# Making a liquid cooling heatsink.



## Olaf-Lampe (Feb 24, 2010)

I did a lot of watercooling when I was overclocking my PC.
The easiest way was using the original heatsink. 
Modify the cooling fins to build a maze and seal the whole thing with silicone rubber. I always used clear polycarbonate for the walls, just for the looks.
Here is a 12 year old system ( selfmade cooling block w poly-carb. ), still working and hasn't lost a drop of water. 
Using destillated water with coolant additive is a good idea. During upgrades I flooded my graphic card and even the cpu socket more than one time with no bad effects.

-Olaf


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## dexion (Aug 22, 2009)

Ive been thinking about doing this with my LS controller as well. 

Google liquid cold plates. This will give you a good idea of how it can be done. I even found several that will fit. The problem is the smallest run they will do is 25 pieces (at about 100 a piece dual channel.) So I havent come up with anything cheap. You could take 2 1 inch thick pieces and mill out channels from both gasket them together nipple them and be done with it. (Ala Jack's cooler.) I said the heck with it and added 2 more fans in parallel. I may get a 6x6 inch piece of allumimum heat sink and add it on to the front of the heat sink on the controller and add another 2 120mm fans. If you come up with something let me know. It all seemed like too much trouble for the gain (for my use its just a commuter to and from work not a drag car etc.) Carefull however the screws mounting the heatsink may be live (read that somewhere or other about the ls controllers thats why they cover them with goop I could be wrong however.)


Assuming they were live I was able to find a heat sink box that covered the whole controller top to bottom (sort of a heat sink cage) that then gave much more area to get rid of heat. Again it was cheaper and faster and easer (kiss) to add 2 more fans.

If you dont mind the noise (and want to try something before going through the hassle of water cooling the controller) (not too bad (noise) since they are in the engine compartment on my conversion I cant hear much in the car with the windows down, try these (i may ditch my 4 fans for 2 of these.)

http://www.coolerguys.com/840556021698.html


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## TX_Dj (Jul 25, 2008)

While water does have a specific heat capacity greater than air, steam does not. If there's any risk at all that your setup will "boil over" then you're better off with air.

A better heat sink, with larger fins and/or forced air induction may be cheaper and easier to maintain through the life of the vehicle.

A different material for the heat sink, such as copper, could be a better solution as well. Copper can conduct about twice as much heat as aluminum alloys, but weighs about three times as much and is about 4-6x more expensive. 

I'd venture a guess that if you build a carbon copy of the existing sink out of copper, you'd be done with any heat issues. Similarly, if you build another heat sink with aluminum at the same dimensions but with 1/2" fins, it'd be the end of the issue as well.

However, if you build a water cooling setup, and keep a water heat exchanger in the vehicle, you could reclaim that waste heat in the cabin, fwiw.

On the flip side of the discussion, because water has a higher specific heat capacity, it's much less efficient to use a water heater to provide heat to the vehicle cabin than it is a direct air heater element.


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## GerhardRP (Nov 17, 2009)

dexion said:


> Ive been thinking about doing this with my LS controller as well. <snip>
> So I havent come up with anything cheap. You could take 2 1 inch thick pieces and mill out channels from both gasket them together nipple them and be done with it. (Ala Jack's cooler.) <snip>


An easier way is to use a long drill to go almost through in two places, then almost through again in the perpendicular direction, crossing the bottoms of the first two holes. Plug the last hole and put nipples on the first two and you have a neat u-shaped channel. A three channel configuration would work too.
Gerhard


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## TomA (Mar 26, 2009)

Try a beverage dispenser cold plate. These are aluminum castings with embedded food-grade stainless tubing. The casting is connected upstream of a hand-held bar-style beverage dispenser, and goes into the bottom of the ice machine (or an ice chest outdoors) to cool the dispensed fluid. Pretty slick, and kinda just what you're looking for:

http://www.servu-online.com/Beer-Eq...oglebase&utm_medium=comparsionshopping&aff=15

This one is 10x15, but they are available 8x10, too.

