Homebrew_PCBs

Dave,
Where have you been? Don't you know that we use copper plated zinc
pennies? And that eating a copper penny is not considered a hazard, but
the zinc coated ones are? I guess the acids in your stomach either
don't dissolve copper, or it requires a lot of copper to be a problem.
Otherwise, lead killed the Roman Empire, but copper will have killed a
_bunch_ of modern countries.
Does anyone know why aluminum is bad for house wiring? (real question,
not a joke) Is it that aluminum has a greater thermal expansion ratio
than copper, and so the connections worked themselves apart?
Thanks
Richard

>But, I'm thinking that here in the US, we use copper pennies and
>copper water pipe so we probalby dump more copper into the waste
>stream than all the pcb houses put togehter.
>
>Dave
>
>

> Does anyone know why aluminum is bad for house wiring? (real question,
> not a joke) Is it that aluminum has a greater thermal expansion ratio
> than copper, and so the connections worked themselves apart?
> Thanks
> Richard

aluminium forms a oxyde layer which is isolating. -> resistance -> heat ->
fire -> no more house...

using aluminium in wiring requires proper techniques when making
connections.
if done right it is ok (e.g. power cables).

However, i know for sure they do not take any care with those aluminium
cables which hook your house to the main power cables...

it is also much more prone to breaking.

ST

If I remember correctly aluminium wire will 'creep' under load so you
lose the contact pressure. This is also a problem with solder so don't
tin your wires if you are using screw terminals or crimps.

Les

Richard Mustakos wrote:

> Dave,
> Where have you been? Don't you know that we use copper plated zinc
> pennies? And that eating a copper penny is not considered a hazard, but
> the zinc coated ones are? I guess the acids in your stomach either
> don't dissolve copper, or it requires a lot of copper to be a problem.
> Otherwise, lead killed the Roman Empire, but copper will have killed a
> _bunch_ of modern countries.
> Does anyone know why aluminum is bad for house wiring? (real question,
> not a joke) Is it that aluminum has a greater thermal expansion ratio
> than copper, and so the connections worked themselves apart?
> Thanks
> Richard
>
>
>>But, I'm thinking that here in the US, we use copper pennies and
>>copper water pipe so we probalby dump more copper into the waste
>>stream than all the pcb houses put togehter.
>>
>>Dave
>>
>>
>
>
>
>
>
> Be sure to visit the group home and check for new Bookmarks and files:
> http://groups.yahoo.com/group/Homebrew_PCBs
> Yahoo! Groups Links
>
>
>
>
>
>

--- In Homebrew_PCBs@yahoogroups.com, Richard Mustakos
<rmustakos@a...> wrote:

> Dave,
> Where have you been? Don't you know that we use copper plated zinc
> pennies?

They are actually steel. Try a magnet on one. 8-)

Leon

In a message dated 5/19/2004 2:53:33 PM Central Standard Time,
les@... writes:
Does anyone know why aluminum is bad for house wiring? (real question, not
a joke) Is it that aluminum has a greater thermal expansion ratio than
copper, and so the connections worked themselves apart?<<
This may CONTRIBUTE to the problem, but the MAIN reason is that aluminum
oxidizes INSTANTLY upon contact with oxygen in the air, and then stops oxidizing
as soon as an invisibly-thin layer of alum.oxide is created (same "chemical" as
saphires or rubies!). Same stuff that is used to make much sandpaper. And
that AlO³ is a "perfect" insulator. So, with that working caused by the
condition in your question, any of that which may have been scraped away and
"contact made" upon initial installation is instantly replaced, as soon as oxygen
touches the bare Al surface, again. This resistance causes heat which FURTHER
exascerbates the problem, and on it goes until the heat so generated becomes
hot enough to melt plastic and start fires. Now, the "heavy stuff" from the
utility may still be aluminum, but that is fastened to the "bus" in the initial
main breaker-panel with specially-treated connectors which (mostly-) impede
this oxide-generation. Thus, $Dollars are saved by using a few short feet of fat
Al wire where copper was used decades ago. It boggles MY tiny mind that the
people who "thought-up the use of Al wire in house-wiring" didn't realize what
they were DOING! The $ speaks loudest, I guess!
Jan Rowland


[Non-text portions of this message have been removed]

Aluminum has more resistance than copper. That's why we use copper.
Copper is a better electric conductor but more expensive. In High voltage
lines the choice is aluminum because is much cheaper than copper. And to
compensate the extra resistance they make the wires thicker. And is still
cheaper than copper. For houses copper is better because it's thinner and
the resistance is minimal.

