Aluminum vs copper buss bar

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Aluminum vs copper buss bar

David D. Nelson
I'm adding a PakTrakr current sensor to my Gizmo and
need to use a buss bar. I've made one out of 1/4"
aluminum but I'm wondering about the issue of
corrosion and resistence. The battery box on a Gizmo
is not completely protected from moisture. Wind blows
right over the top of the batteries and in wet weather
it is common to have a layer of moisture on them.
Should I go with a copper buss bar instead? If so,
where can I get some copper bar stock since I can only
find steel and aluminum?

Thank you,


David D. Nelson
[hidden email]

http://www.austinev.org/evalbum/1328


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Re: Aluminum vs copper buss bar

Lee Hart
David D. Nelson wrote:
> I'm adding a PakTrakr current sensor to my Gizmo and
> need to use a buss bar. I've made one out of 1/4"
> aluminum but I'm wondering about the issue of
> corrosion and resistence.

I wouldn't use an aluminum in places where it gets wet -- *especially*
not if it gets wet with battery acid! It will corrode at a ferocious rate.

I would use copper for the buss bar. If you have trouble finding a big
enough piece, you can use 2 or 3 layers of thinner copper sheet to get
enough cross section. I would also lead-dip the copper buss bar to
provide corrosion resistance.

--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in    --    Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net

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Re: Aluminum vs copper buss bar

Ryan Stotts
In reply to this post by David D. Nelson
This might be a good source for copper:

http://www.stormcopper.com/

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Re: Aluminum vs copper buss bar

Peter VanDerWal
In reply to this post by Lee Hart
And if you are really desparate for copper bar stock, you can go down to
the local hardware store and pick up a piece of copper tubing.
Smash it flat with a hammer and fold it over as needed to achieve your
desired thickness.
Definitely dip or melt lead over it.

> David D. Nelson wrote:
>> I'm adding a PakTrakr current sensor to my Gizmo and
>> need to use a buss bar. I've made one out of 1/4"
>> aluminum but I'm wondering about the issue of
>> corrosion and resistence.
>
> I wouldn't use an aluminum in places where it gets wet -- *especially*
> not if it gets wet with battery acid! It will corrode at a ferocious rate.
>
> I would use copper for the buss bar. If you have trouble finding a big
> enough piece, you can use 2 or 3 layers of thinner copper sheet to get
> enough cross section. I would also lead-dip the copper buss bar to
> provide corrosion resistance.
>
> --
> Ring the bells that still can ring
> Forget the perfect offering
> There is a crack in everything
> That's how the light gets in    --    Leonard Cohen
> --
> Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>


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Re: Aluminum vs copper buss bar

gowen
  David D. Nelson wrote:
> I'm adding a PakTrakr current sensor to my Gizmo and
> need to use a buss bar. I've made one out of 1/4"
> aluminum but I'm wondering about the issue of
> corrosion and resistence.

Easy enough to find copper bar if you decide to go with it:

http://www.quickshipmetals.com/copper-copper-bar.html

http://www.onlinemetals.com/merchant.cfm?id=253&step=2&top_cat=87

http://store.electrical-insulators-and-copper-ground-bars.com/copper-barstock.htm

http://www.speedymetals.com/c-8009-flat.aspx

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Re: Aluminum vs copper buss bar

Dan Frederiksen-2
In reply to this post by David D. Nelson
no expert but I would be surprised if alu wasn't perfectly fine for it.
it has a bit lower conductivity but that's a matter of making it
slightly bigger
you can do the math on how much large alu has to be to be as good as
copper. both corrode which is why copper is coated too as I understand
it. but I'm guessing even in the worst case scenario the most you will
have to do is scrape the surface when you attach the wires to get good
contact

Dan

David D. Nelson wrote:

