the REAL problem with my Dustbuster...

[William Sommerwerck]

But there's a spring applying pressure.

Bend the flat wire over a few times and you'll get
some spring pressure.

It's too short. And I want a "permanet" fix.

 

[William Sommerwerck]

You're an idiot to suggest epoxy. The contacts will oxidize and then
there will be no connection, might take a couple of months before
this happens, but it will happen.

Ok, I'll bite. Stainless or nickel oxidize? What electrolyte is in
epoxy that will attack stainless steel or nickel? Meanwhile, I can
buy epoxy paint, epoxy coated rebar, conductive (aluminum doped)
epoxy, epoxy covering junction coating for cheap PCB packaging, etc.
I can also buy quite a few fiberglass marine hulls and decks, which are
held together by epoxy and have stainless deck fittings. No corrosion
warnings on any of the epoxy cans, bottles, and tubes that I can find.
It's certainly not hydroscopic so there's no electrolytic action. The
stainless and nickel are fairly close on the galvanic series:
http://www.corrosionist.com/galvanic_corrosion_chart.htm

Sigh. Where is Dr. Barry L. Ornitz when we need him?

Is this your reference? I'm not sure I see the connection (other than the
general one of chemical reactions between dissimilar substances).

http://www.natscience.com/Uwe/Forum.aspx/chem/9657/Plasticizer-problem

Basic rule -- all discussions eventually get out of hand.

Another rule... If simply pressing two surfaces together made for a good
electrical connection, we'd need much less solder.

You've no doubt read stories about how unsoldered connections lasted a week,
a month, a year -- but eventually failed. Solder creates an alloy bond that
doesn't slowly deteriorate from exposure to oxygen and contaminants.

Before someone mentions wire wrap... In wire wrapping, the wire actually
cuts into the post, forming a gas-tight connection.

 

[Jeff Liebermann]

On Thu, 10 Mar 2011 04:35:00 -0800, "William Sommerwerck"
<grizzledgeezer@comcast.net> wrote:

You're an idiot to suggest epoxy. The contacts will oxidize and then
there will be no connection, might take a couple of months before
this happens, but it will happen.

Ok, I'll bite. Stainless or nickel oxidize? What electrolyte is in
epoxy that will attack stainless steel or nickel? Meanwhile, I can
buy epoxy paint, epoxy coated rebar, conductive (aluminum doped)
epoxy, epoxy covering junction coating for cheap PCB packaging, etc.
I can also buy quite a few fiberglass marine hulls and decks, which are
held together by epoxy and have stainless deck fittings. No corrosion
warnings on any of the epoxy cans, bottles, and tubes that I can find.
It's certainly not hydroscopic so there's no electrolytic action. The
stainless and nickel are fairly close on the galvanic series:
http://www.corrosionist.com/galvanic_corrosion_chart.htm

Sigh. Where is Dr. Barry L. Ornitz when we need him?

Is this your reference? I'm not sure I see the connection (other than the
general one of chemical reactions between dissimilar substances).

http://www.natscience.com/Uwe/Forum.aspx/chem/9657/Plasticizer-problem

No. That's for soft rubber. Plasticizer is what softens plastics.
Quite the opposite in epoxies.

However, after doing my homework AFTER posting the above, I recalled
that stainless will self corrode:
<http://yarchive.net/electr/galvanic_corrosion.html>
"In an earlier post, I mentioned that the stainless alloys can
galvanically corrode by themselves without the presence of a
dissimilar metal. This characteristic is a property of almost
all nickel alloys not just the 18-8 (400 series) and 18-8-3
(300 series) of stainless alloys. It is indeed unfortunate
that these alloys were given the name "stainless" since they
can often corrode under relatively mild conditions."
However, that takes years, not months as the OP alleges.

Basic rule -- all discussions eventually get out of hand.

Yep. I consider myself part of the problem, not the solution. I also
don't like being called an idiot by someone that doesn't bother to
substantiate their allegations. If this discussion had remained on
the original topic (Dustbuster), I would have been terminally bored
and not bothered reading further. Sometimes the topic drift is more
interesting than the original topic. I'm far more interested in
building capacitive discharge spot welders than fixing dust busters.

