Cardboard ducting - Safe?

Cooling Processors quietly

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BenW
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Cardboard ducting - Safe?

Post by BenW » Tue Jun 21, 2005 4:58 am

Just made a cardboard duct....was bored! Well it works and it works very well! Case fan is at 7v and temp in the warmer UK weather today is 29C whilst im using it so a bit more than idle temps. CPU is a 2.26Ghz P4 which draws 67.6W apparently.

So what i really want to know is, are cardboard ducts safe when cpu temps get high as in about 50C. Is there any chance of fire?

swivelguy2
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Post by swivelguy2 » Tue Jun 21, 2005 5:18 am

Paper will certainly not ignite on its own at under 150 C.

So the only way it could catch fire is if something in your computer makes sparks. Which I doubt anything does.

chylld
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Post by chylld » Tue Jun 21, 2005 5:23 am

it'll be perfectly safe. imagine trying to set a piece of cardboard alight by finding the hottest parts inside your computer :)

BenW
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Post by BenW » Tue Jun 21, 2005 7:41 am

Thats what i needed to hear

Thanks, cant believe how much difference it makes!

dentaku
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Post by dentaku » Tue Jun 21, 2005 8:05 am

BenW wrote:Thats what i needed to hear

Thanks, cant believe how much difference it makes!
Can you show us a picture of what you've done?

BenW
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Post by BenW » Tue Jun 21, 2005 8:06 am

Not got a camera to hand. I'll try and get a pic sometime. Its basically an L shape going from rear case fan to the top of the XP120. Nothing special

Ducky
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Post by Ducky » Tue Jun 21, 2005 8:46 am

Depending on the type of duct and type of cardboard, the heat might make the cardboard "floppy" and make the duct deform. So, some duct tape to maintain its rigidity may be necessary.

(I was using tissue boxes to make a L-shaped piece for a VGA card duct, much as Bluefront and Arctic cooling had done.)

rtsai
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Post by rtsai » Tue Jun 21, 2005 3:53 pm

BenW wrote:Not got a camera to hand. I'll try and get a pic sometime. Its basically an L shape going from rear case fan to the top of the XP120. Nothing special
So your XP-120 has no fan of its own?

pangit
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Post by pangit » Tue Jun 21, 2005 5:09 pm

BenW wrote:Thats what i needed to hear

Thanks, cant believe how much difference it makes!
Great! 8) I've used ducts for over 5 years in my systems wherever practical, as they can make a massive difference to temperatures.

And I've always used cardboard (from cereal packets usually! :shock: ) with no problems. You'd burn out just about every component in your PC before the cardboard caught fire! And I don't even know how you'd get it that hot without doing something stupid like pumping 500V into the PSU! :?

But as Ducky says secure it with some duct tape to keep it in place and to prevent it warping.

Bluefront
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Post by Bluefront » Wed Jun 22, 2005 5:13 am

Well I wouldn't use cardboard in any computer project.....even as a temporary test. It won't catch fire, but there are better materials to use.

I use flat pieces of soft plastic......such as a "for sale" sign from a hardware store. They are much more durable, can bend without creasing, can be "duct taped" over and over, and can form a permanent part of your setup.

Plus you might not be accused of a ghetto mod.... :lol:

IsaacKuo
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Post by IsaacKuo » Wed Jun 22, 2005 6:27 am

I never shy away from cardboard or "ghetto-mods", but I do tend to use clear plastic rather than cardboard most of the time. There's less fabrication effort since I can usually find suitable shapes to start from, it looks cooler, and it's a LOT easier to see where to punch the mounting holes.

BenW
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Post by BenW » Fri Jun 24, 2005 1:46 am

rtsai wrote:
BenW wrote:Not got a camera to hand. I'll try and get a pic sometime. Its basically an L shape going from rear case fan to the top of the XP120. Nothing special
So your XP-120 has no fan of its own?
Thats right :)

Glad cardboard should be ok

BenW
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Post by BenW » Fri Jul 01, 2005 4:04 pm

dentaku wrote:
BenW wrote:Thats what i needed to hear

Thanks, cant believe how much difference it makes!
Can you show us a picture of what you've done?
Well as promised i just took some pics, chance to test out the camera on my lovely new K750i. All pics taken in a pitch black room with night mode and flash on phone. Macro mode on

Overall pic:
Image

Gap between GPU and duct. Half the northbridge heatsink is in the duct:
Image

Gap between PSU and heatsink/duct:
Image
Last edited by BenW on Sat Jul 02, 2005 1:01 am, edited 1 time in total.

Bluefront
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Post by Bluefront » Fri Jul 01, 2005 5:04 pm

Darn man.....have some pity for us dial-up users. You should adjust your image size to about 50kb. It'll look just fine on a monitor......plus will load much quicker.

BTW...your pictures are still loading for me. :cry:

CGameProgrammer
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Post by CGameProgrammer » Fri Jul 01, 2005 6:21 pm

My horizontal screen resolution is 1680 pixels and the images are even wider than that, causing me to have to scroll right to see not just the images but the comments here as well. So, yeah, either resize them or use smaller thumbnails linking to the images.

BenW
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Post by BenW » Sat Jul 02, 2005 1:02 am

Sorry, was really tired when i posted them.