>I'm adding a PakTrakr current sensor to my Gizmo and
>need to use a buss bar. I've made one out of 1/4"
>aluminum but I'm wondering about the issue of
>corrosion and resistence. The battery box on a Gizmo
>is not completely protected from moisture. Wind blows
>right over the top of the batteries and in wet weather
>it is common to have a layer of moisture on them.
>Should I go with a copper buss bar instead? If so,
>where can I get some copper bar stock since I can only
>find steel and aluminum?
>
>Thank you,
>
>
>David D. Nelson
>[hidden email]
>
>http://www.austinev.org/evalbum/1328
>
>
>      ____________________________________________________________________________________
>Fussy? Opinionated? Impossible to please? Perfect.  Join Yahoo!'s user panel and lay it on us. http://surveylink.yahoo.com/gmrs/yahoo_panel_invite.asp?a=7 
>
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>  
>

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Re: Aluminum vs copper buss bar

Timothy Balcer
In reply to this post by David D. Nelson
You really don't want to use Aluminium for this as Al is very noble,
so not only will you get oxidation corrosion, you'll get electrolytic
corrosion. Those together in the right conditions could corrode away a
bus bar in a few days. It is one thing to use Aluminum in a sealed
application, but in something exposed like this unless you knew how to
guard the metal against this sort of thing, you might have some
difficulty. Also, FYI, aluminum does not conduct as well as Cu, so
you'll have efficiency losses over Cu since there are so many
connections and bars.

Copper will insulate itself somewhat as it corrodes, and dipped in
lead is a much better alternative to Aluminium. Over the long haul (or
even the short one) using Cu will give you a much, much better service
life and cost you less in the way of replacements due to corrosion,
cracking, and so on.

All of that being said, there are some alloys of Aluminium
(magnesium/silicon type) that can provide excellent service life and
corrosion resistance in this sort of environment, providing better
elasticity and corrosion resistance than even pure Cu, but they would
probably end up costing as much as copper, or more, considering you
need to provide a 50% bigger cross section in order to compensate for
Al conductivity being lower than Cu.

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Re: Aluminum vs copper buss bar

joe-22
In reply to this post by David D. Nelson
Hi. David,

It isn't smart to use an aluminum bus bar, unless it is coated with a
corrosion resistant metal, such as nickel.

Copper is much better, although it still should be coated (electroplated)
with nickel. It is readily available from any electrical shop that replaces
old loadcenters (fuse or circuit breaker boxes) with new ones. Often these
have screw holes already drilled and tapped for small screws. Another source
is scrappies, people who make a few bucks scrapping out metal items. New
ones can be had from Alaska Brass and Copper, or similar outfits, but they
will be relatively costly.

I have quite a collection of used copper buss bars myself, some about 3/16"
thick and over a foot long - if someone needs one like that, e-mail me
off-list at the below address.

Joseph H. Strubhar

Web: www.gremcoinc.com

E-mail: [hidden email]
----- Original Message -----
From: "David D. Nelson" <[hidden email]>
To: <[hidden email]>
Sent: Sunday, September 16, 2007 4:31 PM
Subject: [EVDL] Aluminum vs copper buss bar


> I'm adding a PakTrakr current sensor to my Gizmo and
> need to use a buss bar. I've made one out of 1/4"
> aluminum but I'm wondering about the issue of
> corrosion and resistence. The battery box on a Gizmo
> is not completely protected from moisture. Wind blows
> right over the top of the batteries and in wet weather
> it is common to have a layer of moisture on them.
> Should I go with a copper buss bar instead? If so,
> where can I get some copper bar stock since I can only
> find steel and aluminum?
>
> Thank you,
>
>
> David D. Nelson
> [hidden email]
>
> http://www.austinev.org/evalbum/1328
>
>
>
> ____________________________________________________________________________________
> Fussy? Opinionated? Impossible to please? Perfect.  Join Yahoo!'s user
> panel and lay it on us.
> http://surveylink.yahoo.com/gmrs/yahoo_panel_invite.asp?a=7
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

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Re: Aluminum vs copper buss bar

Lee Hart
In reply to this post by Dan Frederiksen-2
Dan Frederiksen wrote:
> no expert but I would be surprised if alu wasn't perfectly fine for it.
> it has a bit lower conductivity but that's a matter of making it
> slightly bigger
> you can do the math on how much large alu has to be to be as good as
> copper. both corrode which is why copper is coated too as I understand
> it. but I'm guessing even in the worst case scenario the most you will
> have to do is scrape the surface when you attach the wires to get good
> contact.

