R9 290x (Crap) Stock Heatsink... How To Lap?

[Sasqui]

Thanks to Solaris17 in this thread: http://www.techpowerup.com/forums/threads/my-xfx-290x-teardown-56k.196249/ for help in doing this...

My temps have been really high on a Sapphire BF4 R9 290x, so I tore the stock HS off to replace the TIM as Solaris17's teardown, he did a great job with it.

Everything went smoothly, thermal pads are intact. As in the Solaris17's teardown, the TIM looked just like bubblegum with several areas on the die that appeared not to have any contact at all:

And here's what blows my mind! The circled areas (in red) are divots in the copper HS surface! Straight from the factory...

Any suggestions on how to lap this? The heatsink doesn't appear to be removable from the plate.

 

[SKBARON]

I do not think lapping would be a good choice since you would increase the gap between the heatsink and the gpu, that is if the heatsink can't be brought closer to the gpu with a little bit more torque on the screws. I'd try and either rma the card or buy some aftermarket cooler for it. Maybe more experienced members have better suggestions.

 

[d1nky]

Piece of glass or something extremely flat that will fit in that gap.

Wet n dry, Tape the paper to the glass so it's tight.

Wet and dry from low grit to high grit, alcohol or something for the rubbing agent.

Last lap performed dry with 1200 grit. Lap in the same direction and not circular, you'll see why!


Edit: lapping wouldn't take that much of metal off from the sink, maybe a fraction of a mill if gently done. Or enough to make smooth. Also there is probably enough play on the parts!

 

[Shambles1980]

i dont think lapping would help with that, the dents seem a bit to deep. but it could be the picture...
Personally.. id get a new heat sink.
it just seems like a bit of a waste of effort. and the area is a nightmare to try and finish properly unless you can tear it down more.

 

[Vario]

you could try reassembling it as close to factory as possible (shin etsu paste glob) and see if you can RMA it for temps, if they disassemble it it will be obvious the heatsink is defective.

 

[Sasqui]

Piece of glass or something extremely flat that will fit in that gap.

I called the hardware store before even seeing your post and they thought they could make me a small piece of glass, but they were closing!

So,I'm using a few pieces of maple, each a little larger than a postage stamp, very flat going through 120-200-400 grit attached via contact cement. Pics will follow...

 

[erocker]

See if you can get a thin copper shim from the hardware store instead of glass. Glass isn't the best idea since it can shatter as well as not being a very good with heat.

 

[OneMoar]

if you have the know-how gets some pipe solder and a propane torch and fill the surface with solder let if fully cool then carefully sand and polish the extra off until its flat(be careful not to overheat the copper) this method will yield better results then a copper shim
iv done this with laptop coolers just make sure you use plenty of pipe flux and give it a though cleaning and good scuff with 1000 or 1200 git sand paper before hand if you can find it lead-based solder would be the best choice ELECTRONICS SOLDER WILL NOT WORK HERE IT WILL PEEL OFF AND CAUSE SHORTS!! MUST BE EITHER LEAD-tin mix OR PIPE SOLDER also flux core isn't isn't a good idea as it can lead to weak bonding
either that or open a RMA with sapphire and have them send you a new cooler generally they will send you a replacement cooler at no charge

 

[Shambles1980]

brazing or soldering with hot water copper pipe solder to fill the dents is probably the only way to actually be able to fix that properly.. But seriously, the amount of work that will need to go in to getting it done properly with the correct finish you would better spend on a good after market cooling system.
perhaps the 4-5 hours to do it well is worth more money to me than a decent passive system for the card + heat sinks for the ram + some fans to strap on to it...
but i would really recommend just replacing it. I lap heat sinks and cpu's but that simply looks like more work than its worth to do properly..

 

[OneMoar]

brazing or soldering with hot water copper pipe solder to fill the dents is probably the only way to actually be able to fix that properly.. But seriously, the amount of work that will need to go in to getting it done properly with the correct finish you would better spend on a good after market cooling system.
perhaps the 4-5 hours to do it well is worth more money to me than a decent passive system for the card + heat sinks for the ram + some fans to strap on to it...
but i would really recommend just replacing it. I lap heat sinks and cpu's but that simply looks like more work than its worth to do properly..

should't take that long to solder or braze fill it the reason I didn't mention brazing is that its probly too hot for the shoddy copper/nickle they use here
if you use a piece of glass todo your lapping with and the proper progression of grit then it should only take a hour start to finish

 

[Shambles1980]

i dunno. usually takes me 2-3 hours to do a cpu properly. and with that i can do long strokes..
to me that just looks like a tiny little nightmare surrounded by things that will make it difficult to get a perfectly level finish.
if it can be torn down more so the mountings aren't there then shouldn't take that long. but im not convinced lapping is the best course for this particular situation.

 

[OneMoar]

i dunno. usually takes me 2-3 hours to do a cpu properly. and with that i can do long strokes..
to me that just looks like a tiny little nightmare surrounded by things that will make it difficult to get a perfectly level finish.
if it can be torn down more so the mountings aren't there then shouldn't take that long. but im not convinced lapping is the best course for this particular situation.

I just use 400 > 800 > 1000 > 1200 > 1500 and then finally 2000 and my small orbital sander ofc I do the first and last few passes by hand it doesn't need to be perfect just better then it was

 

[Steevo]

Copper shim soldered to the heatsink, but that will be a pain, so just a shim of copper, with good TIM on both sides and clamp it tight, and re-tighten after a few hours of running it.

 

[OneMoar]

he could just RMA it tho there is a chance the cooler he gets back could have the same defect

 

[Shambles1980]

im thinking that they could possibly get away with using coollaboratory's liquid metalpad
Should be about $6 or so. and i THINK should be thick enough to fill the dent and make contact every where.. but they are pretty damned thin things.

