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Cold soldering with batteries?!?

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July 12, 2005 11:08:13 AM

Archived from groups: rec.audio.pro (More info?)

I was at Home Depot a few weeks ago and in one of the displays toward
the front of the store there was a "soldering iron" that ran on AA's
(if I remember correctly - batteries anyhow). I was in a hurry so I
didn't take a real close look, but the front of the package seemed to
claim that it didn't even heat up (you couldn't burn yourself with the
tip). Can it boil water at room temp too? Has anyone seen one of
these? What gives?
Anonymous
July 12, 2005 11:46:20 AM

Archived from groups: rec.audio.pro (More info?)

apa wrote:
> I was at Home Depot a few weeks ago and in one of the displays toward
> the front of the store there was a "soldering iron" that ran on AA's
> (if I remember correctly - batteries anyhow). I was in a hurry so I
> didn't take a real close look, but the front of the package seemed to
> claim that it didn't even heat up (you couldn't burn yourself with the
> tip). Can it boil water at room temp too? Has anyone seen one of
> these? What gives?

It does heat up, but very very quickly and only when the tip
contacts conductive material (solder *or* the wires to be joined for
example, and it cools down very fast as well. Here's part of the "As
seen on TV" blurb...

"The patented Split-Tip™ combines unique material properties into two
electrically insulated electrodes that form part of an internal
electrical circuit. When the tip's two electrodes make simultaneous
contact with an electrically conductive material such as the work piece
(wire lead, terminal, solder, PCB pad, or other material), this circuit
is completed and the high-resistance electrodes generate instantaneous
heat at the tip. The heat is then rapidly transmitted to the work piece
to complete the quickest soldering joint possible."

http://www.drugstore.com/products/prod.asp?pid=95439&ca...

Will Miho
NY Music and TV Audio Guy
Staff Audio/Fox News/M-AES
"The large print giveth and the small print taketh away..." Tom Waits
Anonymous
July 12, 2005 2:17:19 PM

Archived from groups: rec.audio.pro (More info?)

"apa" <tacoma57@hotmail.com> wrote in message
news:1121177292.917101.180560@g47g2000cwa.googlegroups.com
> I was at Home Depot a few weeks ago and in one of the
displays
> toward the front of the store there was a "soldering iron"
> that ran on AA's (if I remember correctly - batteries
anyhow).
> I was in a hurry so I didn't take a real close look, but
the
> front of the package seemed to claim that it didn't even
heat
> up (you couldn't burn yourself with the tip). Can it boil
> water at room temp too? Has anyone seen one of these?
What
> gives?

Based on what I've seen, this product melts the solder
directly by passing a current through it. So, the solder
gets hot but the contacts cool off rapidly.

Not the best way to solder, IME.
Related resources
Anonymous
July 12, 2005 3:18:27 PM

Archived from groups: rec.audio.pro (More info?)

Arny Krueger <arnyk@hotpop.com> wrote:
>"apa" <tacoma57@hotmail.com> wrote in message
>> I was at Home Depot a few weeks ago and in one of the
>displays
>> toward the front of the store there was a "soldering iron"
>> that ran on AA's (if I remember correctly - batteries
>anyhow).
>> I was in a hurry so I didn't take a real close look, but
>the
>> front of the package seemed to claim that it didn't even
>heat
>> up (you couldn't burn yourself with the tip). Can it boil
>> water at room temp too? Has anyone seen one of these?
>What
>> gives?
>
>Based on what I've seen, this product melts the solder
>directly by passing a current through it. So, the solder
>gets hot but the contacts cool off rapidly.
>
>Not the best way to solder, IME.

This was a bad idea when Sears tried it in the 1960s. It is still
a bad idea today.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
July 12, 2005 3:18:28 PM

Archived from groups: rec.audio.pro (More info?)

"Scott Dorsey" wrote ...
> This was a bad idea when Sears tried it in the 1960s.
> It is still a bad idea today.

The statute of limitations has expired.
Old, bad ideas from previous decades are resuscitated
on TV with disgusting regularity.

Some people have made a career of it (Ron Popiel, et.al.)
Anyone want to take a wager on when the Popiel Pocket
Fisherman will re-appear in a 30-minute infomercial? :-)
http://www.ronco.com/history_of_ronco.di4
Anonymous
July 12, 2005 8:07:35 PM

Archived from groups: rec.audio.pro (More info?)

Actually, this type of soldering has been used industrially for decades.

