Lapping CPU with Sand Paper 600 and thinner ?

uteotw · 28-05-2004 1:21pm #1

Hi

I'm going to Lap my P4 as described in the following article.
http://www.overclockers.com/articles706/index02.asp

They used sandpaper 600, 1200, 2000, 3000 etc...

The thinner I could find in B&Q was 600.

Is it he same 600 as they describe in the article or is the 600 at B&Q thinner ?

Where can I find thinner than 600 around Dublin ?

Thanks
uteotw

BigEejit · 28-05-2004 1:49pm

I'd be interested in doing it as well ..... the top of my 2.4c is like a flippin soup bowl ... anyone know where to get that really fine sandpaper in Cork (and no "in any car spares shop loike" answers please, actual names of places please)

BabyEater · 28-05-2004 5:49pm

Is the heatspreader of the P4 not supposed to be curved as it will deform to a flat surface when the heatsink is mounted on it with the downward pressure.

uteotw · 28-05-2004 5:56pm

I think it is... but some people got from good to no result by lapping their CPU.
I've just received my Thermalright SP-94 heatsink, panaflo 92mm fan, Articsilver paste 5 and Enermax fan controller... I want the whole is meant to run really quiet even when I play so I want to max out heat transfer by reducing the heatspreader thickness.

So anyone to tell me where to buy super thin sandpaper ?

BabyEater · 28-05-2004 7:28pm

I got up to 1500 in a car parts shop any good one will ave it.

uteotw · 28-05-2004 8:15pm

Cool I'll check that tomorrow...
I'll post some update about the whole thing...

Sir Random · 28-05-2004 8:51pm

Take it down to the copper!

uteotw · 28-05-2004 10:34pm

that's the plan... is it yours ?

Sir Random · 28-05-2004 11:11pm

Yeah, it's a 2.4b (clocks to 3.2Ghz). The heatspreader was quite concave, so I had lots of copper showing by the time it was flat. Then I kept going to get the "all copper" look

Redrocket · 28-05-2004 11:25pm

go to a proper hardware store. car filler+panel+paint shops should sell every grit from 100 to 3000.
be interesting to see what the success rate is for people that lap their cpu

Redrocket · 28-05-2004 11:39pm

actually you might consider lapping your heatsink too. your trying to get cpu perfectly flat for more surface contact. so you might as well make sure that your heatsink is perfectly flat as well.

Matt Simis · 29-05-2004 10:48am

Yep, Motorway in Blanchardstown or Motorstore in Liffey Valley have a full range of grits. I think Ill lap the Athlon 64 2.2GHz Im getting in a few days..

Matt

uteotw · 29-05-2004 11:07am

thanks for the info everyone...
otherwise from searching the web it doesn't seem necessary to lap the heatsink... especially a good one. My Thermalright SP-94 has quite a good finish.

ZENER · 29-05-2004 5:43pm

Stoopid question, if you sand down to the copper how do you prevent it from oxidising and forming a coating ? Or am I missing something here ?

ZENER

uteotw · 29-05-2004 8:17pm

Don't know... never seen any coating on copper heatsink in all my years on PC.

I guess the limited direct exposure to air and the thermal paste slow down the process.

Anyway... I could only find 1200 grit sandpaper today !

I went to Stillorgan and Nutgrove shopping centers both Motorstore shops were shut down (completly emptied) !

Found the 1200 sandpaper in a bike shop in Stillorgan and the guy there said thinner than that would be hard to find.

Anyone with more precise leads as to where I can fine 1600 and thinner ?

Where's the motorstore in LiffeyValley I don't remember seeing one ?
What street is Motorway on in Blanchardstown ?

Thanks

Matt Simis · 29-05-2004 10:36pm

Originally posted by uteotw

Where's the motorstore in LiffeyValley I don't remember seeing one ?
What street is Motorway on in Blanchardstown ?