Aluminum has a number of problems to overcome to make good electrical
connections:

  - It instantly forms an insulating aluminum oxide coating on contact
    with air. Aluminum oxide is an excellent insulator and very hard
    (used as an abrasive).

  - It is very soft, and cold flows under pressure like lead. A
    connection that is tight today will automatically loosen over time.

  - It generates a higher electromotive potential when put against
    most other metals. If it gets wet, this higher voltage leads to
    high corrosion rates (the alumunum usually corrodes away).

  - Aluminum is hard to solder, braze, or weld; making it harder to
    make good connections of these types.

  - Aluminum burns. You don't want combustible materials in electrical
    equipment where loose connections or arcing can easily start a fire.

There are solutions for all these problems, but they involve more cost
and work. And if not done right, you get bad connections.
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in    --    Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net

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Re: Aluminum vs copper buss bar

Dan Frederiksen-2
In reply to this post by joe-22
I see a lot of what I consider to be deeply irrational 'copper is much
better than alu' posts.
the legs of power transisters are made from f'ing aluminium
alu conducts a little poorer by area than copper but make a wire 24%
wider (or 54% greater cross section) and it will conduct just as well

by weight, aluminium is actually a much better conductor than copper

Dan

joe wrote:

>Hi. David,
>
>It isn't smart to use an aluminum bus bar, unless it is coated with a
>corrosion resistant metal, such as nickel.
>
>Copper is much better, although it still should be coated (electroplated)
>with nickel. It is readily available from any electrical shop that replaces
>old loadcenters (fuse or circuit breaker boxes) with new ones. Often these
>have screw holes already drilled and tapped for small screws. Another source
>is scrappies, people who make a few bucks scrapping out metal items. New
>ones can be had from Alaska Brass and Copper, or similar outfits, but they
>will be relatively costly.
>
>I have quite a collection of used copper buss bars myself, some about 3/16"
>thick and over a foot long - if someone needs one like that, e-mail me
>off-list at the below address.
>
>Joseph H. Strubhar
>
>Web: www.gremcoinc.com
>
>E-mail: [hidden email]
>----- Original Message -----
>From: "David D. Nelson" <[hidden email]>
>To: <[hidden email]>
>Sent: Sunday, September 16, 2007 4:31 PM
>Subject: [EVDL] Aluminum vs copper buss bar
>
>
>  
>
>>I'm adding a PakTrakr current sensor to my Gizmo and
>>need to use a buss bar. I've made one out of 1/4"
>>aluminum but I'm wondering about the issue of
>>corrosion and resistence. The battery box on a Gizmo
>>is not completely protected from moisture. Wind blows
>>right over the top of the batteries and in wet weather
>>it is common to have a layer of moisture on them.
>>Should I go with a copper buss bar instead? If so,
>>where can I get some copper bar stock since I can only
>>find steel and aluminum?
>>
>>Thank you,
>>
>>
>>David D. Nelson
>>[hidden email]
>>
>>http://www.austinev.org/evalbum/1328
>>
>>
>>
>>____________________________________________________________________________________
>>Fussy? Opinionated? Impossible to please? Perfect.  Join Yahoo!'s user
>>panel and lay it on us.
>>http://surveylink.yahoo.com/gmrs/yahoo_panel_invite.asp?a=7
>>
>>_______________________________________________
>>For subscription options, see
>>http://lists.sjsu.edu/mailman/listinfo/ev
>>
>>    
>>
>
>_______________________________________________
>For subscription options, see
>http://lists.sjsu.edu/mailman/listinfo/ev
>
>  
>

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Re: Aluminum vs copper buss bar

Roland Wiench
In reply to this post by joe-22
Now that you got your copper bars, it is best to coat them.  About 30 years
ago, we could get lead sticks for vehicle body work, but these sticks are
all lead-free solder.  Not good for using on battery connectors.  What I did
was to pickup up some pure lead battery clamps and use that lead to coat
buss bars.