The problem with the Cold Heat soldering iron is that it's suitable only for
small connections. You're not going to melt the solder in the center
conductor on an RG-59U connector.
Anonymous
July 12, 2005 9:54:26 PM

Archived from groups: rec.audio.pro (More info?)

Why would anyone want to purposely make a "cold solder" joint ?

rd
Anonymous
July 12, 2005 10:25:28 PM

Archived from groups: rec.audio.pro (More info?)

> Why would anyone want to purposely make a "cold solder" joint?

My favorite part of the commercial is when the guy finishes the joint, then
drops the iron into his pocket -- and we're told its temperature quickly
drops from 800 to 0 degrees!

In case you're not up on thermodynamics, that's impossible. Would that it
were...
Anonymous
July 13, 2005 12:16:20 AM

Archived from groups: rec.audio.pro (More info?)

On 12 Jul 2005 07:08:13 -0700, "apa" <tacoma57@hotmail.com> wrote:

>I was at Home Depot a few weeks ago and in one of the displays toward
>the front of the store there was a "soldering iron" that ran on AA's
>(if I remember correctly - batteries anyhow). I was in a hurry so I
>didn't take a real close look, but the front of the package seemed to
>claim that it didn't even heat up (you couldn't burn yourself with the
>tip). Can it boil water at room temp too? Has anyone seen one of
>these? What gives?

Others have described it I recall seeing TV ads a year ago and
there being a thread on it on (IIRC) sci.electronics.design. I heard
it described decades ago as "resistance soldering" (resistance of the
wires or traces being soldered, not of the heating element in the
iron). Among the other listed concerns, I'd worry about it putting an
inappropriate voltage (1.5 to 3 volts?) with high available current
across a sensitive component (forward bias of a signal diode or E-B
junction of a signal BJT).


-----
http://www.mindspring.com/~benbradley
Anonymous
July 13, 2005 12:36:44 AM

Archived from groups: rec.audio.pro (More info?)

Well... I had to try it myself a while back. The tip is split, and
current flows when both sides are in contact, as already noted. Also,
the tips are some kind of conductive composite, not copper or nickel or
iron.

It takes ridiculously perfect alignment to keep the two split tips in
contact; the current is constantly fluctuating on and off, very
difficult to maintain any heat. It won't work right if you press too
hard. It's more like arc welding than soldering. And the tips start
to degrade and crumble very quickly.

Anyway, I tried several times to solder an XLR connector, and some
other small parts... finally gave up, put it all back in the box and
returned for the "money back guarantee", which I got.

It _does_ actually cool off pretty quickly, probably because it's not
metal. But also because it's a PITA to _get_ any heat in it. They're
everywhere now... saw one at Radio Shack the other night, the salesman
"loved his".

Steve
Anonymous
July 13, 2005 1:39:55 AM

Archived from groups: rec.audio.pro (More info?)

"apa" <tacoma57@hotmail.com> wrote in message
news:1121177292.917101.180560@g47g2000cwa.googlegroups.com...
>I was at Home Depot a few weeks ago and in one of the displays toward
> the front of the store there was a "soldering iron" that ran on AA's
> (if I remember correctly - batteries anyhow). I was in a hurry so I
> didn't take a real close look, but the front of the package seemed to
> claim that it didn't even heat up (you couldn't burn yourself with the
> tip). Can it boil water at room temp too? Has anyone seen one of
> these? What gives?


My daughter bought me one last year for Father's Day. These things are
marginal for building cables and disasterous for replacing components.

CA
Anonymous
July 13, 2005 4:20:05 AM

Archived from groups: rec.audio.pro (More info?)

"apa"
>
>I was at Home Depot a few weeks ago and in one of the displays toward
> the front of the store there was a "soldering iron" that ran on AA's
> (if I remember correctly - batteries anyhow). I was in a hurry so I
> didn't take a real close look, but the front of the package seemed to
> claim that it didn't even heat up (you couldn't burn yourself with the
> tip). Can it boil water at room temp too? Has anyone seen one of
> these? What gives?
>


** Sounds like the same POS advertised on a shonky web site.

Apparently relies on " I squared R " heating of solder in the local
rea - rather than conduction of thermal energy.

Dangerous, dodgy and stupid - to say the least.

The AA cells may easily explode due to overheating if shorted - something
all makers warn against.




.......... Phil
Anonymous
July 13, 2005 4:20:06 AM

Archived from groups: rec.audio.pro (More info?)

