What sucks about flux

C

Chris Carlen

Guest
Hi:

I have obtained a sample quantity of something closely resembling
unobtainium.

It is lead-free solder with a melting point of 217C, cored with
activated rosin flux. CASTIN alloy from Aim, with composition
Sn96.5Ag2.5Cu0.5Sb0.5

Aim claims that the wetting action of SAC type alloys decreases with
increasing Ag content, and that the 2.5% Ag gives a more optimum wetting
than 3.0% Ag typical of SAC305 which is likely to be the industry
standard lead-free.

They implicate Motorola in having a lot to do with the choice of SAC305,
though the fact that CASTIN is patented probably doesn't help.

Also, the 0.5% antimony helps to keep grain size consistent over a range
of cooling rates which is a large plus for an alloy to be used in hand
soldering/rework. Slow cooling tends to cause large grain sizes,
resulting in the very frosty appearance of lead-free solder joints.

If you have experimented with any SAC305 hand soldering, you will
discover that it is possible for the alloy to harden to a shiny joint,
but the cooling must occur at a very rapid rate, and having a lot of
flux helps as well.

The CASTIN's antimony content seems to help make the frosty surface
remain as finely grained as possible, and also if a cross section of the
joint is examined under a microscope, the CASTIN is more homogeneous
with respect to grain size, whereas non-Sb bearing SAC alloys are much
more heterogeneous. Thus CASTIN could be expected to deliver more
consistent joint strength in non-automated soldering methods.

In my initial experiments with the RA-cored CASTIN, I am greatly
impressed by how well it wets and flows, as well as its tendency to give
a more mildly frosty surface appearance than what often results with SAC305.

I think it is the RA flux though, not just the alloy composition that
leads to the very good wetting action of RA-cored CASTIN. But perhaps
the two factors together are as close to a optimum lead-free as is
possible to achieve. It really is not much different from working with
Sn60Pb40.

However, due to market forces, it appears likely that we will not see
rosin cored lead-free wire solders available in the future. At least
not from Aim, but they seem to think that this will be the case
throughout the solder industry. They don't want such a large matrix of
flux/alloy combinations, so they want to stock only no-clean and
water-clean flux cored wire solders.

I think this sucks, partly because for all the non-automated soldering
that goes on out there, rosin is something that people are familiar
with. Even just the smell. No-clean smells like a burning chemical
stink, whereas rosin is quite pleasant. (At least for those of us who
don't suffer allergic reaction to rosin.)

But I am convinced that rosin is a better flux, compared at least to the
no-cleans that I have had the opportunity to try. I like the RA CASTIN
wire *much* better than my Kester no-clean SAC305 wire. When I add some
rosin to a joint prior to soldering with SAC305, then it performs much
better. But I don't want to have to dispense bonus flux to ever joint I
perform. That's the point of flux core in the first place. The fact
that no-clean wires tend not to have more than 2% flux, where RA may be
up to 3%, may also be a factor.

Oh well.

It is actually possible to custom order CASTIN with RA flux, but one
would have to order 24 lbs. Hmm, that makes me wonder: Is anyone
interested in a group purchase of 0.031" RA cored CASTIN wire? I
suppose if we could get it down to 1-2 rolls per person, it might not be
a bad deal. Or maybe I should swing for 24 rolls and sell the surplus
on Ebay.

I hope that there will ultimately wind up to be RA cored SAC305 wires
available in the future, when the RoHS misfortune has fully taken hold.
Perhaps the manufacturers will get enough complaints from folks who
are just used to rosin and its pleasant smell to stock it despite their
present judgements of the market.


Good day!






--
_____________________
Christopher R. Carlen
crobc@bogus-remove-me.sbcglobal.net
SuSE 9.1 Linux 2.6.5
 
On Sun, 07 Aug 2005 09:36:19 -0700, Chris Carlen
<crobc@BOGUSFIELD.sbcglobal.net> wrote:

Hi:

I have obtained a sample quantity of something closely resembling
unobtainium.

[snip]

Is Sn/Pb solder still available for purchase?

I have a fairly good-sized spool, but I guess I'd better salt away
15-20 years supply, for my G-jobs.