You can also get pure rolls of lead from a fish and tackle store, which are
use for making weights.

Just melting the lead and trying to coat a buss bar will not work, the lead
will just roll off.  Preheating the bar does not work good either, the lead
looks like a cold solder joint and you can just peal it right off.

What you must do, is to clean a copper bar until it is mirror finish and
quickly apply tinning butter which comes in 1 lb jars from www.eastwood.com.
Use a torch to put on the tinning butter and wipe it smooth with a folded
paper towel while it still molten.  Then preheat it again and start to apply
the lead and wipe again for a smooth surface.

It is best to use the same type of metals at the contact point.  If you are
using a zinc or cadmium plate wire lugs or battery clamps on a lead post,
they may look bright and clean on the non-contact areas, but take one off
after they have been on for a year, and you will see a dark tarnish area
where the two metals made contact which increases the resistance of this
contact.

If the buss bars are contacting other types of metals, than I silver coat
them using a very high content of silver alloy which is use in high
temperature welding, about 1000 F. or more. Not your basic plumbing type
silver solder.  This also takes a special tinning wetting solution.  You can
get this type of product from welding supply companies.

Roland




----- Original Message -----
From: "joe" <[hidden email]>
To: "Electric Vehicle Discussion List" <[hidden email]>
Sent: Monday, September 17, 2007 7:16 AM
Subject: Re: [EVDL] Aluminum vs copper buss bar


> Hi. David,
>
> It isn't smart to use an aluminum bus bar, unless it is coated with a
> corrosion resistant metal, such as nickel.
>
> Copper is much better, although it still should be coated (electroplated)
> with nickel. It is readily available from any electrical shop that
> replaces
> old loadcenters (fuse or circuit breaker boxes) with new ones. Often these
> have screw holes already drilled and tapped for small screws. Another
> source
> is scrappies, people who make a few bucks scrapping out metal items. New
> ones can be had from Alaska Brass and Copper, or similar outfits, but they
> will be relatively costly.
>
> I have quite a collection of used copper buss bars myself, some about
> 3/16"
> thick and over a foot long - if someone needs one like that, e-mail me
> off-list at the below address.
>
> Joseph H. Strubhar
>
> Web: www.gremcoinc.com
>
> E-mail: [hidden email]
> ----- Original Message -----
> From: "David D. Nelson" <[hidden email]>
> To: <[hidden email]>
> Sent: Sunday, September 16, 2007 4:31 PM
> Subject: [EVDL] Aluminum vs copper buss bar
>
>
> > I'm adding a PakTrakr current sensor to my Gizmo and
> > need to use a buss bar. I've made one out of 1/4"
> > aluminum but I'm wondering about the issue of
> > corrosion and resistence. The battery box on a Gizmo
> > is not completely protected from moisture. Wind blows
> > right over the top of the batteries and in wet weather
> > it is common to have a layer of moisture on them.
> > Should I go with a copper buss bar instead? If so,
> > where can I get some copper bar stock since I can only
> > find steel and aluminum?
> >
> > Thank you,
> >
> >
> > David D. Nelson
> > [hidden email]
> >
> > http://www.austinev.org/evalbum/1328
> >
> >
> >
> > ____________________________________________________________________________________
> > Fussy? Opinionated? Impossible to please? Perfect.  Join Yahoo!'s user
> > panel and lay it on us.
> > http://surveylink.yahoo.com/gmrs/yahoo_panel_invite.asp?a=7
> >
> > _______________________________________________
> > For subscription options, see
> > http://lists.sjsu.edu/mailman/listinfo/ev
> >
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
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Re: Aluminum vs copper buss bar

