Electrical Contact Material

[John Fields]

On Sun, 16 Jan 2011 09:51:37 -0500, Jamie
<jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:

John Fields wrote:

On Sat, 15 Jan 2011 18:57:55 -0500, Jamie
jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:


Searcher7 wrote:

On Jan 15, 6:03 pm, John Fields <jfie...@austininstruments.com> wrote:


P.S.: I'll say this. The device I'm designing will incorporate a
wiping motion *between* when the connections are made, so the actual
wiping will not occur between one contact and another, but *before*
they come together, which is why I am looking for a different non-
conductive material for wiping.

Thanks.

Darren Harris
Staten Island, New York.


sacrificial anode ?


---
Since when is a sacrificial anode non-conducting and, why would he
want to fill up the relay with a conductive fluid???

---
JF
The idea was to attract erosion else where.

---
Yes, of course, but how would you go about doing that on relay
contacts using a non-conductive "anode"?
---

Guess you've never seen S-anode contacts.

---
Sure I have.
I used to work at a dry dock in Florida.
---

Similar to wetting.

---
In what way?

---
JF

 

[F. Bertolazzi]

Andrew Gabriel:

Back in the days of punched cards, field service engineers would
often use an (unpunched) card for this purpose. It was just the right
abrasiveness and stiffness for cleaning many things including contact
surfaces and disk head surfaces of that time.

But also to clean the build-up of magnetic material on floppy disc readers'
heads.

Do anybody here use a pencil (or even, for thick oxydations, pen) eraser to
clean contacts?

 

[George Herold]

On Jan 16, 5:14 am, John Fields <jfie...@austininstruments.com> wrote:

On Sat, 15 Jan 2011 16:55:13 -0800 (PST), Searcher7

Search...@mail.con2.com> wrote:
As I mentioned, outside of data lines, voltages will be small(-5V,
+5V, +12V, +24V). And there will be no arcing anyway, because there
will be no current during either make or break. And though not air
tight, this will be an enclosed project. So paper will not do, because
I'm looking for something permanent. A stiff wiping material to put
inside the enclosure.

---
Sounds to me like you're dreaming up a mechanical nightmare, what with
having to put the paper in there, do a little wiping, and then remove
the paper before the contacts close.

Since you're doing dry switching, why not use something hermetically
sealed and totally impervious to dirt and oxidation, like a reed relay
or any of the myriad hermetically sealed miniature relays available?

---
JF

It's not at all clear what the OP is trying to do. Seems like a
little gold flash over his phosphur bronze might get rid of the oxide
issue?

George H.

 

[George Herold]

On Jan 16, 10:31 am, "F. Bertolazzi" <TOGLIe...@MAIUSCOLEtdd.it>
wrote:

Andrew Gabriel:

Back in the days of punched cards, field service engineers would
often use an (unpunched) card for this purpose. It was just the right
abrasiveness and stiffness for cleaning many things including contact
surfaces and disk head surfaces of that time.

But also to clean the build-up of magnetic material on floppy disc readers'
heads.

Do anybody here use a pencil (or even, for thick oxydations, pen) eraser to
clean contacts?

When I was a lad we used erasers to clean the power rails of our slot
car track.

George H.

 

[Baron]

F. Bertolazzi Inscribed thus:

Andrew Gabriel:

Back in the days of punched cards, field service engineers would
often use an (unpunched) card for this purpose. It was just the right
abrasiveness and stiffness for cleaning many things including contact
surfaces and disk head surfaces of that time.

But also to clean the build-up of magnetic material on floppy disc
readers' heads.

Do anybody here use a pencil (or even, for thick oxydations, pen)
eraser to clean contacts?

Yes ! I've used pencil erasers to clean fingering on PCB contacts.

--
Best Regards:
Baron.

 

[Baron]

John Fields Inscribed thus:

On Sat, 15 Jan 2011 16:55:13 -0800 (PST), Searcher7
Searcher7@mail.con2.com> wrote:


As I mentioned, outside of data lines, voltages will be small(-5V,
+5V, +12V, +24V). And there will be no arcing anyway, because there
will be no current during either make or break. And though not air
tight, this will be an enclosed project. So paper will not do, because
I'm looking for something permanent. A stiff wiping material to put
inside the enclosure.

---
Sounds to me like you're dreaming up a mechanical nightmare, what with
having to put the paper in there, do a little wiping, and then remove
the paper before the contacts close.