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:3ji1sgFq59uoU1@individual.net...
>
> "apa"
> >
> >I was at Home Depot a few weeks ago and in one of the displays toward
> > the front of the store there was a "soldering iron" that ran on AA's
> > (if I remember correctly - batteries anyhow). I was in a hurry so I
> > didn't take a real close look, but the front of the package seemed to
> > claim that it didn't even heat up (you couldn't burn yourself with the
> > tip). Can it boil water at room temp too? Has anyone seen one of
> > these? What gives?
> >
>
>
> ** Sounds like the same POS advertised on a shonky web site.
>
> Apparently relies on " I squared R " heating of solder in the local
> rea - rather than conduction of thermal energy.
>
> Dangerous, dodgy and stupid - to say the least.
>
> The AA cells may easily explode due to overheating if shorted - something
> all makers warn against.
>
>
>
>
> ......... Phil
>

ever try those little butane solder pencils? thay never lasted very long
before falling apart on me.
Anonymous
July 13, 2005 12:21:35 PM

Archived from groups: rec.audio.pro (More info?)

In article <11d8jba8t9d6g44@corp.supernews.com> williams@nwlink.com writes:

> The problem with the Cold Heat soldering iron is that it's suitable only for
> small connections. You're not going to melt the solder in the center
> conductor on an RG-59U connector.

We had a bunch of Heliax connectors to solder on a project a while
back and someone brought out a real resistance soldering station. It
was like a pair of large tweezers connected to a transformer. It was
much better for soldering the center conductor than a regular iron
because it didn't get any solder on the outside of the pin.


--
I'm really Mike Rivers - (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
July 13, 2005 12:56:58 PM

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TimPerry <timperry@noaspamadelphia.net> wrote:
>>
>
>ever try those little butane solder pencils? thay never lasted very long
>before falling apart on me.

I use them all the time! I have the larger Weller and the little
$50 cheapie Weller, and they have been an absolute godsend for working
on antenna towers and suspended speaker arrays. I have not had any
failure problems... what is breaking on yours?
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
July 13, 2005 5:34:10 PM

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On Tue, 12 Jul 2005 16:07:35 -0700, William Sommerwerck
<williams@nwlink.com> wrote:
> Actually, this type of soldering has been used industrially for decades.
>
> The problem with the Cold Heat soldering iron is that it's suitable only for
> small connections. You're not going to melt the solder in the center
> conductor on an RG-59U connector.
>

Model railroaders use somewhat beefier units. I don't solder my track
but the folks who do swear by them.

Gets the rail hot enough for silver solder quickly enough that the
plastic ties don't melt.

There are industrial units that can solder most anything you'd want to
solder that way.
Anonymous
July 13, 2005 5:34:11 PM

Archived from groups: rec.audio.pro (More info?)

Charles Krug <cdkrug@worldnet.att.net> wrote:
>On Tue, 12 Jul 2005 16:07:35 -0700, William Sommerwerck
><williams@nwlink.com> wrote:
>> Actually, this type of soldering has been used industrially for decades.
>>
>> The problem with the Cold Heat soldering iron is that it's suitable only for
>> small connections. You're not going to melt the solder in the center
>> conductor on an RG-59U connector.
>
>Model railroaders use somewhat beefier units. I don't solder my track
>but the folks who do swear by them.
>
>Gets the rail hot enough for silver solder quickly enough that the
>plastic ties don't melt.

This is a good application for resistance soldering. You have work
that is narrow and straight and has pretty much a constant cross-section.

Around here, Norfolk Southern used to weld their rails with thermite
compound, again because you could get a lot of heat in a small localized
place for a short time. I'm surprised the model railroad guys are not
just using resistance welding and doing little spotwelds between tracks,
sort of like that.

>There are industrial units that can solder most anything you'd want to
>solder that way.

Some things, anyway. Resistance soldering is great for things like
making tin cans and butt-welds on rod stock. It's not a good thing
at all for irregularly-shaped work.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
July 13, 2005 5:52:16 PM

Archived from groups: rec.audio.pro (More info?)