> > Does anyone know why aluminum is bad for house wiring? (real question,
> > not a joke) Is it that aluminum has a greater thermal expansion ratio
> > than copper, and so the connections worked themselves apart?
> > Thanks
> > Richard

In a message dated 5/19/2004 8:42:21 PM Central Standard Time,
maxq668@... writes:
For houses copper is better because it's thinner and the resistance is
minimal.<<

Max: True copper is better for houses, but NOT for these reasons! Alum.
wire of "equivalent" resistance is only slightly larger in diameter, and, as you
said, STILL lighter in weight. The "size" is too close to be of importance.
The resistance of the "Romex" made with alum. was the same as the copper. The
reason the copper proved the only way to go is that the Alum. FAILS after a
short time after initial installation, as I said in a previous post.


[Non-text portions of this message have been removed]

We're way off topic, but I'll finish this off by explaining the
(mostly) complete reason why the use of aluminum house wiring failed
in the US.

Aluminum has a different (larger) expansion due to temp than copper
does. With the correct fixtures, it is fine and works for a long time.

However, all existing installations and existing wall sockets use
connectors with the alloy's coefficient of expansion matched to
copper. So some people were using cheaper outlets meant for copper
when they replaced or added an outlet in new construction that had all
aluminum wire. This resulted in the cycle of oxidation and heat and
subsequent fire mentioned.

Add to that, you need to size up aluminum wire a bit for the same
current as compared to copper, and people did not understand or didn't
believe it, so that would cause problems.

Aluminum wire is perfectly safe when -all- the fixtures, outlets,
wirenuts, etc. used are made for aluminum wire. Unfortunatly a small
percentage of electricians and a large percentage of homeowners didn't
understand and mixed copper with aluminum, sometimes buying aluminum
wire to replace existing copper without swapping out the outlets and
light fixtures.

The connections made to the aluminum wire where it comes in your house
are made specifically for aluminum wire. The pressure cuts through the
oxide and makes what is called a gas-tight seal, so no further
oxidization occurs and the metals don't experience galvanic corrosion.

There, back to PCBs. ;')

Oh, yeah, current USA "copper" pennies are copper plated zinc.

Steve

Leon,

Not sure where you got this. The last--only--(USA)steel pennies were
made in 1943.

In 1981 they were changed to copper plated Zinc, due to a law which
requires that the inherent metal value cannot exceed the currency
value.

I just checked several, from 1984 to 2004(Denver minted), and none
were attracted by the magnet.

Ballendo



--- In Homebrew_PCBs@yahoogroups.com, "leon_heller"
<leon_heller@h...> wrote:

> --- In Homebrew_PCBs@yahoogroups.com, Richard Mustakos
> <rmustakos@a...> wrote:
> > Dave,
> > Where have you been? Don't you know that we use copper plated

zinc

> > pennies?
>
> They are actually steel. Try a magnet on one. 8-)
>
> Leon

> Now, the "heavy stuff" from the
> utility may still be aluminum, but that is fastened to the "bus" in the
> initial
> main breaker-panel with specially-treated connectors which (mostly-)
> impede
> this oxide-generation.

they use bog-standard screw terminals (big of course).
Not sure what is special about them.
I suspect the cable is no pure aluminum.


I've come across a few farmhouses having alu wiring, must have been done
around wartime, or maybe even before that.

For ligtning conductor alu is standard.
But there small gaps are no problem i guess...

ST

In a message dated 5/20/2004 12:48:12 AM Central Standard Time,
stefan_trethan@... writes:
Not sure what is special about them.<<
The ones I mean have a "grainy" (sand-like) interior with silicone grease all
inside (to keep the Oxygen off the metal, once screwed-TIGHT). Probably the
PRICE is special, too!
I suspect the cable is no pure aluminum<<
It may have trace impurities, but I doubt ANY effort is made to alloy it to
preclude this kind of electrolytic corrosion!

