My new WB has a scratch, what to do?

Chief_Wiggum · Feb 6, 2003

Hi all,

Just received my new D-Tek TC-4 waterblock yesterday. To my dismay, it has a small, but somewhat deep scratch right where the cpu would make contact.

I normally would send it back, but I waited a week to get it. I'm tempted to just try and lap it out. Do you think I'll be able to, and will it make a big difference anyway?

Wangster · Feb 6, 2003

If you're comfortable with lapping then by all means.

A mirror finish would have been what one would strive for is it not?

Although I'm sure BillA has some pointed thoughts to make on this subject

I hope he doesn't chew me out for that remark.

SkiFletch · Feb 6, 2003

it wont make a huge difference but just lap it out. lapping is much easier than it seems and I do it to all my cooling devices anyway

Chief_Wiggum · Feb 6, 2003

What grits do I start and finish with, any idea?

Wangster · Feb 6, 2003

I've heard:

start 400 and go up to more than 1600.

I know people have gone up to 2000 for mirror finishes.

UnLoadeD · Feb 6, 2003

I think a bad lapping job can do more harm than good. You are actually going for flatness versus smoothness. Judging by your questions, you have no experience with lapping. If I were you I would contact dtek and see if they will work something out with you. If you lap it and aren't happy with the results, I doubt they will exchange it. They might let you try it as is, and if you aren't satisfied, then exchange it for you. To me that would be the ideal arrangment to make. I've bought from them but never dealt with any customer service issues. I hear they are really good in that area though. Let us know what ya decide and how it works out for ya. One thing I would be curious to know from somebody with more knowledge on the subject is how much a scratch like that would really effect performance, assuming thermal compound is properly applied. Hopefully somebody will enlighten us.

peace.
unloaded

Chief_Wiggum · Feb 6, 2003

That was why I wasn't too thrilled about lapping it. I can't guarentee a perfectly _flat_ surface. At the same time, after spending a lot of time and money trying to get my WC setup together, I want to make sure everything is perfect. I'll let you know what happens.

nikhsub1 · Feb 6, 2003

The key to lapping is finding a FLAT surface to actually lap on. I have a huge heavy granite table which is pretty flat. If you do lap it, I would start with like 200 grit, get the scratch out, then go to 400 then to 600. I would not (and I don't) lap to any higher than 600 grit. A scap piece of marble or granite is good for lapping, as is a thick glass table. No one can ever get it perfectly flat, but if you take your time and find a good surface, I'm sure you will have success. Another tip is to take a sharpie and draw lines all over the bottom before you lap. when you start, look at the lines, this will show you if the block was flat if they all come off evenly. My TC-4 was VERY concave in the center - my lap job yeilded me about 2C or so. Bottom line is that block NEEDS to be lapped or exchanged, I would not use it with that huge scratch right over the core.

Chief_Wiggum · Feb 6, 2003

Good tips, I have some thick tempered glass shelves I could use. I email dtek about it, I'll see what they say.

If what you're saying is true, the replacement block may be concave and require lapping anyway.

Why not any higher than 600 grit?

slater3333uk · Feb 6, 2003

well the whole point of lapping is to get a perfectly flat and uniform surface

imho the only way to lap something properly is with a surface plate (thats a ground steel plate for anyone who dose not know) these are perfectly flat so if you use them properly then your w-block should en up perfectly flat too. i hear about people who just use there work bench but this is just defets the object of lapping. and also GLASS IS NOT FLAT! it may be smooth but not flat

remember

you are looking for a flat surface not a smooth surface this is the most common misconception when it comes to lapping

Wangster · Feb 6, 2003

Hmm,

That is a very good point about a smooth surface not necessarily being flat.

Where does one acquire these perfectly flat steel plates?

SkiFletch · Feb 6, 2003

yeah, go from 200 to 600. any more than that is pretty worthless and just for show

undertow · Feb 6, 2003

glass = flat

NeoMoses · Feb 6, 2003

undertow said:
glass = flat

Not all glass is flat. Some glass is ground flat, much like a steel surface plate. Also, you can purchase granite plates that are guaranteed flat to within 0.0001" (yes, 1/10,000 of an inch) over the entire surface.

Nothing is "perfectly flat," it but surfaces may be "flat enough" for the job at hand. You can get reasonable flatness if you lap your blocks on a standard piece of glass. Not perfect, but usually pretty good.

Wangster · Feb 6, 2003

NeoMoses,

Could you tell us where to acquire these flat steel/granite plates?

Thanks,

Wangster

[EG]~NaTz~ · Feb 6, 2003

yes neomoses i havent heard of this yet or even if u dont know a dealer how much are thay i am interested.

bigben2k · Feb 6, 2003

Glass isn't always flat, that's true, but it is relatively easy to determine how flat it is, by looking at the reflection.

Flat is indeed more important than "shiny". I agree with Nickhsub1: start with 200 (actually 220 is common), then 400, then 600. That's a pretty big gouge you've got there. It may look small, but you have to remember that to fix it, you basically have to sand off all the copper around it. Sanding that much copper may/will take a very long time, so start with 220, keep going until you can't see that gouge, then goto 400, and so on...

Lap in one direction only, and do not turn the block: this will give you a flat surface (as much as is possible, from home), as lapped as it needs to be.

Good luck!

DodgeViper · Feb 6, 2003

Boy it’s good to be home from the hospital, although I feel like SH**. Anyways this is what I use to lap with. It's 2" thick of granite with a surface that was ground to 0.0001. Being 2" thick it’s stable and heavy.

nikhsub1 · Feb 6, 2003

DodgeViper said:
Boy it’s good to be home from the hospital, although I feel like SH**. Anyways this is what I use to lap with. It's 2" thick of granite with a surface that was ground to 0.0001. Being 2" thick it’s stable and heavy.

That's exactly what my coffee table is made of, and very flat, it must weigh 1500 lbs. Anyway, Dodge why were you in the hospital? You OK? You are always hurting yourself! You need to slow down!

DodgeViper · Feb 6, 2003

Nikhsub1, On Wednesday of last week an accelerated infection in my neck caused swelling so severe that by Friday had cut off my air way in my neck and I could not breathe. Doctors still do not have a clue what brought on the infection. On Sunday they drained 32cc of fluid from my neck. I looked like elephant man.

My new WB has a scratch, what to do?

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