That will hold me to age 80-85 ;-)

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
In the high temperature Kestor Sn96.5 Ag2.5 Cu0.5 with #44 flux has been in
use for decades and there had not been a major issue with workability once
you get used to the higher temepratures. It wets better than any other high
temeperature solder we tried. It is a bit brittle and with a couple of
theremal cycles (0-180C) (thats right C) it will fatigue and fail on fine
pitched solder joints. SOIC and dip joints are fine. It also does very well
for 0-125C thermal cycles so for commercial temps it should be ideal.

Use small diameter wire with hand soldering (0.020"-0.030") and get off the
joint quick.
 
Jim Thompson wrote:
On Sun, 07 Aug 2005 09:36:19 -0700, Chris Carlen
crobc@BOGUSFIELD.sbcglobal.net> wrote:

Hi:

I have obtained a sample quantity of something closely resembling
unobtainium.

[snip]

Is Sn/Pb solder still available for purchase?

I have a fairly good-sized spool, but I guess I'd better salt away
15-20 years supply, for my G-jobs.

That will hold me to age 80-85 ;-)
You know of course that RoHS is so far only a Euro regulatory
boondoggle, and hasn't yet been manifested here in any binding manner.

The electronics and electronics tools catalogs are still filled with
lots of SnPb solders, so I think you can get what you want for some
time. I would recommend Kester. I had some Radio Shack solder that
went bad or maybe sucked all along. Some sections of the wire were
almost entirely empty of flux. So I invested in 4 rolls of Kester 44 in
0.015", 0.025", and 0.031" Sn63Pb37 (eutectic is wonderful for PCB
assembly since it flows and hardens almost instantly), and 0.050"
Sn60Pb40 a while back for home use. Now I'm interested in Pb-free just
for the sake of my baby.

But as an eccentric I also tend to like doing things differently, and so
there is an allure of the "exoticness" of Pb-free solders. But that's
just a personality thing. And being a chemist, we can have peculiar
fascinations with the elements, that non-chemists tend to find
incomprehensible. For myself, that elemental fascination has been with
silver ever since I was a kid. So using silver bearing solder is a lot
of fun!

Good day!




--
_____________________
Christopher R. Carlen
crobc@bogus-remove-me.sbcglobal.net
SuSE 9.1 Linux 2.6.5
 
Mook Johnson wrote:
In the high temperature Kestor Sn96.5 Ag2.5 Cu0.5 with #44 flux has been in
use for decades and there had not been a major issue with workability once
you get used to the higher temepratures. It wets better than any other high
temeperature solder we tried. It is a bit brittle and with a couple of
theremal cycles (0-180C) (thats right C) it will fatigue and fail on fine
pitched solder joints. SOIC and dip joints are fine. It also does very well
for 0-125C thermal cycles so for commercial temps it should be ideal.

Use small diameter wire with hand soldering (0.020"-0.030") and get off the
joint quick.
Interesting. First of all, your alloy doesn't add up to 100%. Is it
really Sn96.5 Ag3.0 Cu0.5?

There are also alloys such as Sn96Ag4 which are higher melting than SAC305.

I will have to call Kester Monday, since in their PDF catalogs, they
don't indicate a 44 cored lead-free wire.


Thanks for the input.


Good day!




--
_____________________
Christopher R. Carlen
crobc@bogus-remove-me.sbcglobal.net
SuSE 9.1 Linux 2.6.5
 
On Sun, 07 Aug 2005 11:08:00 -0700, Chris Carlen
<crobc@BOGUSFIELD.sbcglobal.net> wrote:



You know of course that RoHS is so far only a Euro regulatory
boondoggle, and hasn't yet been manifested here in any binding manner.

It's interesting that they exempted the telecom industry, and that in
Europe most of the telecoms are owned by the government.

Something like 1% of the lead in commercial use is in electronics, and
that's in solid metal or glass, nearly insoluble forms. What are they
doing about car batteries, where massive amounts of nasty lead
compounds are present?

John
 
John Larkin wrote:

Something like 1% of the lead in commercial use is in electronics, and
that's in solid metal or glass, nearly insoluble forms. What are they
doing about car batteries, where massive amounts of nasty lead
compounds are present?

Truly -- they should switch to Nickel Cadmium (duck and cover).

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
 
John Larkin wrote:

On Sun, 07 Aug 2005 11:08:00 -0700, Chris Carlen
crobc@BOGUSFIELD.sbcglobal.net> wrote:

You know of course that RoHS is so far only a Euro regulatory
boondoggle, and hasn't yet been manifested here in any binding manner.