"Scott Dorsey" <kludge@panix.com> wrote in message
news:D b332q$t0o$1@panix2.panix.com...
> TimPerry <timperry@noaspamadelphia.net> wrote:
> >>
> >
> >ever try those little butane solder pencils? thay never lasted very
long
> >before falling apart on me.
>
> I use them all the time! I have the larger Weller and the little
> $50 cheapie Weller, and they have been an absolute godsend for working
> on antenna towers and suspended speaker arrays. I have not had any
> failure problems... what is breaking on yours?
> --scott
>

i haven't bothered with them since the 70s. when i need gas heat now i use
an oxy/map torch.

maybe they have improved.
Anonymous
July 14, 2005 2:19:59 AM

Archived from groups: rec.audio.pro (More info?)

Scott Dorsey <kludge@panix.com> wrote:


> Around here, Norfolk Southern used to weld their rails with thermite
> compound, again because you could get a lot of heat in a small localized
> place for a short time. I'm surprised the model railroad guys are not
> just using resistance welding and doing little spotwelds between tracks,
> sort of like that.

http://www.bathtram.org/tfb/tT49.htm


--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk
Anonymous
July 15, 2005 11:54:11 AM

Archived from groups: rec.audio.pro (More info?)

William Sommerwerck wrote:

>>Why would anyone want to purposely make a "cold solder" joint?
>
>
> My favorite part of the commercial is when the guy finishes the joint, then
> drops the iron into his pocket -- and we're told its temperature quickly
> drops from 800 to 0 degrees!
>
> In case you're not up on thermodynamics, that's impossible. Would that it
> were...

That's because the tip of the "iron" isn't actually heating up,
though... the work material heats up from the current passed through it.
The tip only heats up by what little heat transfers to it from the
material.


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Anonymous
July 15, 2005 11:54:12 AM

Archived from groups: rec.audio.pro (More info?)

>> My favorite part of the commercial is when the guy finishes the joint,
>> then drops the iron into his pocket -- and we're told its temperature
>> quickly drops from 800 to 0 degrees!
>> In case you're not up on thermodynamics, that's impossible.
>> Would that it were...

> That's because the tip of the "iron" isn't actually heating up,
> though... the work material heats up from the current passed
> through it. The tip only heats up by what little heat transfers
> to it from the material.

Please reread what the ad states and what I actually wrote.
Anonymous
July 15, 2005 11:54:12 AM

Archived from groups: rec.audio.pro (More info?)

Just thought of another point...

Nicad and NiMH cells can pump a huge amount of current into a short -- more
than an alkaline. If you get a Cold Heat, you might want to power it with
NiMHs.

Last year I got a bunch of 1800 mAh NiMHs from a major parts supplier for 50
cents apiece. Fry's sometimes has really good prices. Keep an eye out...
Anonymous
July 15, 2005 12:10:21 PM

Archived from groups: rec.audio.pro (More info?)

apa wrote:

> I was at Home Depot a few weeks ago and in one of the displays toward
> the front of the store there was a "soldering iron" that ran on AA's
> (if I remember correctly - batteries anyhow). I was in a hurry so I
> didn't take a real close look, but the front of the package seemed to
> claim that it didn't even heat up (you couldn't burn yourself with the
> tip). Can it boil water at room temp too? Has anyone seen one of
> these? What gives?

Canadian Tire sells them north of the 49th under the name "Cold Heat",
for something like $30... they have a great return policy (bring it back
with the receipt within 30 days and get a full refund, no questions
asked), so I figured I had nothing to lose.

As others have noted, the thing works by passing high current through
the work material (wire, pad, solder, etc.), thus heating the material
itself, rather than the standard method of heating the tip then
transferring the heat to the work. The tip is electrically conductive
but only very slightly heat conductive, so what little it does heat up
is only heat transferred from the work, and once removed from the heat
source, it cools off quickly.

And yes, Virginia, this little iron DOES work, with limitations... and
within those limitations, it works quite well.

First, it's only useful on relatively small jobs: soldering a splice of
two or three piece of 18ga. or smaller wire, mid-sized, well-spaced pads
on PC boards, etc. Smaller solder works better as well.

Second, both sides of the split tip have to make good contact with the
work, meaning it won't work well on dirty or oxidized surfaces (normally
after heating such surfaces, the resin or flux in the melting solder
will clean the surfaces). If soldering a wire splice, you have to make
sure the wire is well-secured so you can press the tip solidly against it.

Frankly, I've found it very useful several times, working with CCTV,
intercom and access-control systems, where most of what little soldering
I do is confined to 22ga. station wire and RG-59 (I've actually used it
to successfully solder to both RG-59 core and shield wires): I can have
three or four splices done in the same time it takes my butane iron to
heat up fully, and I can pack it away immediately, unlike the 10 mintues
it takes the butane iron to cool down enough.



