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Recognizing lead-free solder

M

mc

Jan 1, 1970
0
Given that it's desirable to do repairs with the same type of solder as was
used originally, in order to avoid alloy mixing or partial melting
problems...

(1) How do I recognize lead-free solder when I see it?

(2) What temperature should I set my iron to, when working with SnSb or SnAg
solder?

Thanks!
 
P

Pooh Bear

Jan 1, 1970
0
mc said:
Given that it's desirable to do repairs with the same type of solder as was
used originally, in order to avoid alloy mixing or partial melting
problems...

(1) How do I recognize lead-free solder when I see it?
Click to expand...

Gawd knows mate. The politicians probably didn't think of that one.
(2) What temperature should I set my iron to, when working with SnSb or SnAg
solder?
Click to expand...

About 50C higher. Hang on, you said " SnSb or SnAg " ! Where do you think you're
going to find those ?

Graham
 
G

g. beat

Jan 1, 1970
0
mc said:
Given that it's desirable to do repairs with the same type of solder as
was used originally, in order to avoid alloy mixing or partial melting
problems...

(1) How do I recognize lead-free solder when I see it?

(2) What temperature should I set my iron to, when working with SnSb or
SnAg solder?

Thanks!
Click to expand...
Georgia ?

How about starting with an Alloy Temperature Chart??
http://www.kester.com/en-us/technical/alloy.aspx

Kester Lead Free Solutions
http://www.kester.com/en-us/leadfree/index.aspx


NPL: UK's National Measurement Labs
http://www.npl.co.uk/ei/research/leadfree.html
 
G

g. beat

Jan 1, 1970
0
mc said:
Given that it's desirable to do repairs with the same type of solder as
was used originally, in order to avoid alloy mixing or partial melting
problems...

(1) How do I recognize lead-free solder when I see it?

(2) What temperature should I set my iron to, when working with SnSb or
SnAg solder?

Thanks!
Click to expand...
BTW, Kester lists 5 eutectic solder alloys on this chart -- can you find
them?
http://www.kester.com/en-us/technical/alloy.aspx

http://en.wikipedia.org/wiki/Eutectic
 
A

Arfa Daily

Jan 1, 1970
0
mc said:
Given that it's desirable to do repairs with the same type of solder as
was used originally, in order to avoid alloy mixing or partial melting
problems...

(1) How do I recognize lead-free solder when I see it?

(2) What temperature should I set my iron to, when working with SnSb or
SnAg solder?

Thanks!
Click to expand...
It has been recommended by the creators of the half-arsed RoHS directive,
that manufacturers mark their boards with the alloy that has been used. To
date, I think I have probably seen about 2 or 3. In general, boards made
with lead-free, look as though every joint is bad ( and often, this is
pretty much the case !! ). Instead of the joints having a shiny appearance,
and being domed or meniscus-shaped, they are dull and grey, decidedly
'crystalline' looking, and tend to be volcano-shaped, with straight sides.

Pretty much any commercial equipment from the big far east manufacturers -
Pan, Sony, Hitachi etc - built in the last two or so years, can be assumed
to have been built in lead-free.

When you get a lead-free board for repair, as well as finding your fault,
which may well be joint-related, check the solder joints on anything large
such as connectors, power transistors, heatsinks etc. It's also worth
checking the soldering on any LSIs fitted to the board - particularly the
rows of legs on the downstream side of the soldering process, which is often
marked on the board by an arrow. Give anything suspicious, a good rocking.
Bad joints just don't look the same as with leaded solder. I have had
components just come out in my hand, leaving behind a perfect-looking
volcano of solder. This is because the manufacturers run their solder
process plants at as low a temperature as they can, to avoid damage to LSIs
etc. With the known inferior wetting properties of lead-free, this tends to
result in insufficient heat to properly solder components with a high
thermal inertia. SM LSIs seem to suffer as a result of the inferior flowing
properties of lead-free, resulting in poorer capilliary 'draw-in' of the
solder, under the legs.

As Graham says in this thread, 50 deg C hotter is about right. The
difference in actual melting temperature, is around 30 - 40 deg, depending
on the exact mix. As a matter of interest, the recommended alloy for general
bench rework, is Tin-Copper-3% Silver. This has a melting point about 10 deg
lower, and apparently, rather better wetting properties, but I can't vouch
for this, not having tried any yet.

Arfa
 
I

ian field

Jan 1, 1970
0
mc said:
Given that it's desirable to do repairs with the same type of solder as
was used originally, in order to avoid alloy mixing or partial melting
problems...

(1) How do I recognize lead-free solder when I see it?