It's interesting that they exempted the telecom industry, and that in
Europe most of the telecoms are owned by the government.
That's an outfated view.

Euro regulation has actually put former State companies in to the *private
sector*.

Something like 1% of the lead in commercial use is in electronics, and
that's in solid metal or glass, nearly insoluble forms. What are they
doing about car batteries, where massive amounts of nasty lead
compounds are present?
They of course are exempt. lol :-(


Graham
 
"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in
message news:jencf1t5603ko8bralokg40ouh6m45ln6u@4ax.com...
On Sun, 07 Aug 2005 11:08:00 -0700, Chris Carlen
crobc@BOGUSFIELD.sbcglobal.net> wrote:



You know of course that RoHS is so far only a Euro regulatory
boondoggle, and hasn't yet been manifested here in any binding manner.


It's interesting that they exempted the telecom industry, and that in
Europe most of the telecoms are owned by the government.

Something like 1% of the lead in commercial use is in electronics, and
that's in solid metal or glass, nearly insoluble forms. What are they
doing about car batteries, where massive amounts of nasty lead
compounds are present?

John
Key thing about RoHs, is that it is aimed at just one thing. Electronic
rubbish that goes into the waste tip. The assumption at present, is that
lead-acid batteries for example, already have a seperate 'bin' at the
dump. Similarly, lead solders used in plumbing, end up going to the metal
recycling yard, because the plumber can make money from the copper. They
did a fairly simple analysis of what contained lead in a typical council
dump, and most of it was the solder in cheap consumer electronics being
thrown away.
The 'idea' then makes sense. Whether it'll actually work, and the
implications on reliability as people try to cut corners on th substitute
materials, we will know in a few decades...

Best Wishes
 
Roger Hamlett wrote:

Key thing about RoHs, is that it is aimed at just one thing. Electronic
rubbish that goes into the waste tip. The assumption at present, is that
lead-acid batteries for example, already have a seperate 'bin' at the
dump. Similarly, lead solders used in plumbing, end up going to the metal
recycling yard, because the plumber can make money from the copper. They
did a fairly simple analysis of what contained lead in a typical council
dump, and most of it was the solder in cheap consumer electronics being
thrown away.
The 'idea' then makes sense. Whether it'll actually work, and the
implications on reliability as people try to cut corners on th substitute
materials, we will know in a few decades...
Except it doesn't make sense because of WEEE.

WEEE want to keep electronics out of the general trash. So we'll end up
making lead free product ( or not ) so it *can* be put in the trash but WEEE
says it mustn't be put in the trash anyway !

See the 'crossed out wheelie bin' logo.

http://uk.farnell.com/static/en/rohs/news/wheelie_label.htm

Talk about the left and right hand not knowing what they're doing.

Graham
 
On Sun, 07 Aug 2005 11:08:00 -0700, the renowned Chris Carlen
<crobc@BOGUSFIELD.sbcglobal.net> wrote:

So I invested in 4 rolls of Kester 44 in
0.015", 0.025", and 0.031" Sn63Pb37 (eutectic is wonderful for PCB
assembly since it flows and hardens almost instantly), and 0.050"
Sn60Pb40 a while back for home use.
Does anyone have a particular preference on alloy for hand-soldering
fairly fine-pitch (0.5mm) parts?


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
 
Something like 1% of the lead in commercial use is in electronics, and
that's in solid metal or glass, nearly insoluble forms. What are they
doing about car batteries, where massive amounts of nasty lead
compounds are present?


Car batteries are not ending up in the waste generated by households. In
fact there exists a well established and well functioning recycling
industry for car batteries. In some countries you even have to pay a
significant deposit when buying a new battery, which is returned once
you return the old battery to the dealer for recycling.
RoHS' target is the large fraction of consumer electronics, which ends
up in the household garbage. You got a new cell phone, the old one is
thrown into the trash can. Your CD-ROM fails, you get a new one and the
old goes in the trash can. There are so many cheap, low cost, short
life-time, everyday electronic gadgets, that most of it, just ends up in
either the land fill or an incinerator like kitchen scrap.
Previous attempts to educate people to return their used electronics to
special collections sites have largely failed. Although lead free solder
is certainly a manufacturing problem, I think RoHS is reasonable.
Basically I don't think that RoHS is a bigger manufacturing problem then
the introduction of say SMDs, BGAs, multilayer PCBs etc. It's annoying
fo now, but we will get used to it ...

