating but aluminium is faster at giving heat away (not emissivity). But since there is no real difference in performance between brass, copper and aluminium heatsinks, I dont think there will be much of a difference between aluminium and copper star..