A story:
Had a friend that bottom painted his boat. I showed up just as he had finished the job and found he had painted his out drive with that copper based bottom paint. I told him he needed to remove the paint and use on recommended for aluminum. So sure that it wouldn't make a difference he told me he would leave it on and use the boat.
After a couple of days in the salt parts of his out-drive had holes in them. you guessed it galvanic corrosion. The aluminum acted as the anode and the copper was unaffected. Forget the heat sink grease if you fail to put an electrical insulator between the two surfaces. Heat sink grease has metal particles like silver in it to help transfer the heat. It is better to use similar metals. This should not be a problem as aluminum has a good record in heat transfer capabilities. In fact aluminum is almost a match to copper when used as a heat sink or conductor of electricity. The major problem with it is expansion that is not a factor when in contact with water. Can't remember the composition for marine use aluminum. As I recall copper that is used for a stronger alloy is not part of the mix.
Kevin Pemberton
On 12/03/2011 04:58 AM, Mike wrote:
Yes, be careful. Dissimilar metals in a water environment especially salt water can be asking for trouble. This problem was minimized on diesel engines like my old Westerbeke by having a sacrificial zinc inserted in the heat exchanger where a copper was used. Which was another item to maintain. Though heat transfer grease mentioned should solve that problem by isolating the metals from each other. I would just make sure they stay isolated. If they start to touch a leak could develop and that could ruin your day.Capt. Mike
From: Tom <boat_works@yahoo.com>
To: electricboats@yahoogroups.com
Sent: Friday, December 2, 2011 5:15 PM
Subject: Re: [Electric Boats] Cooling motors
Any concerns about bolting copper directly to aluminum?
Many years ago I had a bronze (copper alloy) clevis pin in an aluminum boom. The boom eroded around the pin in a few years.
Perhaps the alloys involved in this application are more compatible.
-Tom
--- In electricboats@yahoogroups.com, "Eric" <ewdysar@...> wrote:
>
> Hi Bill,
>
> You should contact James at Propusion Marine in Santa Barbara. He has designed, built and improved a "bolt on" water cooling adapter for the ME09xx motors. He has produced a unit that has shown consistant documentable results.
>
> Of course, you can take the time and money to fabricate your own version of his system, but then I would expect that your results may vary....
>
> Fair winds,
> Eric
> Marina del Rey, CA
>
> --- In electricboats@yahoogroups.com, Bill Heintz <bheintz@> wrote:
> >
> > I have a Motenergy ME0907 (x Mars Electric ME0201013001) PMAC motor 48v that I would like to Water Cool.
> >
> > Does anyone cave any experience with that? Photos?
> >
> > Initially I thought a coil of thermally conductive plastic tubing wrapped around the stator might work. But then I worried about the lines sweating condensate on to the stator . . .
> >
> > Since I'm not great at re-inventing the wheel, I thought I should ask the experts here first. :)
> >
> > Thanks
> >
> > Bill
> >
>
No comments:
Post a Comment