(2) What temperature should I set my iron to, when working with SnSb or
SnAg solder?

Thanks!
Click to expand...

Dead easy - lead free solder joints fall apart in less than a year!!!
 
I

ian field

Jan 1, 1970
0
Arfa Daily said:
It has been recommended by the creators of the half-arsed RoHS directive,
that manufacturers mark their boards with the alloy that has been used. To
date, I think I have probably seen about 2 or 3. In general, boards made
with lead-free, look as though every joint is bad ( and often, this is
pretty much the case !! ). Instead of the joints having a shiny
appearance, and being domed or meniscus-shaped, they are dull and grey,
decidedly 'crystalline' looking, and tend to be volcano-shaped, with
straight sides.
Click to expand...

<snip>

Any chance the half-arsed RoHS directive was thought up by the stuck up gits
who pepper the countryside with 12bore lead shot?
 
G

g. beat

Jan 1, 1970
0
mc said:
Actually, that gives the melting points, which weren't hard to find in the
first place. What I'm looking for is advice about how to set the
temperature-controlled iron.
Click to expand...

OK. You mean the mind-less idiot knob on the current soldering stations?

Personally my range is 650 to 750 degree -- the KEY is to stay in the range
and then select the proper tip SIZE (1/64" to 1/4" in 1/32 or 1/64"
increments) and PROFILE (screwdriver, conical, single flat) -- as well as
solder. Works well for 63/37 Tin/Lead eutectic and 60/40 alloy.

For the Weller WTCP, I still use 700 degree F tips, PTA, PTB for
screwdriver, the other 3 tips that I occasionally use depending upon the
work (reach, SMD, etc) are: PTH, PTL, PTS

I do know some people who jump to 800 degree for the no-leads -- depending
upon formulation being used.

For Lead free solder, call Alpha/Cookson Electronics (Jersey City, NJ) and
have them send you a sample of:

96.5% TIN; 3% SILVER and 0.5% COPPER in the
..020 diameter either with a 3.3% flux or WRAP2 flux


g. beat
 
A

Arfa Daily

Jan 1, 1970
0
ian field said:
<snip>

Any chance the half-arsed RoHS directive was thought up by the stuck up
gits who pepper the countryside with 12bore lead shot?
Click to expand...
Most shot used in clay shooting is no longer lead, I seem to recall. Anyway,
the point is that if it is, it is not recycled, so remains lying where it
is. Solder accounts for less than 1% of the world's mined lead, over 80%
going to car battery manufacture. The car battery industry have managed to
organise virtually 100% safe recycling, so are allowed to carry on using
lead on this basis, and the contention that there is no suitable
alternative. With the coming of the WEEE directive shortly, end of life
electronic equipment will have to be safely recycled in much the same way,
so where's the difference ? If the car battery people can do it, I'm sure
that the electronic people can also do it with less than 1/80th the volume.

The point about the RoHS directive as it stands with regard to leaded
solder, is that it is forcing a changeover from a mature, tried and tested
technology, which had reached the point of almost perfect reliability, to a
less than satisfactory alternative, with at best, woolly reasoning to try to
justify it. This is well understood by such people as the US military, who
refuse to use the stuff, the avionics industry, who have obtained
exemptions, and the medical instrument industry, likewise. Any ecological
advantage from the poisoning angle, will probably be outweighed in the long
run by the additional energy budget worldwide to run all those solder
production lines and hand soldering irons 50 degrees hotter, and all the
extra recycling brought about by electronic equipment being junked earlier
due to owners getting fed up with all the intermittent problems from bad
joints ...

Just keep your fingers crossed that avionics are not finally forced down
that route, coz that'll be the day that I stop flying.

Arfa
 
I

ian field

Jan 1, 1970
0
Arfa Daily said:
Most shot used in clay shooting is no longer lead, I seem to recall.
Anyway, the point is that if it is, it is not recycled, so remains lying
where it is. Solder accounts for less than 1% of the world's mined lead,
over 80% going to car battery manufacture. The car battery industry have
managed to organise virtually 100% safe recycling, so are allowed to carry
on using lead on this basis, and the contention that there is no suitable
alternative. With the coming of the WEEE directive shortly, end of life
electronic equipment will have to be safely recycled in much the same way,
so where's the difference ? If the car battery people can do it, I'm sure
that the electronic people can also do it with less than 1/80th the
volume.