Bet it would be nice if alum. were easily solderable, so PCB's could be made
with it instead of copper!

Does anyone in here doing PCB's at home pretty-much strictly as a hobby do
PTH? Can this be done PRACTICALLY at home? Then, tin-lead resist would be
necessary for trace-etching. How reliably could the conscientious mature
home-tinker do tin-lead plating of a PC-pattern, and be SURE the plating did-good down
in the holes? Jan Rowland


[Non-text portions of this message have been removed]

--- In Homebrew_PCBs@yahoogroups.com, "Steve" <alienrelics@y...>
wrote:

> Oh, yeah, current USA "copper" pennies are copper plated zinc.

And lest anyone think they were pure copper before the 1982 change,
ignoring the 1943 "wartime" steel cent, they were actually bronze
(95%copper, 5% tin and zinc) or brass (95% copper, 5% zinc)
depending on the time period - pure copper is much too soft to use
for coins.

A.J.

--- In Homebrew_PCBs@yahoogroups.com, "ballendo" <ballendo@y...>
wrote:

> Leon,
>
> Not sure where you got this. The last--only--(USA)steel pennies

were

> made in 1943.
>
> In 1981 they were changed to copper plated Zinc, due to a law which
> requires that the inherent metal value cannot exceed the currency
> value.
>
> I just checked several, from 1984 to 2004(Denver minted), and none
> were attracted by the magnet.

I meant UK pennies, the real ones. 8-)

Leon

Jan,

Check out the group links section. Markus Zingg has a VERY nice
setup... (Worth re-creating, IMO) Down side is that he uses Bungard
chemicals, which are not cheap to get started with. But for a
dedicated amateur, the prices weren't TOO bad, IMO. Bungard has a USA
rep in the northwest (chems come from Canada) I made a phone call to
get pricing.

Another member is successfully using the blackhole technique. (I
apologise forgetting his name just now; especially as he was very
helpful in several private emails awhile back. Can't look it up as
I'm not on my "normal" computer!)

Anyways, he uses a combination of thinktink and caswell off-the-shelf
products. He's doing small production, and reports good results.

Hope this helps,

Ballendo

--- In Homebrew_PCBs@yahoogroups.com, JanRwl@A... wrote:
> In a message dated 5/20/2004 12:48:12 AM Central Standard Time,
> stefan_trethan@g... writes:
> Not sure what is special about them.<<
> The ones I mean have a "grainy" (sand-like) interior with silicone
grease all
> inside (to keep the Oxygen off the metal, once screwed-TIGHT).
Probably the
> PRICE is special, too!
> I suspect the cable is no pure aluminum<<
> It may have trace impurities, but I doubt ANY effort is made to
alloy it to
> preclude this kind of electrolytic corrosion!
>
> Bet it would be nice if alum. were easily solderable, so PCB's
could be made
> with it instead of copper!
>
> Does anyone in here doing PCB's at home pretty-much strictly as a
hobby do
> PTH? Can this be done PRACTICALLY at home? Then, tin-lead resist
would be
> necessary for trace-etching. How reliably could the conscientious
mature
> home-tinker do tin-lead plating of a PC-pattern, and be SURE the
plating did-good down
> in the holes? Jan Rowland
>
>
> [Non-text portions of this message have been removed]

That would be me, I was going to do another long winded reply, with a subject change, but instead I hoped the poster would search the archives a-bit.
- also I was going to get you those pics, but got stuck in mad scientist mode, went on vacation, came back and fried my torrodial transformer, and meters, by accidentally letting the + and - clips touch each other ... for an extended period of time. Btw torrodials smell pretty funky as they cook.
I'm working on a new one as we speak, and I'm preparing a showcase website, with pics and stuff of my setup, which I'll toss a link to in the links section.
IF I succeeded at cloning my self... It should be done next week, but if not, next month.

JT
(Jeremy Taylor)

----- Original Message -----
From: ballendo
To: Homebrew_PCBs@yahoogroups.com
Sent: Friday, May 21, 2004 10:21 AM
Subject: [Homebrew_PCBs] Re: Copper Pennies, was First PCB.... neutralizing the HCL


<....>

Another member is successfully using the blackhole technique.





[Non-text portions of this message have been removed]