Since you're doing dry switching, why not use something hermetically
sealed and totally impervious to dirt and oxidation, like a reed relay
or any of the myriad hermetically sealed miniature relays available?


---
JF

Certain types of gaming machines use a stack of rotating disks of SRBP
material, similar construction to a HDD platter stack, with phosphor
bronze contact strips and sterling silver studs to determine payout
values. The contact strips when not in contact with the studs are in
continuous contact with the SRBP disk. Surprisingly over a long period
of time grooves are formed in the SRBP disk surface. Since there is
240v 50Hz present on the contact studs, debris from the continual
friction can cause arcing and breakdown of the SRBP material. The
point being is that these things run reliably for years without
maintenance.

--
Best Regards:
Baron.

 

[Andrew Gabriel]

In article <pdh8fexn64bv$.1dpebl8fwzum0.dlg@40tude.net>,
"F. Bertolazzi" <TOGLIeset@MAIUSCOLEtdd.it> writes:

Andrew Gabriel:

Back in the days of punched cards, field service engineers would
often use an (unpunched) card for this purpose. It was just the right
abrasiveness and stiffness for cleaning many things including contact
surfaces and disk head surfaces of that time.

But also to clean the build-up of magnetic material on floppy disc readers'
heads.

Do anybody here use a pencil (or even, for thick oxydations, pen) eraser to
clean contacts?

Our field service staff had a sort of glass fiber propelling pencil
for that. It was like a very thick propelling pencil, but instead of
pencil lead, it had a dense mass of fine glass fibers, which wore
down over time.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

 

[John Fields]

On Sun, 16 Jan 2011 08:41:08 +0000 (UTC), andrew@cucumber.demon.co.uk
(Andrew Gabriel) wrote:

In article <ac4758d0-9d9c-4585-b9b7-e62bf97606af@k25g2000vbl.googlegroups.com>,
Nunya <jack_shephard@cox.net> writes:
The PROPER method to clean an electrical contact (pair) *that is
meant to be serviceable*, is by a process known as "burnishing".
The tool is a flat strip of thin metal with a face surface texture of
about 3600 grit. Short of having such an easily obtainable tool,
the best and second and ONLY other proper method is the "paper"
suggestion, but I would choose something a little stiffer than paper
towel, also exhibiting far less fiber.

Back in the days of punched cards, field service engineers would
often use an (unpunched) card for this purpose. It was just the right
abrasiveness and stiffness for cleaning many things including contact
surfaces and disk head surfaces of that time. Cards were cleaned of
loose dust during manufacture to prevent dust shedding into card
punches and readers. They were also made of paper which doesn't
soften if it gets wet, so you could if necessary use water or a
solvent on them too, whilst still staying abrasive and without going
soggy (although they were mostly used dry).

Paper tape had the same properties, but was thinner, and finer level
of abrasiveness.

---
Unfortunately, most, if not all, (as I recall) paper tape was oiled in
order to increase the life of the punches, so wasn't really a good
contact-cleaning medium in the long run.

---
JF

 

[John Fields]

On Sun, 16 Jan 2011 08:21:22 -0800 (PST), George Herold
<gherold@teachspin.com> wrote:

On Jan 16, 5:14 am, John Fields <jfie...@austininstruments.com> wrote:
On Sat, 15 Jan 2011 16:55:13 -0800 (PST), Searcher7

Search...@mail.con2.com> wrote:
As I mentioned, outside of data lines, voltages will be small(-5V,
+5V, +12V, +24V). And there will be no arcing anyway, because there
will be no current during either make or break. And though not air
tight, this will be an enclosed project. So paper will not do, because
I'm looking for something permanent. A stiff wiping material to put
inside the enclosure.

---
Sounds to me like you're dreaming up a mechanical nightmare, what with
having to put the paper in there, do a little wiping, and then remove
the paper before the contacts close.

Since you're doing dry switching, why not use something hermetically
sealed and totally impervious to dirt and oxidation, like a reed relay
or any of the myriad hermetically sealed miniature relays available?

---
JF

It's not at all clear what the OP is trying to do. Seems like a
little gold flash over his phosphur bronze might get rid of the oxide
issue?

George H.

---
Maybe, maybe not.

If there's a wear issue, then the gold flash will just be wasted but
who knows?

The OP seems to be operating under "Loose Lips Sink Ships" so we may
never know what we helped him get to market.