Martin Klingensmith
In reply to this post by Dan Frederiksen-2
Which transistors are you using? All of mine have tin plated copper leads.
--
Martin K

Dan Frederiksen wrote:

> I see a lot of what I consider to be deeply irrational 'copper is much
> better than alu' posts.
> the legs of power transisters are made from f'ing aluminium
> alu conducts a little poorer by area than copper but make a wire 24%
> wider (or 54% greater cross section) and it will conduct just as well
>
> by weight, aluminium is actually a much better conductor than copper
>
> Dan
>
>  

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Re: Aluminum vs copper buss bar

Dewey, Jody R ATC COMNAVAIRLANT, N422G5G
I think he is referring to the ones inside a CPU chip.  They are silicon
with aluminum interconnects.

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On
Behalf Of Martin Klingensmith
Sent: Monday, September 17, 2007 10:59
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Aluminum vs copper buss bar

Which transistors are you using? All of mine have tin plated copper
leads.
--
Martin K

Dan Frederiksen wrote:
> I see a lot of what I consider to be deeply irrational 'copper is much

> better than alu' posts.
> the legs of power transisters are made from f'ing aluminium alu
> conducts a little poorer by area than copper but make a wire 24% wider

> (or 54% greater cross section) and it will conduct just as well
>
> by weight, aluminium is actually a much better conductor than copper
>
> Dan
>
>  

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Re: Aluminum vs copper buss bar

Martin Klingensmith
Those aren't power transistors, and they use copper interconnects now
anyway. Sorry not trying to be a troll.. I'll concede to irrelevance.
--
Martin K

Dewey, Jody R ATC COMNAVAIRLANT, N422G5G wrote:

> I think he is referring to the ones inside a CPU chip.  They are silicon
> with aluminum interconnects.
>
> -----Original Message-----
> From: [hidden email] [mailto:[hidden email]] On
> Behalf Of Martin Klingensmith
> Sent: Monday, September 17, 2007 10:59
> To: Electric Vehicle Discussion List
> Subject: Re: [EVDL] Aluminum vs copper buss bar
>
> Which transistors are you using? All of mine have tin plated copper
> leads.
> --
> Martin K
>
> Dan Frederiksen wrote:
>  
>> I see a lot of what I consider to be deeply irrational 'copper is much
>>    
>
>  
>> better than alu' posts.
>> the legs of power transisters are made from f'ing aluminium alu
>> conducts a little poorer by area than copper but make a wire 24% wider
>>    
>
>  
>> (or 54% greater cross section) and it will conduct just as well
>>
>> by weight, aluminium is actually a much better conductor than copper
>>
>> Dan
>>
>>  
>>    
>
> _______________________________________________
> For subscription options, see
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>  

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Re: Aluminum vs copper buss bar

Dan Frederiksen-2
In reply to this post by Martin Klingensmith
well in all fairness the one I'm considering (TO-247) doesn't say either
way from what I can tell.
http://www.st.com/stonline/products/literature/ds/13241/stgw30nc60vd.pdf
I just once looked for what material the legs were made of in general
(since that seems to matter heatwise) and the one I found was tin plated
alu. obviously some could be copper.
which one is yours?