Another rule... If simply pressing two surfaces together made for a good
electrical connection, we'd need much less solder.

I guess we need to throw out all the flashlight battery designs and
similar battery holders. I could probably get an adequate connection
by simply pressing the flat wire to the battery terminal, and jamming
it in place with an added spring, rubber block, or wad of something
compressible. However, if the current drain really is 3A, not the 1A
I was guessing, it probably won't last.

You've no doubt read stories about how unsoldered connections lasted a week,
a month, a year -- but eventually failed.

Sure. Most of those failures are from corrosion. If you
environmentally isolate the junction, such as burying it under a blob
of epoxy (or other glue), it's unlikely to corrode. The rest are from
arcing, which can be reduced by avoiding pointy contacts.

Solder creates an alloy bond that
doesn't slowly deteriorate from exposure to oxygen and contaminants.

Yep. (Reminder: I used to design marine radios.)

Before someone mentions wire wrap... In wire wrapping, the wire actually
cuts into the post, forming a gas-tight connection.

Yep.


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[William Sommerwerck]

Another rule... If simply pressing two surfaces together made
for a good electrical connection, we'd need much less solder.

I guess we need to throw out all the flashlight battery designs
and similar battery holders.

I earlier made a remark about springs -- which flashlights and battery
holders have in abundance. Sometimes the battery holder /is/ the spring.

I just got back from Batteries Plus. The guy was courteous, and I bought
some 9V batteries I needed. I reinstalled the battery, and everything is now
hunky-dorey. Knowing my luck, the battery will fail tomorrow (though I doubt
it).

 

[Jeff Liebermann]

On Thu, 10 Mar 2011 09:58:09 -0800, "William Sommerwerck"
<grizzledgeezer@comcast.net> wrote:

Another rule... If simply pressing two surfaces together made
for a good electrical connection, we'd need much less solder.

I guess we need to throw out all the flashlight battery designs
and similar battery holders.

I earlier made a remark about springs -- which flashlights and battery
holders have in abundance. Sometimes the battery holder /is/ the spring.

Yep. I have a few of those that use "flexible" plastic to provide the
spring tension. They last about 5-10 years, until the plasticizer
dries out. Then, they remain permantently deformed, or cold flow into
a useless shape. I hit them with a hot air gun, and try to melt the
plastic back in shape. Sometimes it works, but usually, all the
tension is gone.

I just got back from Batteries Plus. The guy was courteous, and I bought
some 9V batteries I needed. I reinstalled the battery, and everything is now
hunky-dorey. Knowing my luck, the battery will fail tomorrow (though I doubt
it).

Nice. Is it too late to have you measure the operating current of the
Dustbuster to satisify my curiosity?


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[William Sommerwerck]

I just got back from Batteries Plus. The guy was courteous,
and I bought some 9V batteries I needed. I reinstalled the
battery, and everything is now hunky-dorey. Knowing my luck,
the battery will fail tomorrow (though I doubt it).

Nice. Is it too late to have you measure the operating current
of the Dustbuster to satisify my curiosity?

It is. I've unbuttoned and rebuttoned it so many times I don't feel like
doing it again. But I suspect your 3A estimate is good. The unit uses sub-C
cells, and runs less than 20 minutes on high -- probably closer to 10.

 

[Wild_Bill]

There is no cutting action in the wirewrap process.. and the post/terminal
isn't typically deformed, the wire is.

The round wire surface is displaced by the corners of the post (conforms to
the corners), breaking thru any surface oxidation of the surfaces, and
creating the gas-tight, electrically secure mechanical connection after
several/6 wraps are completed.

--
Cheers,
WB
..............


"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
news:ilagj4$8v9$1@news.eternal-september.org...

Before someone mentions wire wrap... In wire wrapping, the wire actually
cuts into the post, forming a gas-tight connection.