I think it would be wise to mill or sand one side of this perfectly flat, but its a pretty simple thing and so long as you aren't pressurizing it too much, it should work fine. If you could get both sides flat, you could put a heat sink on the other side and have both liquid and air cooling backup. 

Here's a single pass one on ebay for $78:

http://cgi.ebay.com/Cold-Plate-sing...tem&pt=LH_DefaultDomain_0&hash=item5884b87669

I think its worth a try...

TomA


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## grayballs (Aug 27, 2008)

This was my answer,,, I'm using direct refrigeration to cool the units, but I suspect that water, glycol, alcohol, etc. would be acceptable. I wouldn't get too excited about the ability to recapture the heat for cabin usage,,, not much practical heat there,,, better to concentrate on removing it 

http://www.diyelectriccar.com/forums/showthread.php?t=31603


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## aeroscott (Jan 5, 2008)

TX_Dj said:


> While water does have a specific heat capacity greater than air, steam does not. If there's any risk at all that your setup will "boil over" then you're better off with air.
> 
> A better heat sink, with larger fins and/or forced air induction may be cheaper and easier to maintain through the life of the vehicle.
> 
> ...


 just looked up the specific heats for air and steam , looks like steam is about 2x better then air . to make steam it takes 3,400 watts / lbs. of water . I have some water cooled grid tie inverters . they just use a welded alum box with pipe nipples . No pump, gravity system , 2kw .


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## GerhardRP (Nov 17, 2009)

Common guys, if you have steam, your silicon divices are already fried.
water is a best coolant for this purpose.
Gerhard


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## JRP3 (Mar 7, 2008)

If you ever see below freezing temps you better have an antifreeze solution instead of just water.


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## bliksem (Aug 3, 2009)

Mcmaster Carr sells cold plates :

http://www.mcmaster.com/#cold-plates/=790jsy


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## JRP3 (Mar 7, 2008)

I saw those but they seem kind of small at 3.5 inches wide. Might be enough though.


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## etischer (Jun 16, 2008)

JRP3 said:


> I saw those but they seem kind of small at 3.5 inches wide. Might be enough though.


I'm using the 3.5" x 5" Mcmaster cold plate. I can pull 60kw from the battery for about 2 minutes before going into thermal shutdown. It's just enough to keep me at 60mph up my long 6% grade. Under normal heavy foot driving conditions, cooling has never been an issue for me, and I'm pushing 4200 lbs/ 80kw.


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## aeroscott (Jan 5, 2008)

I think I screwed up my math , 3.4 btu = 1 watt not the other way around as per my last post . But water is what is used by all the high end systems . A over heated 212 deg. F temp system is well below what the igbts can handle . I like the copper box / heat exchanger for a maxed out system .added , copper plate with silver soldered copper tubes , very simple silver can't be beat .


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## Jimdear2 (Oct 12, 2008)

Has anyone ever tried taking a finned heat sink and wraping suitable sized copper tubing into some of the fins, maybe gluing the tubing in with a suitable metal based epoxy like Devcon or JBweld. Then run coolant through the tubing to a radiator.

Seems like you would have the best of both worlds. I always planned to do that if I needed liquid cooling.

Jim


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## JRP3 (Mar 7, 2008)

Jimdear2 said:


> Has anyone ever tried taking a finned heat sink and wraping suitable sized copper tubing into some of the fins, maybe gluing the tubing in with a suitable metal based epoxy like Devcon or JBweld. Then run coolant through the tubing to a radiator.


That's a pretty good idea. Ideally you'd get tubing that would press fit in between the fins for good contact so you didn't have to use much epoxy, which wouldn't transfer heat well.


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## Woodsmith (Jun 5, 2008)

Jimdear2 said:


> Has anyone ever tried taking a finned heat sink and wraping suitable sized copper tubing into some of the fins, maybe gluing the tubing in with a suitable metal based epoxy like Devcon or JBweld. Then run coolant through the tubing to a radiator.
> 
> Seems like you would have the best of both worlds. I always planned to do that if I needed liquid cooling.
> 
> Jim


Would it not be easier to build the heatsink into a water proof box and then just pump water over the fins?