Dan

Martin Klingensmith wrote:

>Which transistors are you using? All of mine have tin plated copper leads.
>--
>Martin K
>
>Dan Frederiksen wrote:
>  
>
>>I see a lot of what I consider to be deeply irrational 'copper is much
>>better than alu' posts.
>>the legs of power transisters are made from f'ing aluminium
>>alu conducts a little poorer by area than copper but make a wire 24%
>>wider (or 54% greater cross section) and it will conduct just as well
>>
>>by weight, aluminium is actually a much better conductor than copper
>>
>>Dan
>>
>>  
>>    
>>
>
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Re: Aluminum vs copper buss bar

Dan Frederiksen-2
In reply to this post by Martin Klingensmith
this was the spec I found online:
http://www.statschippac.com/NR/rdonlyres/B6B4493B-58E8-4070-8CD4-EC95945AF30A/0/Power.pdf
on the specs on TO-247 on page 2 it says alu wires. maybe that's inside
the chip?
I may have been wrong to suggest the leads are sometimes made of alu but
it seems some part of the circuit is. either way I stand by alu as a
good enough conductor for use as bussbar. maybe it's hard to solder on?
maybe it's hard to nickel plate?

Dan

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Re: Aluminum vs copper buss bar

Martin Klingensmith
In reply to this post by Dan Frederiksen-2
I guess we're both wrong/right!
-
Martin

Dan Frederiksen wrote:

> well in all fairness the one I'm considering (TO-247) doesn't say either
> way from what I can tell.
> http://www.st.com/stonline/products/literature/ds/13241/stgw30nc60vd.pdf
> I just once looked for what material the legs were made of in general
> (since that seems to matter heatwise) and the one I found was tin plated
> alu. obviously some could be copper.
> which one is yours?
>
> Dan
>
>  

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Re: Aluminum vs copper buss bar

ev
In reply to this post by David D. Nelson
>maybe it's hard to solder on?
Yes, it is

>maybe it's hard to nickel plate?
Yes again.

Bill

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Re: Aluminum vs copper buss bar

Dale Ulan
In reply to this post by Dan Frederiksen-2
Metalization on the IC itself is often aluminium, or an alloy of it. Bonding
wires are most commonly aluminium or gold. Gold has historically been used.
Neither metalization nor bonding wires need to be soldered - they are welded
instead. Different alloys need to be layered to make flip-chips (which can
be soldered) - each metal layer offers a specific function as the basic IC
metalization is not suited to soldering. Cr, Cr-Cu, Cu, and Au layers are a
common layer stackup. Al, Ni, Cu is another stackup.

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Re: Aluminum vs copper buss bar

Timothy Balcer
In reply to this post by ev
To add to Lee's post:

YES you could use Aluminium for this application. NO it will not cost
less than copper because of all of the various issues with using
Aluminium in electrical applications, and especially with Aluminium
being combustible (potentially) when in contact with iron oxide.

Essentially, all of the stuff you see using Aluminium is VERY WELL
engineered to take advantage of Aluminium's properties, and to
downplay its problems. In THIS application, to properly compensate so
that you would have aq copper equivalent, you would be spending more
money than on just buying the copper to begin with, and you still may
not have something as good as copper because you might have forgotten
something, or not taken something into account.

First, you would have to use an alloy of aluminium to do this, if you
wanted to deal with the plasticity of the metal causing contacts to
loosen.

Second, you'd have to use 50% more metal by volume.

Third you'd have to plate the aluminium in something that would
prevent the electrolytic corrosion that will happen in the acid
environment you are exposing it to. A serious zinc coating would be
good for a year or so, but thats assuming it never cracks. If it does,
you could lose a busbar in few days.

Fourth you'd have to deal with the Al2O3
(http://en.wikipedia.org/wiki/Aluminium_oxide) problem, in that it is
a decent insulator and could easily cause progressive loss, which
creates heat, which softens the metal , which causes it to shift,
which causes loosening....etc.

....and so on. It's not a simple problem to use Aluminium in
electrical work when it is exposed to weather. It works really well in
boat hulls, for example, but they have HUGE zincs under the water line
to draw away electrolytic corrosion.

This is why I am going to go through  the trouble and expense of
getting nickel plated copper lugs for some BB600s I have. They are so
far superior to SS that it isn't worth the hassle (for me) or the
losses. I know I know.. there are peopole using SS lugs with BB600s..
I just dont want to take that risk. :)

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