The point about the RoHS directive as it stands with regard to leaded
solder, is that it is forcing a changeover from a mature, tried and tested
technology, which had reached the point of almost perfect reliability, to
a less than satisfactory alternative, with at best, woolly reasoning to
try to justify it. This is well understood by such people as the US
military, who refuse to use the stuff, the avionics industry, who have
obtained exemptions, and the medical instrument industry, likewise. Any
ecological advantage from the poisoning angle, will probably be outweighed
in the long run by the additional energy budget worldwide to run all those
solder production lines and hand soldering irons 50 degrees hotter, and
all the extra recycling brought about by electronic equipment being junked
earlier due to owners getting fed up with all the intermittent problems
from bad joints ...

Just keep your fingers crossed that avionics are not finally forced down
that route, coz that'll be the day that I stop flying.

Arfa
Click to expand...

Some good points there, I didn't know lead was no longer used for 12bore
shot - any idea what they use instead?

Regardless of the WEEE directive, lead was originally mined out of the
ground and one way or another it will eventually end up back there, also I
had always held the opinion that the common solder alloys were substantially
less toxic than lead on its own, if this is true then the manufacture of
lead/tin solder actually reduces the availability of lead wherever it ends
up at end of life.

One thing I have been trying to find out if anyone knows, is how much lead
the petroleum industry procured annually for TEL additives before leaded
petrol was discontinued, the figures I read somewhere (can't remember where,
or how much!) were huge - thousands of tons of lead converted into exhaust
particulates to be inhaled, washed onto agricultural land and into the water
table, I suspect that lead in solder is insignificant compared to previous
usage of TEL!
 
F

Franc Zabkar

Jan 1, 1970
0
Most shot used in clay shooting is no longer lead, I seem to recall. Anyway,
the point is that if it is, it is not recycled, so remains lying where it
is. Solder accounts for less than 1% of the world's mined lead, over 80%
going to car battery manufacture. The car battery industry have managed to
organise virtually 100% safe recycling, so are allowed to carry on using
lead on this basis, and the contention that there is no suitable
alternative. With the coming of the WEEE directive shortly, end of life
electronic equipment will have to be safely recycled in much the same way,
so where's the difference ? If the car battery people can do it, I'm sure
that the electronic people can also do it with less than 1/80th the volume.
Click to expand...

I wonder how much lead is in a typical CRT? BTW, I googled for "lead
free CRT" but got very few hits.

- Franc Zabkar
 
J

Jim Land

Jan 1, 1970
0
One thing I have been trying to find out if anyone knows, is how much
lead the petroleum industry procured annually for TEL additives before
leaded petrol was discontinued, the figures I read somewhere (can't
remember where, or how much!) were huge - thousands of tons of lead
converted into exhaust particulates to be inhaled, washed onto
agricultural land and into the water table, I suspect that lead in
solder is insignificant compared to previous usage of TEL!
Click to expand...

Yes, but the lead coming out of tailpipes was widely distributed in the
air, whereas electronics that wind up in landfill dumps just sit there
for a long time and continuously leach their chemicals into the nearby
ground, whence it flows down into water tables and gets into drinking
water. I'd prefer my drinking water lead-free, thank you.
 
A

Arfa Daily

Jan 1, 1970
0
Franc Zabkar said:
I wonder how much lead is in a typical CRT? BTW, I googled for "lead
free CRT" but got very few hits.

- Franc Zabkar
Click to expand...

First to Jim two posts above. You are missing the point. The electronic
waste will no longer sit in landfill, because the new WEEE directive, in
Europe at least, will make sure that the equipment is recycled, and any lead
content removed. Electronic equipment in landfill will soon become a thing
of the past. Anyway, just how soluble is lead in water ? I'm not too sure,
but I expect some clever chemistry graduate will tell us. In the past, water
was delivered to all households in the UK via lead pipes. In a lot of older
properties, it still is. Certainly, the house that I grew up in had lead
pipework. I am not aware of people of my generation all dying of lead
poisoning, or having suffered intelligence lowering due to lead-induced
brain damage. In fact, since lead piping has been being removed here, the
kids have been getting progressively thicker ... !! I have heard people say
that delivering water via lead pipes is of no consequence, because the pipes
quickly get an internal coating of limescale, that insulates the water from
the lead, but some areas of the country have very soft water, with little or
no calcium content, so I'm not sure that this argument " holds water " (
ouch !! ).

Even if lead is soluble in water, I can't imagine that it is extremely so,
and I would have thought that water treatment plants would have removed any
in their raw input, or could be made to do so fairly easily. Of much more
concern, I would have thought, must be the organic fertilizers and such that
get into the water supply. I don't know what the situation is your side of
the pond ( I'm assuming you are US based ) regarding landfill. All we ever
hear over here, is that your glorious leader is not a very eco-friendly guy,
but I'm sure from what I've seen on my frequent visits, that isn't the case
amongst the general population.