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## voltmatic automaton (Nov 2, 2008)

I want to thank everyone for their enthusiastic and inventive responses. There are some genuine gems of ideas here. Keep them coming if you can. The cold plate idea seems like a really reasonable way to go, and i intend to get a tall finned heatsink,

so thanks again everyone,


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## JRP3 (Mar 7, 2008)

Woodsmith said:


> Would it not be easier to build the heatsink into a water proof box and then just pump water over the fins?


That doesn't sound easier to me compared to winding some tubing in between some fins.


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## tc.burns (Jan 2, 2010)

While I am waiting for my LS controller to come back from the factory, I would like to build a water cooling system for it. I just picked up some aluminum plates and am getting ready to drill holes and tap the ends to mount pipe barbs. Without the controller in hand I don't know what the dimensions are of both the top heatsink and the bottom of the case. 

Could someone provide me those measurements? Also, I am not sure if I should replace the existing top mounted heatsink with my new water plate. I could just use heat sink compound and clamp to the existing heat sink. Any comments?

Thanks!


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## Snakub (Sep 8, 2008)

I already beat you guys to press fitting tubing into an aluminum heat sink. No epoxy needed!


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## Anaerin (Feb 4, 2009)

The trouble with "Press fitting tubing into fins" like this is that you are beholden to the heat transfer capacity of the tubing material itself. In this case, PVC tubing, which is almost an insulator.

Why not get something like this:

http://www.ncix.com/products/index.php?sku=21447&vpn=DD525HD2&manufacture=Danger Den

That's 2 blocks that you could place side-by-side. Then a 12vDC Pump (http://www.ncix.com/products/index.php?sku=19862&vpn=MCP655&manufacture=Swiftech) and radiator (http://www.ncix.com/products/index.php?sku=41915&vpn=5060207430043&manufacture=Thermochill) and you have yourself a complete cooling system. Heck, you could use multiple radiators, or even the car's original rad if you thought you needed the capacity.


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## Snakub (Sep 8, 2008)

Does that look like PVC to you. Can you bend PVC like that? NO!!! Its steel brake line it cost 7 bucks. I already have a radiator and 12 volt mr. gasket fuel pump.Look at the prices of the products you recommend you must work for NCIX. I got all the rest of my parts out of a junkyard for free and also anyone in need of a throttle pot should consider throttle position sensors they have a built in spring and everything! Now the hottest my controller gets is 102 F. One time I got off the highway and it was just 84 degrees.


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## jehan12413 (Feb 4, 2010)

Instead of trying to put tubing between the fins I would mount an aluminum cooling block between the heatsink and controller. You might not even need the heatsink with sufficient coolant flow. The last one I built only had two coolant passages 3/8" dia spaced 4" apart the length of the controller and cooled so well it was slightly warm to the toutch.


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## tc.burns (Jan 2, 2010)

jehan12413 said:


> The last one I built only had two coolant passages 3/8" dia spaced 4" apart the length of the controller and cooled so well it was slightly warm to the touch.


Thanks jehan12413 for the info... That's the direction I have been thinking as well. I purchased some plate aluminum from a scrap vendor and am getting ready to start drilling some holes. I purchased both a 1/2" and 5/8" plate - not sure which one to use. How thick is the plate you used? I was thinking I would need to have the passages 1 - 2" apart so I am surprised that you could get by with only 2 at 4" apart. Did you do hook the two passages together as a single pass (series) or in parallel? Originally I was thinking of drilling mine cross ways (7" is easier to drill straight than 12"), and having 6 passages about 1" apart. But based on your comments - perhaps I could get by with fewer passages. I am also wondering if 3/8" passages in the 5/8" plate is better than 1/4" passages in the 1/2" plate. 

Also, what type of pump did you use and what is the flow rate?


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## JRP3 (Mar 7, 2008)

jehan12413 said:


> Instead of trying to put tubing between the fins I would mount an aluminum cooling block between the heatsink and controller.


Heatsink and tubing sounds a lot easier and cheaper.