Resized now

G7MJV
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Post by G7MJV » Sat Jul 02, 2005 4:29 am

That looks good to me.. ls the fan sucking or blowing ?

BenW
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Post by BenW » Sun Jul 03, 2005 7:57 am

sucking off heatsink and blowing out the back

Steve_Y
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Post by Steve_Y » Sun Jul 10, 2005 5:17 pm

I've always been a little reluctant to put anything cardboard inside my case, but I've come to realise that it's a silly thing to worry about. I doubt any component inside my PC would still be functioning by the time it was hot enough to burn cardboard.

I've just chucked together a simple cereal box & sticky tape duct to direct air from a case fan (92mm Nexus @ 7v) to a passively cooled 600Mhz PIII. It was already running at a perfectly acceptable temperature (under <50C at full load on a hot day), but the duct has reduced CPU temperature by around 7-8C. It means that I could upgrade to a faster CPU (maybe even a 1Ghz PIII?) and still have acceptable temperatures. I'd be happy with that level of temperature reduction if I'd achieved it by paying for a fancy heat sink, not bad for less than 10 minutes work.

BenW
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Post by BenW » Mon Jul 11, 2005 7:53 am

Steve, you can go better than a PIII 1Ghz.

I'm running a 2.26Ghz P4 and its about 50C load on a hot day. Soon i'll be making a switch so i switch between 5V and 12V on the fans easliy. Means i can have quiet fans when the pc is idling and lots of airflow when its needed.

CGameProgrammer
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Post by CGameProgrammer » Mon Jul 11, 2005 8:20 am

The Pentium 4 is an inefficiently hot chip, not suited for passive cooling.

BenW
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Post by BenW » Tue Jul 12, 2005 2:52 am

The new ones are, mine is an older Northwood with a lower FSB of 533. Means i get reasonable speed but its still cool. Also undervolted well.

Lowest i've seen it is 27C at stock speed but undervolted. Was in a UK summer night with ambient of about 20C i would guess

Bluefront
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Post by Bluefront » Tue Jul 12, 2005 3:24 am

Let me add another 2c. There are better materials to use than cardboard. Straight cardboard has a relatively stiff, hard surface......perfect for noise reflection. When I build ducts now-days, I use soft, bendable plastic materials.......but I cover all surfaces with sticky-back felt material. It has the ability to absorb some sound and quiets the airflow.

You could cover cardboard with the felt also. Felt around the edges can comform to irregular surfaces.....and seals much better than a cardboard or plastic edge.

Any flat surface in your case can reflect sound, and can be quieted with a felt or foam covering.....easy/cheap to do.

BenW
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Post by BenW » Tue Aug 23, 2005 5:43 am

Well, its a warm day so i decided to find out just how well the duct works.

Side panel on, duct in place - idle = 32C
Side panel off, duct off - idle = 50C!!!!

Speedfan screenshot to show what happens when i put the duct/side panel back on:

Image

I promise that high temp is idle (Just browsing the web, 2 windows open and winamp playing)

Sorry, bluefront...just read that. Whilst foam may quieten it, i dont think the pc is anywhere near quiet enough to notice a difference.

BenW
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Post by BenW » Tue Aug 23, 2005 3:13 pm

Just had a though. How about putting a curved piece of paper inside the duct, should help direct the airflow and stop it getting caught in the duct

Before

Code: Select all

         CPU
Rear Fan __|
After

Code: Select all

         CPU
Rear Fan __/|

BrianE
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Post by BrianE » Tue Aug 23, 2005 4:52 pm

I don't see why you can't try it, as long as at no point in the duct the overall cross-sectional area becomes restrictive. Like if you did this (exaggerated) it'd be bad:

Code: Select all

                |      |
----------------|     /|
F                   /  |
A                 /    |
N               /      |
-----------------------|

BenW
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Post by BenW » Wed Aug 24, 2005 4:41 am

Yea, was just thinking of slightly curving the corner. Nothing drastic.

Might try it now

For my own note, CPU Idle temp now = 32C

BenW
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Post by BenW » Wed Aug 24, 2005 6:09 am

Just put the paper in and temps have dropped 1-2C. Idles at between 30 and 31C now :)

quizzicus
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Post by quizzicus » Wed Aug 24, 2005 9:24 am

Yeah, as long as the operating temperature of your CPU stays below 233C (which might rule out Prescotts), you aren't setting anything on fire. :lol:

sundevil_1997
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Post by sundevil_1997 » Wed Aug 24, 2005 9:34 am

IsaacKuo wrote:I never shy away from cardboard or "ghetto-mods", but I do tend to use clear plastic rather than cardboard most of the time. There's less fabrication effort since I can usually find suitable shapes to start from, it looks cooler, and it's a LOT easier to see where to punch the mounting holes.
Hehe....you speak the truth, Isaac. I've come to regard you as the ghetto-mod guy. :lol: I have no fears of those either, since I have no pretty windows in any of my cases and would rather have something that works, than something that's pretty.

however, the time may be coming soon when one of my PC's DOES have a window. Where do you get clear plastic from? Does it come in sheets, or are you talking the odd clear-plastic candy container cut to fit the need? I've been to the local craft store and couldn't find any clear plastic. I'd really like something clear, but with a bit of color, so ducts will be something nice to see in a windowed-PC.

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