To Franc. I'm not sure what the percentage of lead is in the lead-glass that
is used for CRT faceplates, but as far as I am aware, it's another
technology that has been deemed not to have a viable alternative, so has
been granted an exemption from the RoHS directive. Total recycling of this
glass should be possible, with no lead-to-environment contamination. As well
as the faceplate glass, I seem to recall that there is some issue also, with
getting a vacuum-proof seal between the CRT pins and the glass, that
involves possibly some other hazardous substance covered by the directive.
Interesting stuff. If anyone has any strong objections on the grounds of
this being off-topic, say so, and I'll stop raising new points ...

Arfa
 
A

Arfa Daily

Jan 1, 1970
0
ian field said:
Some good points there, I didn't know lead was no longer used for 12bore
shot - any idea what they use instead?

Regardless of the WEEE directive, lead was originally mined out of the
ground and one way or another it will eventually end up back there, also I
had always held the opinion that the common solder alloys were
substantially less toxic than lead on its own, if this is true then the
manufacture of lead/tin solder actually reduces the availability of lead
wherever it ends up at end of life.
Click to expand...


I have a friend who owns a clay range. A few years back, there was a big
thing locally about shot from his range ending up in a wheat field behind.
This also lead to complaints on the noise issue. As far as I recall, they
changed over to a different cartridge, that has a non-lead shot content, and
a lower velocity powder charge, which cuts down on the noise, making more of
a soft whumph noise than the previous sharp bangs. I haven't seen him for a
while, nor been to the range, so I don't know what the effects of this have
been on the sport, but I will try to find out, if you like.

I think that the issue with ' out of the ground / back to the ground '
that's usually quoted, is that it came out of the ground as a naturally
occuring ore, but goes back as refined lead. But I'm still not convinced
that this whole thing is not just an eco smokescreen, keeping beaurocrats in
a job. I'm sure that there are much more hazardous substances getting into
the eco system, than lead from solder.

Arfa

Arfa
 
J

Jim Yanik

Jan 1, 1970
0
First to Jim two posts above. You are missing the point. The
electronic waste will no longer sit in landfill, because the new WEEE
directive, in Europe at least, will make sure that the equipment is
recycled, and any lead content removed. Electronic equipment in
landfill will soon become a thing of the past. Anyway, just how
soluble is lead in water ? I'm not too sure, but I expect some clever
chemistry graduate will tell us. In the past, water was delivered to
all households in the UK via lead pipes. In a lot of older properties,
it still is. Certainly, the house that I grew up in had lead pipework.
I am not aware of people of my generation all dying of lead poisoning,
or having suffered intelligence lowering due to lead-induced brain
damage. In fact, since lead piping has been being removed here, the
kids have been getting progressively thicker ... !! I have heard
people say that delivering water via lead pipes is of no consequence,
because the pipes quickly get an internal coating of limescale, that
insulates the water from the lead, but some areas of the country have
very soft water, with little or no calcium content, so I'm not sure
that this argument " holds water " ( ouch !! ).

Even if lead is soluble in water, I can't imagine that it is extremely
so, and I would have thought that water treatment plants would have
removed any in their raw input, or could be made to do so fairly
easily. Of much more concern, I would have thought, must be the
organic fertilizers and such that get into the water supply. I don't
know what the situation is your side of the pond ( I'm assuming you
are US based ) regarding landfill. All we ever hear over here, is that
your glorious leader is not a very eco-friendly guy, but I'm sure from
what I've seen on my frequent visits, that isn't the case amongst the
general population.

To Franc. I'm not sure what the percentage of lead is in the
lead-glass that is used for CRT faceplates, but as far as I am aware,
it's another technology that has been deemed not to have a viable
alternative, so has been granted an exemption from the RoHS directive.
Total recycling of this glass should be possible, with no
lead-to-environment contamination. As well as the faceplate glass, I
seem to recall that there is some issue also, with getting a
vacuum-proof seal between the CRT pins and the glass, that involves
possibly some other hazardous substance covered by the directive.
Interesting stuff. If anyone has any strong objections on the grounds
of this being off-topic, say so, and I'll stop raising new points ...

Arfa
Click to expand...

I believe the lead in CRT glass does not leach out.
It's probably the monitor electronics is where the lead is coming from.
Also,it's not just the faceplate the lead-glass is used,as the lead is
intended to attenuate X-rays which I believe scatter BACK from the target.
 
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