"Pyrolytic Graphite"

It's good but expensive. Certainly better than using plastic in modern disposable engines. I've been reading lots of horror stories on new car engines.

It's diamagnetic and lightweight, so it can hover above permanent magnets.

Cheers

It's very anisotropic, with high thermal conductivity only in the plane of a sheet. That makes it useless for most electronic applications.

se

disposable engines. I've been reading lots of horror stories on new car e ngines.

It would be good for replacing the plastic valve cover of my Camry. Most d isposable engine like the Camry will be done when cooling is gone, mostly f rom the melted plastic cover. I am looking to replicate the cover in metal or PG. It might cost $1000 vs. $100 plastic cover, but cheaper than the $

On Tue, 18 Aug 2015 09:39:02 -0700 (PDT), snipped-for-privacy@gmail.com Gave us:

Carbon fiber.

All the car customizers and chopper builders have connections for metal plating, AL anodizing, carbon fiber stuff... all cheaper usually than you can go find it. Make friends with a biker that has a custom chopper *he* built.

But great for re entry nose cones and rocket nozzle liners.

Dan

I suspected that - they did illustrate it as a sort of flex-circuit heat pipe sort of thing.

Thermo conduction is more important than strength. Or perhaps carbon fiber on top of PG. It needs to last for several minutes, when the water pump g oes and before the engine explode. Modern disposable engines are built to last as long as the water pump, some are even made of plastic.

Possible. First is to replicate a mold that can withstand 2000C for PG, or perhaps just 1000C for aluminum. The cover needs to be an exact replicate of the plastic one.

It's diamagnetic enough that you can levitate it over a quadrupole made of permanent magnets. The more physics somebody knows, the bigger the double-take they do when you show them. ;)

Cheers

Phil Hobbs

I think I had calculated that it's 7 times worse in specific conductivity per price. So, if you *really* need that extra couple C/W shaved off your thermal spec (like, perhaps, some hapless engineer tasked with designing a Macbook in a titanium skin?...), and literally cannot spare another two thousandths of an inch clearance... maybe you'll spring for it.

For everything else, heck... a multilayer PCB outperforms any commercially available thickness of the stuff. So the list of situations where it's useful must be terribly small.

Through-plane conductivity doesn't matter much, since you'll mostly be sticking it to wide areas which will therefore have much higher cross section. (Same is true of PCBs, incidentally, which is why it's so beneficial to use thermal vias.)

I suppose it would tend to be somewhat EMI dissipative, so there's that, too. Speaking of, note it's conductive, so you can't just wrap your PCBs with it, anyway. An adhesive or film backed product is therefore even worse, thermally.

Tim

Well, yeah. It's the tooling material of choice for electrical discharge machining (of the 'sinker' type, not wire-cutting). It also makes a good susceptor for induction heating. You can put graphite around a crucible, and get molten metal from your kitchen microwave oven. Once, for sure.

Absolutely. Can also be used as a part of (DC) magnetic levitation due to its high diamagnetic properties. However, it is a tad expensive..

• Don't you have_any_ imagination? Use that property to carry heat AWAY from a pesky source..(not too hard to solve thermal coupling on both ends).

...and THAT is soooo cool!

Being conductive, wouldn't it frap the microwave?

Not enough to do dumb things.

Check out the pricing for small, thin pieces of the stuff:

That would be insane as a heat spreader. Aluminum or copper make way more sense.

well, yeah, but so does charcoal, and cheaper

The oven box is conductive the air is an insulator.

So long as there is _a_ resistor with sufficient radio cross section in the microwave you are fine, dunno what the cross section of half a glass of water is, pretty small I expect.

You can buy it with a thin film of insulator and adhesive on one side. It's excellent for cooling SMDs when there's no easy way to surround it with lots of unetched copper. Press it over the top of the SMD or under the board. A small strip from an SMD to a nearby case can move a few watts. It's amazing stuff.

I used it a lot in very small hobby projects where copper foil is too bulky. I've seen it in an Apple Macbook Pro wall wart. Most cell phones use it for distributing heat from the main board.

Actually, the 90x60 is reasonably priced at $3.29. The 230x130 (10x area) is expensive at $91 (30x price). So, my 1000x300 valve cover liner (100x area) should cost between $500 to $1500, if we can make it that big.

I just need a big enough vacuum CVD chamber at 2000C.