---
JF

 

[The Ghost In The Machine]

On Jan 16, 2:04 pm, and...@cucumber.demon.co.uk (Andrew Gabriel)
wrote:

In article <pdh8fexn64bv$.1dpebl8fwzum0....@40tude.net>,
        "F. Bertolazzi" <TOGLIe...@MAIUSCOLEtdd.it> writes:

Andrew Gabriel:

Back in the days of punched cards, field service engineers would
often use an (unpunched) card for this purpose. It was just the right
abrasiveness and stiffness for cleaning many things including contact
surfaces and disk head surfaces of that time.

But also to clean the build-up of magnetic material on floppy disc readers'
heads.

Do anybody here use a pencil (or even, for thick oxydations, pen) eraser to
clean contacts?

Our field service staff had a sort of glass fiber propelling pencil
for that. It was like a very thick propelling pencil, but instead of
pencil lead, it had a dense mass of fine glass fibers, which wore
down over time.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
I DONT KNOW, GLASS FIBER MAY SCRATCH A SOFT METALIC SURFACE.

RUBBER ON MAGNETIC HEADS IS GOOD BUT YOUD HAVE TO PPLISH THE SURFAC
AGAIN..
FOR THE OP's PROBLEM A GOOD QUALITY SPRAY ELECTRONIC CLEANER WITH THE
CIRCUIT DE-ENERGIZED AND MILD AIR BLASTS AFTER A GOOD THOROUGH FLUSH
WILL SUFFICE.

YOU CAN DO MAGIC...YOU CAN DO ANYTHING THAT YOU DESIRE.

PATECUM

 

[Searcher7]

On Jan 16, 11:21 am, George Herold <gher...@teachspin.com> wrote:

On Jan 16, 5:14 am, John Fields <jfie...@austininstruments.com> wrote:



On Sat, 15 Jan 2011 16:55:13 -0800 (PST), Searcher7

Search...@mail.con2.com> wrote:
As I mentioned, outside of data lines, voltages will be small(-5V,
+5V, +12V, +24V). And there will be no arcing anyway, because there
will be no current during either make or break. And though not air
tight, this will be an enclosed project. So paper will not do, because
I'm looking for something permanent. A stiff wiping material to put
inside the enclosure.

---
Sounds to me like you're dreaming up a mechanical nightmare, what with
having to put the paper in there, do a little wiping, and then remove
the paper before the contacts close.

Since you're doing dry switching, why not use something hermetically
sealed and totally impervious to dirt and oxidation, like a reed relay
or any of the myriad hermetically sealed miniature relays available?

---
JF

It's not at all clear what the OP is trying to do.  Seems like a
little gold flash over his phosphur bronze might get rid of the oxide
issue?

George H.

Even with gold there is still the issue of having to clean the
contacts.

P.S.: I don't know if anyone else has this issue, but Google Groups
will not let me post in another thread here that I started called.
Making cables". I've attempting to post a response for the last three
days. Has anyone else had a problem like this?

Thanks.

Darren Harris
Staten Island, New York.

 

[John Fields]

On Sun, 16 Jan 2011 16:31:42 +0100, "F. Bertolazzi"
<TOGLIeset@MAIUSCOLEtdd.it> wrote:

Andrew Gabriel:

Back in the days of punched cards, field service engineers would
often use an (unpunched) card for this purpose. It was just the right
abrasiveness and stiffness for cleaning many things including contact
surfaces and disk head surfaces of that time.

But also to clean the build-up of magnetic material on floppy disc readers'
heads.

Do anybody here use a pencil (or even, for thick oxydations, pen) eraser to
clean contacts?

---
Real life horror story:

Once upon a time, in a previous life, I used to design oceanographic
instruments and farmed out the interface between a submersible Sound
velocity/Temperature/Depth (STD) probe and the surface data
acquisition system.

When we got the interface back it worked perfectly, and we took it to
Japan and installed it on the ship doing the STD profiling of the Sea
of Japan.

At first, everything was ducky, but then we started getting anomalous
readings that made no sense.

Long story short, the PCB contact fingers were tin-lead, the backplane
receptacles were gold, and the sea air did a number on the PCB
contacts.

Solution, until the emergency ordered goldfingered PCB's arrived?

Unplug all of the interface's PCBs, rub down their contacts with an
eraser, plug them back in, and start a run.