Klaus
 
This page may be interesting reading for what we are doing in the down hole,
high temeprature market.

http://www.logwell.com/tech/servtips/solder.html




"Chris Carlen" <crobc@BOGUSFIELD.sbcglobal.net> wrote in message
news:dd5k9c02qp5@news1.newsguy.com...
Mook Johnson wrote:
In the high temperature Kestor Sn96.5 Ag2.5 Cu0.5 with #44 flux has been
in use for decades and there had not been a major issue with workability
once you get used to the higher temepratures. It wets better than any
other high temeperature solder we tried. It is a bit brittle and with a
couple of theremal cycles (0-180C) (thats right C) it will fatigue and
fail on fine pitched solder joints. SOIC and dip joints are fine. It
also does very well for 0-125C thermal cycles so for commercial temps it
should be ideal.

Use small diameter wire with hand soldering (0.020"-0.030") and get off
the joint quick.

Interesting. First of all, your alloy doesn't add up to 100%. Is it
really Sn96.5 Ag3.0 Cu0.5?

There are also alloys such as Sn96Ag4 which are higher melting than
SAC305.

I will have to call Kester Monday, since in their PDF catalogs, they don't
indicate a 44 cored lead-free wire.


Thanks for the input.


Good day!




--
_____________________
Christopher R. Carlen
crobc@bogus-remove-me.sbcglobal.net
SuSE 9.1 Linux 2.6.5
 
Spehro Pefhany wrote:
On Sun, 07 Aug 2005 11:08:00 -0700, the renowned Chris Carlen
crobc@BOGUSFIELD.sbcglobal.net> wrote:

So I invested in 4 rolls of Kester 44 in
0.015", 0.025", and 0.031" Sn63Pb37 (eutectic is wonderful for PCB
assembly since it flows and hardens almost instantly), and 0.050"
Sn60Pb40 a while back for home use.

Does anyone have a particular preference on alloy for hand-soldering
fairly fine-pitch (0.5mm) parts?
I will be once again looking at pastes for SMD stuff in the near future.
I tried PbSn paste when I first learned to solder SMD, applying it
with a syringe. It was very hard to get consistent quantities that way.

Then I switched to 0.015" Kester Sn63Pb37 with liquid RA flux pen. That
works quite nice.

But I am not sure I want to continue with wire and SMD with Pb-free.
Not sure why. Actually, I'll probably continue, but I would like to
learn more about application methods for paste.

Anyway, it looks like SAC305 will ultimately be the standard for most
everything.

Good day!



--
_____________________
Christopher R. Carlen
crobc@bogus-remove-me.sbcglobal.net
SuSE 9.1 Linux 2.6.5
 
On Sun, 07 Aug 2005 17:20:22 -0700, the renowned Chris Carlen
<crobc@BOGUSFIELD.sbcglobal.net> wrote:

Spehro Pefhany wrote:
On Sun, 07 Aug 2005 11:08:00 -0700, the renowned Chris Carlen
crobc@BOGUSFIELD.sbcglobal.net> wrote:

So I invested in 4 rolls of Kester 44 in
0.015", 0.025", and 0.031" Sn63Pb37 (eutectic is wonderful for PCB
assembly since it flows and hardens almost instantly), and 0.050"
Sn60Pb40 a while back for home use.

Does anyone have a particular preference on alloy for hand-soldering
fairly fine-pitch (0.5mm) parts?

I will be once again looking at pastes for SMD stuff in the near future.
I tried PbSn paste when I first learned to solder SMD, applying it
with a syringe. It was very hard to get consistent quantities that way.

Then I switched to 0.015" Kester Sn63Pb37 with liquid RA flux pen. That
works quite nice.
The reason I ask is that I changed from 60/40 to 63/37 as a roll ran
out and it has not gone nearly as smoothly as usual on the latest
prototypes.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
 
Hello Chris,

It is lead-free solder with a melting point of 217C, cored with
activated rosin flux. CASTIN alloy from Aim, with composition
Sn96.5Ag2.5Cu0.5Sb0.5
Antimony:
http://www.epa.gov/ttnatw01/hlthef/antimony.html

This whole ROHS is typical overblown knee jerk legislation, probably
concocted by people who know little about the long term impact of their
actions. Who knows, maybe 10-20 years from now they have to go through
their "oh s..t" phase when miscarriage rates jump up or other effects
happen.