Thanks

Motorstore Liffey Valley is near PC World and B&Q. Motorstore are liquidating (and wont honor a EUR50 I have... grrr), hence the shutdowns.

Streets in Blanch...? Im referring to Blanchardstown Shopping Centre of course, not the Village

. Its in the West Retail Park, near KFC.

Matt

unkel · 29-05-2004 10:55pm

Originally posted by uteotw
Where's the motorstore in LiffeyValley I don't remember seeing one ?

It's not in the main centre, but in the retail centre just across the road from the cinema. There's a PCworld, curry's, atlantic, etc.

Redrocket · 31-05-2004 10:25pm

MotorStore have liquidated already as far as i know. I used to work there. They wouldnd have had the sandpaper you want anyways. Try a proper hardware store. And i mean PROPER. Not some crap retail outlet that will only sell money making crap ( sand paper is not a money maker )

Matt Simis · 01-06-2004 11:08am

Well, guess they vary, as the one in Liffey Valley is still open and operating under the terms of the liqudation and they sell the mentioned sandpaper (75c a pop)...

Regardless, Motorway have a better range of sandpaper and are still in the black.

Matt

SouperComputer · 02-06-2004 10:21pm

Originally posted by Matt Simis
Yep, Motorway in Blanchardstown or Motorstore in Liffey Valley have a full range of grits. I think Ill lap the Athlon 64 2.2GHz Im getting in a few days..

Matt

get back to us with how you get on. Im thinking of doing the same myself in conjunction with some nice silver paste.

uteotw · 02-06-2004 11:16pm

Still no success to get thinner grit than 1200...

MorotStore in LiffeyValley was opened but the guy I talked to was brain dead... I asked for grit smaller than 1200 and he was pointing at sandpaper with feckin' rocks on it ! Anyway... I checked the little choice they had and it was 1200 max...

I stop buy some small car shop in Donnybroke... same... 1200 is the thinnest they have.

I really want thinner than 1200... at least 2000.

Stevenk (or everyone else for that matter) could you point me to a "proper" hardware shop... because I've no clue where to find one.

Come one lads... I'll be able to make a full report on the project... pictures and temps before and after...etc...

Ta.

SouperComputer · 03-06-2004 9:52am

Dewells DIY on George's st should have 2000 and finer:

4781377 is their number

uteotw · 08-06-2004 12:40pm

Dewells DIY on George St only has no thinner than 600.
I've also checked 2 other hardware stores in town (Weirs an ????) and it's the same story.

Is there any "good" hardware store in this town ?

Does anyone know for sure where to find sandpaper thinner than 1200 ?
No more speculation please.

<rant>
This is the kinda things that get me frustrated with Ireland... you never find anything that is a bit out of the ordinary... and if you do... it's overpriced.
</rant>

Sir Random what sandpaper grit did you use ?

Dman_15 · 08-06-2004 12:53pm

http://cgi6.ebay.co.uk/ws/eBayISAPI.dll?ViewSellersOtherItems&userid=mark01283&include=0&since=-1&sort=3&rows=50

That guy has P2000 P4000 by the looks of it.

SouperComputer · 08-06-2004 2:35pm

Originally posted by uteotw
Dewells DIY on George St only has no thinner than 600.
I've also checked 2 other hardware stores in town (Weirs an ????) and it's the same story.

Is there any "good" hardware store in this town ?

Does anyone know for sure where to find sandpaper thinner than 1200 ?
No more speculation please.

<rant>
This is the kinda things that get me frustrated with Ireland... you never find anything that is a bit out of the ordinary... and if you do... it's overpriced.
</rant>

Sir Random what sandpaper grit did you use ?

when did you speak to them? If they dont have something in, usually they will get it for you

Sir Random · 08-06-2004 4:52pm

Originally posted by uteotw
Sir Random what sandpaper grit did you use ?

I just used up to 1200. Plenty of people settle for just 800.

uteotw · 08-06-2004 7:25pm

SouperComputer : I went on Saturday... I asked if 600 was the thinnest they had and where I could get thinner... they didn't offer to order anything.