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Anonymous
July 15, 2005 12:10:22 PM

Archived from groups: rec.audio.pro (More info?)

> Second, both sides of the split tip have to make good contact with the
> work, meaning it won't work well on dirty or oxidized surfaces (normally
> after heating such surfaces, the resin or flux in the melting solder
> will clean the surfaces). If soldering a wire splice, you have to make
> sure the wire is well-secured so you can press the tip solidly against it.

Good points. Hadn't thought of those.


> Frankly, I've found it very useful several times, working with CCTV,
> intercom and access-control systems, where most of what little soldering
> I do is confined to 22ga. station wire and RG-59 (I've actually used it
> to successfully solder to both RG-59 core and shield wires): I can have
> three or four splices done in the same time it takes my butane iron to
> heat up fully, and I can pack it away immediately, unlike the 10 mintues
> it takes the butane iron to cool down enough.

YouI can buy one at Costco for US$15. (The kit with the wire stripper is a
few dollers more.) Maybe I'll get one, just as a backup. But I still have my
Wahl IsoTip -- though I don't know if the nicads have dried out. When you
have a variable-temperature soldering iron, there's less need for a
low-power iron (other than its cordlessness).
Anonymous
July 15, 2005 12:11:55 PM

Archived from groups: rec.audio.pro (More info?)

TimPerry wrote:

> ever try those little butane solder pencils? thay never lasted very long
> before falling apart on me.

Maybe you've just had cheap ones then - I've got a PortaSol butane iron
that's been serving me well for over 10 years now.


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Anonymous
July 15, 2005 12:48:23 PM

Archived from groups: rec.audio.pro (More info?)

>
> As others have noted, the thing works by passing high current through
> the work material (wire, pad, solder, etc.), thus heating the material
> itself, rather than the standard method of heating the tip then
> transferring the heat to the work. The tip is electrically conductive
> but only very slightly heat conductive, so what little it does heat up
> is only heat transferred from the work, and once removed from the heat
> source, it cools off quickly.
>

Is everyone else missing this, or am I not understanding the construction
properly...

The same current is passing through the tip as is passing through the
material... unless the tip is significantly less resistive than the
material, the tip will heat just as much from the current passing through.
Anonymous
July 15, 2005 1:03:16 PM

Archived from groups: rec.audio.pro (More info?)

"David Grant" <NO_SPAM_PLEASE_jmd_2003@msn.com> wrote in
message
news:4cidnQzwXoGZLUrfRVn-sQ@rogers.com
>> As others have noted, the thing works by passing high
current
>> through the work material (wire, pad, solder, etc.), thus
>> heating the material itself, rather than the standard
method
>> of heating the tip then transferring the heat to the
work.
>> The tip is electrically conductive but only very slightly
>> heat conductive, so what little it does heat up is only
heat
>> transferred from the work, and once removed from the heat
>> source, it cools off quickly.
>>
>
> Is everyone else missing this, or am I not understanding
the
> construction properly...
>
> The same current is passing through the tip as is passing
> through the material... unless the tip is significantly
less
> resistive than the material, the tip will heat just as
much
> from the current passing through.

Good point.

I think that in fact the tips are significantly less
resistive than tin/lead solder.
Anonymous
July 15, 2005 5:19:11 PM

Archived from groups: rec.audio.pro (More info?)

"Arny Krueger" <arnyk@hotpop.com> wrote in message
news:-_mdncZXt5eOKUrfRVn-vw@comcast.com...
> "David Grant" <NO_SPAM_PLEASE_jmd_2003@msn.com> wrote in
> message
> news:4cidnQzwXoGZLUrfRVn-sQ@rogers.com
> >> As others have noted, the thing works by passing high
> current
> >> through the work material (wire, pad, solder, etc.), thus
> >> heating the material itself, rather than the standard
> method
> >> of heating the tip then transferring the heat to the
> work.
> >> The tip is electrically conductive but only very slightly
> >> heat conductive, so what little it does heat up is only
> heat
> >> transferred from the work, and once removed from the heat
> >> source, it cools off quickly.
> >>
> >
> > Is everyone else missing this, or am I not understanding
> the
> > construction properly...
> >
> > The same current is passing through the tip as is passing
> > through the material... unless the tip is significantly
> less
> > resistive than the material, the tip will heat just as
> much
> > from the current passing through.
>
> Good point.
>
> I think that in fact the tips are significantly less
> resistive than tin/lead solder.
>
>

Which means the tip would have to be a significantly better conductor than
solder... Silver? but that's a pretty darn good thermal conductor too.
Anonymous
July 15, 2005 6:12:23 PM

Archived from groups: rec.audio.pro (More info?)

