Has anyone dissected an aluminum Sinkpad? Is there a copper trace just without the dielectric?
SinkPAD's site (http://www.sinkpad.com/what-is-sinkpad.php) says the average star is 1-4 W/m.K, and the aluminum SinkPAD is 135 W/m.K, then copper SinkPAD is 385 W/m.K, so the major improvement is removal of the dielectric layer.
In their presentation (http://www.sinkpad.com/sinkpad-presentation.php) interesting in that they identify a "thermally conductive" dielectric. They call it MCPCB Type 2. So it appears there is difference in the stock aluminum stars out there, and even if they have a dielectric layer, it could be a "good" one or "bad" one.
Everything I see on their site is saying the aluminum SinkPAD is the same exact design as the copper one, just different base metal used.
Since comfy frequently brings up how copper pills don't work any better than aluminum pills, I wonder if the same would be true with direct bonded mcpcb's. I'm betting testing would come up with the same results for both aluminum and copper direct bonded mcpcb's, but I'm rooting for copper.
The aluminum MTG2 stars from Cutter have a layer of pure evil where the dielectric would usually be. It eats drill bits like you wouldn't believe.
Using copper on a PCB definitely shows output improvement, mostly because the heat density is much higher compared to a pill.
Match’s tests:
But is that improvement from the copper or from the elimination of the dielectric layer... that the improvement exists isn't the question.
Whoops, that’s true, sorry about that.
I vaguely remember a discussion that concluded that copper PCB’s with a dielectric layer was similar to an aluminium PCB rather than a SinkPad/Noctigon.
Ok where is the lumen graph for copper sinkpad and alum sinkpad ?
No one has done that, aluminium Sinkpads are not widely spread so there is no output graph of it
I have 10 sinkpads that I got as free samples, some aluminum and some copper. Does anyone want a copper XM-L and an aluminum XM-L bare sinkpad for some testing? Shoot me a PM, and I’ll try and hook you up.
A machinist told me that the alum might be better . We need to find out.
I see a little project coming up: a kind BLF-er (Slim Pickens) has just this week offered me some aluminium Sinkpads for the Luxeon TX (that I do not posess as yet, by the way). and I would not mind finding out what the aluminium ones do compared to copper, so yes, I would like them, but I do have a spare 20mm copper Sinkpad, so unless it is not going to be used anyway (I will never say no to an extra Sinkpad :-) ) I am already happy with just the aluminium one. PM sent.
It seems you are right Old-Lumens. I removed the sst-90, hit the board with a dremel and tested it with the DMM. All results point to direct copper.
Test the board as is, the way the emitter will see it. If you have continuity then you should also have a direct thermal path. And that board is not the one they showed in the link.
Because I’m stupid and I like to do things the hard way :Sp I can find another way to mount the led, it doesn’t really bother me.
I hadn’t picked up on the board being a different colour. The specs are the same in every other way though.
It appears the white boards are sold out.
Actually, it would. Diamond, except for blue and doped synthetic, is a non-conductor and would constitute it's own dielectric layer.
i think what he is saying is that when you hit the board with a dremel , you are grinding down to the copper, and now you have no idea if it was direct to copper before you dremeled it.
If there is a separate dielectric layer, it is the dielectric that determines the thermal properties, not what it is on top of. A diamond board with no dielectric layer would not have a separate dielectric layer, just like a direct copper board has no dielectric layer... hence why on purpose I included the words 'and a dielectric layer' in there.
Honestly I was just to lazy to scratch it by hand and my train of thought was a dielectric layer would be easy to see anyway. I did a dremel scratch on the original sst-50 board to double check myself.
Sorry, my photography skills suck.
I could be wrong about this, so I am asking, should you have scratched it at all. ? If you test to see if the led goes thermally direct to copper, don’t you test from where the led would be, instead of scratching down to the copper ?