Dman_15 : thanks for the lead but I only want 1 sheet.

Sir Random : OK... I might settle for 1200 but I'm worried by the picture you posted... these scratches still look deep to me.

Sir Random · 09-06-2004 3:37am

I hadn't polished it when that pic was taken, I rubbed it on a piece of flat wet steel to finish it off:

Those scratches were only visible with the flash, it felt perfectly smooth even before I polished it.

uteotw · 10-06-2004 3:29am

wow !
flat wet steel ? anything in particular ?

Sir Random · 10-06-2004 12:04pm

It's just a piece of steel I scavenged fom the floor of an engineering works.

I use it for lapping GPUs too.

uteotw · 11-06-2004 3:31am

okay dokay... I'll see what I can find.

I'll do it this weekend.

1. set up the new heatsink+fan+controller and get some temps...

2. finally get that cpu lapped install evertyhing back and get some temps again to see if it was all worth it.

Thanks everyone... I'll post the results when it's all done.

BabyEater · 11-06-2004 7:01pm

I wouldn't have thought steel would be a good surface for lapping as i work in a steel fabrication shop and steel is never flat it is usually curved in or out slightly. Unless that is bar stock for milling which would have finner tolerances than the stuff we use.
A good lapping surface is glass as it is nice and flat.

uteotw · 13-06-2004 12:04am

I plan to use a mirror with the sandpaper... I'll see what finish I get with the 1200 and if I need to do what Sir Random did or not with the piece of metal or not as I cannot find thinner than 1200.

Today I've installed the Thermalright SP-94 and the Panaflo 92mm fan and measure temps.

Machine Spec:
Soltek Qbic 3401
Intel P4 3.0ghz 800FSB
Mushkin 2 x 512MB DDR400 RAM
Radeon 9700 128MB
Maxtor 2 x 160GB S-ATA
Pioneer 107 DVD-RW
Lite-On 40125s CD-RW

So, it's small, powerful, it's cramed... just 1 PCI slot left available... might put a cheap pinnacle TV tuner/capture card.

CPU Temps with Stock Intel HSF and thermal pad.
BIOS Idle : Case = 44c CPU = 53c
MBM5 Idle : Case = 41c CPU = 48c
MBM5 Load: Case = 54c CPU = 68c

CPU Temps with Thermalright Heatsink + Panaflo 92mm fan + ArticSilver3 paste
The fan is sucking the air away instead of blowing on the heatsink.
BIOS Idle : Case = 35c CPU = 45c
MBM5 Idle : Case = 35c CPU = 42c
MBM5 Load: Case = 45c CPU = 55c

I'm pretty happy with these new temps... I'll see if I get some improvement after lapping the CPU.

Sir Random · 13-06-2004 12:40pm

Big improvement, but a 10c rise in your case temps under load indicates that you may need better airflow through the case. It seems like the heat isn't escaping the case, which will limit the SP-94s performance (cpu idle should really be low 30s). Is the 1st PCI slot free? It can help if your gfx card has room to breathe, and the slot below is open.

uteotw · 13-06-2004 1:29pm

The Soltek 3401 is a Small Form Factor case. It only has 1 PCI slot and 1 AGP slot and with 2 hdd and 2 optical drives the airflow is pretty limitited. But it's still one of the best design around.

SFFTech Review

It has air intakes at the bottom, on the sides but over all it's pretty limited. Then their is a dedicated hot air extractor + the PSU fan also extracts the air from the case. I'll post pictures so show how packed the wholthing is.

My Load tests involved reading a DV AVI from one disk, compressing to MPEG2, and writing the resulting file to the other HDD. So not only the CPU heats up but the HDD as well... overall I'm really pleased with the new temps.

Here is the forum post that lead me to by the the cooling gear.

Lapping CPU with Sand Paper 600 and thinner ?

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