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Author Topic: Water cooling coil  (Read 2598 times)

J.beazley

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Water cooling coil
« on: July 18, 2007, 08:08:41 PM »

Just out of interest i need to water cool a 380 size motor and was wondering what people use around the motors???

ive got plenty of silicone hose left over from plumbing the fish tank with air pumps so i could use this to plumb it in.

any ideas of what to use???

Jay
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dougal99

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Re: Water cooling coil
« Reply #1 on: July 18, 2007, 08:25:11 PM »

all the ones I've seen were made from aluminium tube.

HTH

Doug
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J.beazley

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Re: Water cooling coil
« Reply #2 on: July 19, 2007, 08:03:44 AM »

Does anyone think i could get away with just using silicone tube wrapped round the motor can???

Or would the heat melt the silicone???

Jay
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DickyD

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Re: Water cooling coil
« Reply #3 on: July 19, 2007, 08:07:07 AM »

I wouldn't think so Jay as you would not get the heat tranference with the silicone that you get with aluminium.
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Shipmate60

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Re: Water cooling coil
« Reply #4 on: July 19, 2007, 09:58:43 AM »

Jay,
Silicone tube will work of a fashion but will tend to cool the air around the motor not the can, and not very well at all.
What in effect you are trying to make is a heat exchanger where the heat from the motor flows into the WATER in the cooling coils.
Silicone  doesn't transfer heat readily so the exchange of heat is very inefficient.
Brass, copper and aluminium being a metal have a far greater ability to transfer heat (thermal efficiency) so are far more efficient.
It is rather like putting a towel over you home radiators, they will still work, but take much longer to work effectively.
If the motor is getting hot you want to remove as much heat as possible as that is dependant on the water flow through the pipework and the transfer rate through the pipe walls.
You can get ready made aluminium cooling coils for 3 series motors off eBay for less than a fiver.
Hope this helps.

Bob
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kendalboatsman

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Re: Water cooling coil
« Reply #5 on: July 19, 2007, 10:06:18 AM »

Hi Jay,

Howes models sell them for 3.99. http://www.howesmodels.co.uk/RadioControl/viewProducts.php?SubCatID=111

No link with them other than a satisfied customer, I bought my windstar sails from them. And looking at their motor prices I will be placing an order at the weekend.  :)

Clive :)
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Bunkerbarge

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Re: Water cooling coil
« Reply #6 on: July 19, 2007, 10:23:43 AM »

There is a very real danger using silicone that you will effectively insulate the motor and make things considerably worse. 

The tube must be of a material with good heat transfer properties that will allow the heat to transfer quickly from the motor casing, through the tube and be carried away by the water.

All heat exchangers found on real ships will be made of such materials as cupro-nickel or bronze for these very reasons.

One of the easiest materials to make one from yourself would be copper pipe but you would need to anneal it first and probably regularly during the manufacture.  You would get the best contact though and the most efficient cooling.

A ready manufactured aluminium one os probably the safest bet but you must ensure a good contact between the motor casing and the coil.  If the fit is slack you will have an air gap that will act as an insulator and once again heat transfer will be reduced.
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J.beazley

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Re: Water cooling coil
« Reply #7 on: July 19, 2007, 12:34:02 PM »

Cheers for the helpful advice guys,

Its not that the motor gets all that hot its the fact i have room in the hull to water cool the 380 size motor, in case your all wondering its going in the tamar thus why i want to plumb them out the transom to give the look of exhaust (well sort of).

do you think i could coil the one from howes smaller without it damaging the OD or ID of the pipe???

Jay
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Stavros

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Re: Water cooling coil
« Reply #8 on: July 19, 2007, 10:17:27 PM »

Cheap and cheerfull way of manufactering a cooling coil go down to your local partco car parts supplier and buy a coil of 4.5mm COPPER brake pipe wrap around the can and hey presto one cooling coil.Stavros
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HS93 (RIP)

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Re: Water cooling coil
« Reply #9 on: July 20, 2007, 12:28:52 AM »

If you are going to do the above use a tube about a 1/4" of an inch smaller than the motor so that when it goes on it is very tight.

Peter
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