 

[OneMoar]

im thinking that they could possibly get away with using coollaboratory's liquid metalpad
Should be about $6 or so. and i THINK should be thick enough to fill the dent and make contact every where.. but they are pretty damned thin things.

liquid metal is highly conductive I don't know if the r290 is open die or not

 

[Shambles1980]

copper is pretty darned conductive 2 lol...

 

[OneMoar]

copper is pretty darned conductive 2 lol...

yes but copper isn't a liquid also most lquid metals contain gallium and gallium will turn non-plated aluminum into something with the strength of wet cardboard overnight

nickel or copper plated is relatively immune depending on the quality of plating

 

[Sasqui]

See if you can get a thin copper shim from the hardware store instead of glass. Glass isn't the best idea since it can shatter as well as not being a very good with heat.

Indeed and I misread that I wanted a flat base for sanding, not for a thermal shim.

Here's my ingredients. The rubber cement was like dried snot, so I used carpenters glue instead.

First lap... you can still see the crater.

Second lap...

Third lap... huff huff... the crater is smaller.

Final lap. It feels like a marathon. This is with the last finest grit (400)

Doesn't look great but comparing to the original, it couldn't be any worse. I had some extra arctic 3 for a contact test, looked great.

Final results...

Playing FarCry 3, fan still is loud as hell at a cap of 85c in CCC, but it doesn't get over 81c.

Should I try MSI afterburner? Anything has to have a better fan profile than CCC, it sucks!

That's all I can say.

 

[OneMoar]

you need finer grit 400 isn't gonna cut it you need to go 400 > 800 > 1200 >2000 before you see results doesn't need to be mirror smooth but it should be shiny
if you take to much more off you may need to adjust the mounting screws to get proper contact

 

[Shambles1980]

that looks far from done.. but seeing as you have started. you should get something better than the wooden blocks imo.
and you need the paper to travel the whole length "left to right" of the part of the heat sink you want to lap. do that for a bit then turn the heat sink along its axis so your still working left to right, but now your working across the marks you did.

to be honest with you.. 400 grit is not good enough. even for an "it will do" job your looking at a MINIMUM 800 grit. and i wouldnt want to leave it like that either.

the problem your looking at now "IMO" is if you cant get it level enough you will end up with even less of the surface contacting the gpu than you did before. you dont want to sand it to a slight wedge, or have a slight mound in the middle.
this is why people reccomended you used glass or a copper shim as these things are very flat. but as you have to hold the paper and rub that against the heat sink, rather then hold the heat sink and rub it against the paper taped down to a flat surface.. Getting the correct finish could be a bit of a pain.
Honestly i dont see doing it that way as being any more effective than using a drum sander attachemnt on a dremill.
At least with the dremil you could try and make a jig of sorts to keep it level.

any way good luck with it.

 

[OneMoar]

that looks far from done.. but seeing as you have started. you should get something better than the wooden blocks imo.
and you need the paper to travel the whole length "left to right" of the part of the heat sink you want to lap. do that for a bit then turn the heat sink along its axis so your still working left to right, but now your working across the marks you did.

to be honest with you.. 400 grit is not good enough. even for an "it will do" job your looking at a MINIMUM 800 grit. and i wouldnt want to leave it like that either.

the problem your looking at now "IMO" is if you cant get it level enough you will end up with even less of the surface contacting the gpu than you did before. you dont want to sand it to a slight wedge, or have a slight mound in the middle.
this is why people reccomended you used glass or a copper shim as these things are very flat. but as you have to hold the paper and rub that against the heat sink, rather then hold the heat sink and rub it against the paper taped down to a flat surface.. Getting the correct finish could be a bit of a pain.
Honestly i dont see doing it that way as being any more effective than using a drum sander attachemnt on a dremill.
At least with the dremil you could try and make a jig of sorts to keep it level.

any way good luck with it.

I have a fixed mount for my dremal
and yea he bouched it pretty bad hes gonna need to go over that again with 800 then 1200 then 2000 if he wants it todo any good hes already at the point where it looks like he might need to replace the mounting studs with some shorter ones

 

[Vario]

The first pic might have been perfect if he had filled the hole first with the solder as above.
I don't see how you could take off material to get that depression level with the rest without the result he has now, the only solution was to add material.

A small disk sander might work, or a small orbital, I don't know if they come that small. On the cheap, maybe a wood circle bit with sand paper glued to its face, mount a drill in a vise and try to evenly apply pressure to the block?
http://www.cpooutlets.com/metabo-sx...bit-disc-sander/mtbn600405420,default,pd.html

The cost of acquiring new tools is better spent on a aftermarket heat sink.

 

[Shambles1980]

I don't like to say it, but i kinda knew this would be the end result..
Perhaps i should have been more assertive in my "i wouldn't do that my self" comments.

The dents really were to deep. and the limited accessibility of the actual contact area was always going to make it a difficult job to do right..
Im one of the cheapest people i know. I dont like to spend money.. but in all honesty in the long run would have been more cost effective to buy an after market cooler. or given it is a R9 290x even a second hand stock heat-sink and fan (there must be lots out there that were replaced day 1)

but seeing as its at this point already may be time to get serious with it.
get the blow torch out heat that sucker up and get the solder on there cover the whole face with a mill or so of solder as even as possible. and then start sanding it down again..
i dont see how you can get a good enough finish on it with where it is though. so to me it would be a waste of effort. so much more you can do with the time, there really isnt that much time to be had to fritter it away when the chances of achieving your goal is less than certain.

 

[OneMoar]

agree at this point if he wants sub 80c temps hes gonna need to fill it and start over thankfully solder is softer then copper and it will go much quicker
keep in mind that if you overheat the block you could cause permanent damage to the heat-pipes rendering the cooler useless