---
JF

 

[John Fields]

On Sun, 16 Jan 2011 15:32:41 -0800 (PST), Searcher7
<Searcher7@mail.con2.com> wrote:

On Jan 16, 11:21 am, George Herold <gher...@teachspin.com> wrote:
On Jan 16, 5:14 am, John Fields <jfie...@austininstruments.com> wrote:



On Sat, 15 Jan 2011 16:55:13 -0800 (PST), Searcher7

Search...@mail.con2.com> wrote:
As I mentioned, outside of data lines, voltages will be small(-5V,
+5V, +12V, +24V). And there will be no arcing anyway, because there
will be no current during either make or break. And though not air
tight, this will be an enclosed project. So paper will not do, because
I'm looking for something permanent. A stiff wiping material to put
inside the enclosure.

---
Sounds to me like you're dreaming up a mechanical nightmare, what with
having to put the paper in there, do a little wiping, and then remove
the paper before the contacts close.

Since you're doing dry switching, why not use something hermetically
sealed and totally impervious to dirt and oxidation, like a reed relay
or any of the myriad hermetically sealed miniature relays available?

---
JF

It's not at all clear what the OP is trying to do.  Seems like a
little gold flash over his phosphur bronze might get rid of the oxide
issue?

George H.

Even with gold there is still the issue of having to clean the
contacts.

P.S.: I don't know if anyone else has this issue, but Google Groups
will not let me post in another thread here that I started called.
Making cables". I've attempting to post a response for the last three
days. Has anyone else had a problem like this?

Thanks.

Darren Harris
Staten Island, New York.

---
Google groups, as far as USENET is concerned, is nothing more than a
web based SPAM outlet looking for revenue, and bites.

If you're really interested in verbal freedom and want to say what you
want to say without your network provider getting on your case, then
blow off google groups and get yourself a real USENET provider.

---
JF

 

[Rich Grise]

F. Bertolazzi wrote:

Andrew Gabriel:

Back in the days of punched cards, field service engineers would
often use an (unpunched) card for this purpose. It was just the right
abrasiveness and stiffness for cleaning many things including contact
surfaces and disk head surfaces of that time.

But also to clean the build-up of magnetic material on floppy disc
readers' heads.

Do anybody here use a pencil (or even, for thick oxydations, pen) eraser
to clean contacts?

When I was an amusement machine repairmen, the company issued a thing that
the boss called a "fiberglass eraser" for cleaning edge connector contacts.

It was just a bundle of stiff glass fibers in a plastic tube with a screw
to extend the bundle of fibers as they wore down, and it worked a treat!

It didn't leave any rubber residue like a pencil eraser might have.

Cheers!
Rich

 

[Rich Grise]

John Fields wrote:

On Sun, 16 Jan 2011 08:21:22 -0800 (PST), George Herold
On Jan 16, 5:14 am, John Fields <jfie...@austininstruments.com> wrote:
On Sat, 15 Jan 2011 16:55:13 -0800 (PST), Searcher7

As I mentioned, outside of data lines, voltages will be small(-5V,
+5V, +12V, +24V). And there will be no arcing anyway, because there
will be no current during either make or break. And though not air
tight, this will be an enclosed project. So paper will not do, because
I'm looking for something permanent. A stiff wiping material to put
inside the enclosure.

Sounds to me like you're dreaming up a mechanical nightmare, what with
having to put the paper in there, do a little wiping, and then remove
the paper before the contacts close.

Since you're doing dry switching, why not use something hermetically
sealed and totally impervious to dirt and oxidation, like a reed relay
or any of the myriad hermetically sealed miniature relays available?

It's not at all clear what the OP is trying to do. Seems like a
little gold flash over his phosphur bronze might get rid of the oxide
issue?

Maybe, maybe not.

If there's a wear issue, then the gold flash will just be wasted but
who knows?

The OP seems to be operating under "Loose Lips Sink Ships" so we may
never know what we helped him get to market.

To me, it sounds like a homework problem; I invented some contacts once;
actually, I rescued them from a retired relay and just changed the
mechanical configuration; this guy sounds like he's trying to reinvent the
whole concept of relay contacts, or either he's a troll, twitting us all.

Isn't it frustrating when someone comes in and asks a question, and answer
after answer, he says, "No, that's not it..."

After about three of those kind of responses, I just put them on my "ignore"
list. Sometimes I say, "Well, what the hell _do_ you want to hear?"

Cheers!
Rich

 

[Rich Grise]

Searcher7 wrote:

Even with gold there is still the issue of having to clean the
contacts.