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## jehan12413 (Feb 4, 2010)

Sorry I didn't post sooner, I was in canada with no computer. I used 1" plate because that was the size I had on hand and the passes are in series. As far as the pump I have tried several starting with a simple windshield washer pump for the first plate built. It worked fine on a curtis controller at 72 volts and 1200 amp as there was not enough heat generated to require it to run continuously. Now that I have switched from lead acid and have increased the voltage twards 200V I will be trying an electric fuel pump as there will probably be much more heat generated. As far as the flow rate I don't have any numbers available right now.


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## ngrimm (Oct 19, 2007)

When running water/alcohol injection on turbocharged cars, I have used Shurflo brand pumps with good results. They cost about $50. Seems like they would work. I tried fuel pumps but they didn't last long pumping water.


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## jehan12413 (Feb 4, 2010)

Thanks I'll have to give one a try. I just ordered a couple of cheap pumps on ebay which are good for diesel,gas or alcohol. I was thinking that with the antifreze there might be enough lubrication for the pump. Guess I'll see what happens.


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## tc.burns (Jan 2, 2010)

Regarding a pump... I am trying to decide between the following two Shurflo pumps:

http://www.northerntool.com/shop/tools/product_9414_9414 - 1.8GPM

http://www.northerntool.com/shop/tools/product_357081_357081 - 1.0 GPM

There are also a number of them with higher flow rates - but I don't think I need to go much higher - do I?

Comments?


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## ngrimm (Oct 19, 2007)

I think the flow rates are stated at max pressure which would be over 40 psi so I think either of them will more than keep up since I doubt you would ever see more than a few pounds. They also have a screw you can turn to reduce pressure if you need to. Norm


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## JRP3 (Mar 7, 2008)

I'd say they are both overkill since you don't need much pressure. I'm using this one in my heater core system:
http://www.adventurerv.net/shurflo-nautilus-single-station-water-pump-gpm-p-1713.html
http://store.solar-electric.com/100-00-21.html
Low pressure, low volume circulator pump.


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## grayballs (Aug 27, 2008)

JRP3 said:


> I'd say they are both overkill since you don't need much pressure..


I agree,,,, 1 gpm through a 3/8 tube would be north of 200'/min.,,,, my opinion,,,,,, noisey,,,, serious pressure drop, and more than you need. When I did mine (search "Coldplate") I started out with the idea to get as much heat as I could. Even with the twin controllers, no problem,,,, it's just not that much heat.


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## aeroscott (Jan 5, 2008)

I would use a Mercedes benz or BMW heater pump from 1994 or newer will have a magnetic coupling (no seal ) . heater size hoses , 2-3 gpm , 2 -3 amps , 12 volts nominal .very quite . $10.00 - 20.00 at pick and pull , New over 150.00 . PS much smaller then the sure flows


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## jehan12413 (Feb 4, 2010)

tc.burns said:


> Thanks jehan12413 for the info... That's the direction I have been thinking as well. I purchased some plate aluminum from a scrap vendor and am getting ready to start drilling some holes. I purchased both a 1/2" and 5/8" plate - not sure which one to use. How thick is the plate you used? I was thinking I would need to have the passages 1 - 2" apart so I am surprised that you could get by with only 2 at 4" apart. Did you do hook the two passages together as a single pass (series) or in parallel? Originally I was thinking of drilling mine cross ways (7" is easier to drill straight than 12"), and having 6 passages about 1" apart. But based on your comments - perhaps I could get by with fewer passages. I am also wondering if 3/8" passages in the 5/8" plate is better than 1/4" passages in the 1/2" plate.
> 
> Also, what type of pump did you use and what is the flow rate?


 Here is a picture of an old one I made for a curtis controller.


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## aeroscott (Jan 5, 2008)

aeroscott said:


> I would use a Mercedes benz or BMW heater pump from 1994 or newer will have a magnetic coupling (no seal ) . heater size hoses , 2-3 gpm , 2 -3 amps , 12 volts nominal .very quite . $10.00 - 20.00 at pick and pull , New over 150.00 . PS much smaller then the sure flows


 the amp draw should be no higher then 1 amp if more it's dragging


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