We have just been through one of those routines with MTBE.

Regards, Joerg

http://www.analogconsultants.com
 
Hello John,

You know of course that RoHS is so far only a Euro regulatory
boondoggle, and hasn't yet been manifested here in any binding manner.

It's interesting that they exempted the telecom industry, and that in
Europe most of the telecoms are owned by the government.
IIRC that includes network equipment. So, what if your latest super
widget simply contained a cheap jack with serial port signals that talks
Klingon? Wouldn't that make it exempt? Maybe nobody says that whatever
is on that "network interface" has to be intelligible ;-)

Something like 1% of the lead in commercial use is in electronics, and
that's in solid metal or glass, nearly insoluble forms. What are they
doing about car batteries, where massive amounts of nasty lead
compounds are present?
In Europe car batteries are usually recylced. But not all of them. Worse
are other lead sources. As an example many roofs over there contain one
or two "lead tiles". They are used where antenna poles feed through the
roof line. In contrast to the plastic contraptions these do not weather
out and become brittle. When someone re-roofs this stuff just gets
tossed IIRC.

Regards, Joerg

http://www.analogconsultants.com
 
Joerg wrote:

Hello John,

You know of course that RoHS is so far only a Euro regulatory
boondoggle, and hasn't yet been manifested here in any binding manner.

It's interesting that they exempted the telecom industry, and that in
Europe most of the telecoms are owned by the government.

IIRC that includes network equipment.
Actually, networking stuff is also exempted but under a separate category
entirely.

As also are servers ( and presumably related stuff like hard drives ).


So, what if your latest super
widget simply contained a cheap jack with serial port signals that talks
Klingon? Wouldn't that make it exempt? Maybe nobody says that whatever
is on that "network interface" has to be intelligible ;-)
It has been suggested that to 'evade' RoHS, all a PC mobo has to do is
ensure that an integrated ethernet port is included. I bet that'll be what
happens too.


Something like 1% of the lead in commercial use is in electronics, and
that's in solid metal or glass, nearly insoluble forms. What are they
doing about car batteries, where massive amounts of nasty lead
compounds are present?

In Europe car batteries are usually recylced. But not all of them. Worse
are other lead sources. As an example many roofs over there contain one
or two "lead tiles". They are used where antenna poles feed through the
roof line. In contrast to the plastic contraptions these do not weather
out and become brittle. When someone re-roofs this stuff just gets
tossed IIRC.
I've never seen one of those ( lead tiles ) . Poles are often mounted on a
chimney or maybe otherwise to the brick ( or other ) structure.

Lead is used for 'flashing' on roofs though. And in roof 'gulleys' and
'valleys'.The only stuff that lasts.

Graham
 
I have obtained a sample quantity of something closely resembling
unobtainium.

It is lead-free solder with a melting point of 217C, cored with
activated rosin flux. CASTIN alloy from Aim, with composition
Sn96.5Ag2.5Cu0.5Sb0.5

I bought a roll of lead-free solder from Radiospares (Ecosol TSC 96SC
Sn95.5Ag3.8Cu0.7, 217°C) more than a year ago (maybe even two) and never got
to using it because it really smells bad when hot, a nasty
better-put-on-a-mask kind of smell. And it only works well on lead-free
pcbs.

-- John
 
On Mon, 08 Aug 2005 10:33:38 GMT, Joerg
<notthisjoergsch@removethispacbell.net> wrote:

Hello Chris,

It is lead-free solder with a melting point of 217C, cored with
activated rosin flux. CASTIN alloy from Aim, with composition
Sn96.5Ag2.5Cu0.5Sb0.5

Antimony:
http://www.epa.gov/ttnatw01/hlthef/antimony.html

This whole ROHS is typical overblown knee jerk legislation, probably
concocted by people who know little about the long term impact of their
actions. Who knows, maybe 10-20 years from now they have to go through
their "oh s..t" phase when miscarriage rates jump up or other effects
happen.
Wonder what long term exposure to antimony does to your brain ?:)

We have just been through one of those routines with MTBE.
Which, AIUI, goes out of production very soon.

Regards, Joerg

http://www.analogconsultants.com

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 

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