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What kind of material to use? Answered

Okay I've procrastinated long enough to do something with my ibook's heatsink. As some may or may not know, ibooks come with thermal pads, which I unwittedly removed the old one off mine, thinking it could be replaced with good old generic thermal paste..which technically would be better for it.

Unfortunatly folks the heatsink wasn't designed to clamp down onto the cpu like a normal heatsink should do, as it has to cover several different gpu/memory chips of different sizes, making a small gap between the heatsink and cpu.

I've heard of people using a square or even round piece of steel or copper or something to wedge in with some thermal paste. Well, all I can think of off hand to use that might work is some sheet metal that has some white paint or something coated on one side, and a round steel (?) rod out of an old printer that's been sitting around. I presume the latter would probably be better.

Can someone suggest what would be best? Should I try cutting it with a hack saw or try getting someone's bandsaw so I can get a better cut? Right now my ibook is reporting a cpu temp of 53 of Celcious, which really, compared to when it's turned on from a cold start, is really F***** slow and very laggy, it often hangs for minutes at a time. It's horrible to use sometimes, but at the same time it owes me absolutely nothing so I won't cry if it burns out.


. Using that chart, I'd go with Cu because of the lower expansion coefficient. In the Real World, it probably won't make much difference - go with whichever you can find in the proper thickness.

Orrrr, if I were to have the time/resources, a really thin wafer of aluminum and copper would probably top it, this ain't the case however. So basically I can grind the edge off a penny and use that?

youd not only need to sand the penny, youd need to lap it. go to metku.net under modding for a guide on lapping.

Lapping is basically just sanding/smoothing the surface out to a shiny goodness right? I have a large dremel tool collection, I'm sure theres something in there I can use?

shiney/mirror surface yes. but no, there is nothing in your dremel collection for this. plus, you need to wet sand.

There's a set of these blue dremel grinding bits that are almost soft to the touch, perhaps these may be wet sand grinding stones?

stop being lazy, and get some real sandpaper to do a good job.

. . I don't think you'll be able to get a perfectly flat surface, as required, using a Dremel. Lay a piece of sandpaper (the finer, the better; at least 600 grit) on a hard, flat surface. Wrap some tape on your finger(s), sticky side out. Use your taped finger(s) to rub the metal against the sandpaper in a circular motion. Use plenty of water (and sandpaper made for wet sanding). Try to keep the faces as parallel as possible. For final polishing, I'd use a black whetstone and some light oil.

AH ha, I got some whetstones, what are the smaller white ones for?

. With the natural ones that I get in Hot Springs, AR, US, the rule-of-thumb is; the lighter the color the coarser the stone - black ones are the finest. For synthetic 'stones, I dunno.

the white ones i have are fairly coarse. the brow ones are uber soft. so nacho is right.

. Quite possibly, but maybe not. Rub your fingers on it and see. If it feel grainy, it's coarse; if it feels slick, it's fine. Very fine whetstones will have an almost glossy finish.

perhaps you did not understand me.

your dremel is the wrong tool

you will have to use sandpaper and your hands. plus, you cannot wet sand with a dremel.

Hmm, I am not sure about the coefficiency of Zinc....

Pennies are no longer made of a high percentage of copper, remember ?

I'd recommend copper. If you do use the sheet metal sand the paint off, and then clean it.