"David Grant" <NO_SPAM_PLEASE_jmd_2003@msn.com> wrote in
message
news:F56dneWBvIXhckrfRVn-gw@rogers.com
> "Arny Krueger" <arnyk@hotpop.com> wrote in message
> news:-_mdncZXt5eOKUrfRVn-vw@comcast.com...
>> "David Grant" <NO_SPAM_PLEASE_jmd_2003@msn.com> wrote in
>> message
>> news:4cidnQzwXoGZLUrfRVn-sQ@rogers.com
>>>> As others have noted, the thing works by passing high
>> current
>>>> through the work material (wire, pad, solder, etc.),
thus
>>>> heating the material itself, rather than the standard
>> method
>>>> of heating the tip then transferring the heat to the
>> work.
>>>> The tip is electrically conductive but only very
slightly
>>>> heat conductive, so what little it does heat up is only
>> heat
>>>> transferred from the work, and once removed from the
heat
>>>> source, it cools off quickly.
>>>>
>>>
>>> Is everyone else missing this, or am I not understanding
>> the
>>> construction properly...
>>>
>>> The same current is passing through the tip as is
passing
>>> through the material... unless the tip is significantly
>> less
>>> resistive than the material, the tip will heat just as
>> much
>>> from the current passing through.
>>
>> Good point.
>>
>> I think that in fact the tips are significantly less
>> resistive than tin/lead solder.

> Which means the tip would have to be a significantly
better
> conductor than solder... Silver? but that's a pretty darn
good
> thermal conductor too.

Tin/lead alloys are not very good conductors compared to
copper.

Reference:
http://www.eddy-current.com/condres.htm

Pure copper has resistivity of 1.664E-08 ohm-meters while
the
resistivity of 50-50 tin-lead solder is 1.567E-07
ohm-meters.

IOW pure copper is about 10 times as electrically conductive
as regular tin-lead solder.
July 15, 2005 7:36:58 PM

Archived from groups: rec.audio.pro (More info?)

In article <11df8kpiqubioad@corp.supernews.com>, "William Sommerwerck" <williams@nwlink.com> wrote:
>Just thought of another point...
>
>Nicad and NiMH cells can pump a huge amount of current into a short -- more
>than an alkaline. If you get a Cold Heat, you might want to power it with
>NiMHs.

NiMH's have more internal resistans than Nicads. Best to use Nicads
for high current.

greg

>Last year I got a bunch of 1800 mAh NiMHs from a major parts supplier for 50
>cents apiece. Fry's sometimes has really good prices. Keep an eye out...
>
>
Anonymous
July 15, 2005 7:36:59 PM

Archived from groups: rec.audio.pro (More info?)

"GregS" <szekeres@pitt.edu> wrote in message
news:D b8l7o$a24$1@usenet01.srv.cis.pitt.edu
> In article <11df8kpiqubioad@corp.supernews.com>, "William
> Sommerwerck" <williams@nwlink.com> wrote:
>> Just thought of another point...
>>
>> Nicad and NiMH cells can pump a huge amount of current
into a
>> short -- more than an alkaline. If you get a Cold Heat,
you
>> might want to power it with NiMHs.
>
> NiMH's have more internal resistans than Nicads. Best to
use
> Nicads
> for high current.

I hear tell that NiMH's also have built in current limiters.
Something about exploding without them when shorted.
Anonymous
July 15, 2005 10:22:01 PM

Archived from groups: rec.audio.pro (More info?)

On Fri, 15 Jul 2005 13:19:11 -0400, "David Grant"
<NO_SPAM_PLEASE_jmd_2003@msn.com> wrote:

>> I think that in fact the tips are significantly less
>> resistive than tin/lead solder.
>>
>>
>
>Which means the tip would have to be a significantly better conductor than
>solder... Silver? but that's a pretty darn good thermal conductor too.
>

60/40 Tin Lead solder is nearly ten times the resistivity of pure
copper, so there would really be no problem in focussing the heat into
the work piece.

d

Pearce Consulting
http://www.pearce.uk.com
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