Did you just sand it, or actually lap it (as in, used a piece of float glass, or a definitively flat surface like a specifically machined block of metal)?
Simply sanding it will result in a shiny copper top, but may leave it an uneven surface. Lapping gives it a proper flat surface, which is much more important.
You may wish to lap (properly lap) your H100i block too. They're shiny, but not always flat.
That looks pretty uneven, and judging from the marks not done on a mirror or flat surface (like FlawlessSoul said), or finished with 2500grit.
Here is what it looks like when you use a mirror: http://i.imgur.com/O2kJvCj.jpg I also made "8's" to evenly sand it. No striping/circular motions.
You made striping motions, which created an unflat surface. You can tell from the edges, they're more rounded off than the rest of the surface. Get a lapkit, a mirror, and redo the lap. Curing is a myth, most TIM's have no curing time anymore.
Admitted, it's going to be really hard getting it flat again with no possibility of creating a level refference.
Here's a nice example of how poorly made the IHS to begin with:
http://i.imgur.com/XqPT1Ho.jpg
well it looked like your bad example at first with the shades of grey still being there. (those were all gone when i was done with grid 600)
method i used was a glass table in the living room with the sanding paper taped to it and sliding the IHS over it back and forth. (didn't make 8's though)
perhaps i just need to invest some more time in it. (or find a way to acquire a seperate IHS )
Do you guys even realize that blocks/contactbases aren't designed for flat HSP's? The few degrees you gain from lapping isn't worth it, just improve your cooling.. Especially with a delidded IB, you need to put more pressure and you get a chance cracking the die.
That's why i also lapped the heatsink base.
http://i.imgur.com/atNnArh.jpg
General form?
Why would anyone need to RMA a heatsink while a H100 can easily die within 2 weeks? Happened to me quite a lot. Because you don't care about warranty doesn't mean you care wasting 120$ for nothing. Lapping IHS is kinda useless if you don't lap your cooler..
I've posted in this thread, but that was a couple of years ago and my setup has drastically changed since then. So I figured I'd give it an update.
Computer
CPU: AMD FX-8350 @ 4.00ghz
CPU Cooler: Antec Kuhler H20 620 Liquid Cooling Loop
GPU: XFX Radeon HD 7970 GHz Edition
RAM: Corsair Vengeance 16gbs @ 1866mhz
Mainboard: Gigabyte GA-990FXA-UD3
HDD1: Seagate Barracuda 1TB 7200rpm
HDD2: Western Digital Velociraptor 150gb 10000rpm
SSD: OCZ Vertex 3 120gb
ODD: Asus BD-ROM Drive
PSU: Corsair TX650M Semi-Modular
Case: Corsair White Graphite 600T
Peripherals
Keyboard: Corsair K90
Mouse: Razer Naga Molten Edition
Headset: Razer Chimaera
Monitors: LG 23EA63 IPS Panel x3
WoW Character: Wintel - Frostmourne (OCE)
Gaming rig: i7 7700K, GTX 1080 Ti, 16GB DDR4, BenQ 144hz 1440p
Signature art courtesy of Blitzkatze