WHAT THE FUCK ARE YOU TRYING TO ACCOMPLISH? People have been doing

this stuff for decades! What's impelling you to reject every reasonable
answer you've gotten? Are you on a secret mission from an alien planet
or what?

Or are you just another damned troll?

Thanks,
Rich

 

[Searcher7]

On Jan 16, 10:27 pm, Rich Grise <ri...@example.net.invalid> wrote:

Searcher7 wrote:

Even with gold there is still the issue of having to clean the
contacts.

WHAT THE FUCK ARE YOU TRYING TO ACCOMPLISH? People have been doing
this stuff for decades! What's impelling you to reject every reasonable
answer you've gotten? Are you on a secret mission from an alien planet
or what?

Or are you just another damned troll?

Thanks,
Rich

Someone piss in your Corn Flakes?

I've said enough. And no. No one has answered my question. Why is it a
crime for me to look for a permanent non-conductive solid wiping
material to be used in an enclosure for Phosphor-Bronze contacts?

This thread should have ended way back when I said that I'll just have
to experiment to find such a material myself. (In fact, I may just be
forced to just design to use Phosphor-Bronze itself as the wiping
material, even though it is conductive).

There is no need for you to respond further.

Darren Harris
Staten Island, New York.

 

[John G]

Searcher7 formulated the question :

On Jan 16, 10:27 pm, Rich Grise <ri...@example.net.invalid> wrote:
Searcher7 wrote:

Even with gold there is still the issue of having to clean the
contacts.

WHAT THE FUCK ARE YOU TRYING TO ACCOMPLISH? People have been doing
this stuff for decades! What's impelling you to reject every reasonable
answer you've gotten? Are you on a secret mission from an alien planet
or what?

Or are you just another damned troll?

Thanks,
Rich

Someone piss in your Corn Flakes?

I've said enough. And no. No one has answered my question. Why is it a
crime for me to look for a permanent non-conductive solid wiping
material to be used in an enclosure for Phosphor-Bronze contacts?

This thread should have ended way back when I said that I'll just have
to experiment to find such a material myself. (In fact, I may just be
forced to just design to use Phosphor-Bronze itself as the wiping
material, even though it is conductive).

There is no need for you to respond further.

Darren Harris
Staten Island, New York.

Darren
It's your cornflakes that are contaminated.

Just why do you need this magic wiping contact?

There are millions, even billions, of contacts to pcbs etc, some of
which have been in service for 40 years and are still working.

As I have asked many times of people with "Problems"
Wots your REAL problem?

If you cannot adequately describe your problem then nobody can help
you.

--
John G

 

[Jasen Betts]

On 2011-01-17, Searcher7 <Searcher7@mail.con2.com> wrote:

I've said enough. And no. No one has answered my question. Why is it a
crime for me to look for a permanent non-conductive solid wiping
material to be used in an enclosure for Phosphor-Bronze contacts?

It's not a crime to be (or act) crazy.

I've seen tamper switches which use part of the nylon plunger to separate
and wipe the contacts, I suspect these switches are not designed for a high
number of operations before failure

This thread should have ended way back when I said that I'll just have
to experiment to find such a material myself.

Who died and made you king?

(In fact, I may just be
forced to just design to use Phosphor-Bronze itself as the wiping
material, even though it is conductive).

It'll exactly match the hardness of the contacts which may be an
advantage.

There is no need for you to respond further.

like that will stop anyone?

 

[Baron]

Rich Grise Inscribed thus:

F. Bertolazzi wrote:
Andrew Gabriel:

Back in the days of punched cards, field service engineers would
often use an (unpunched) card for this purpose. It was just the
right abrasiveness and stiffness for cleaning many things including
contact surfaces and disk head surfaces of that time.

But also to clean the build-up of magnetic material on floppy disc
readers' heads.

Do anybody here use a pencil (or even, for thick oxydations, pen)
eraser to clean contacts?

When I was an amusement machine repairmen, the company issued a thing
that the boss called a "fiberglass eraser" for cleaning edge connector
contacts.

It was just a bundle of stiff glass fibers in a plastic tube with a
screw to extend the bundle of fibers as they wore down, and it worked
a treat!

It didn't leave any rubber residue like a pencil eraser might have.

Cheers!
Rich

Its very much "Horses for Courses" ! The Glass brush that you refer to
are available right up to 2" diameter, and are very abrasive.

--
Best Regards:
Baron.