60/40 vs. 63/37 Solder

[Joe]

Why are there these two very similar solders? Is there any situation
where one is better than the other?

I understand the eutectic nature of 63/37, and I wonder if/when 60/40
might ever be better to use.

--- Joe

 

[John Doe]

none given.now (Joe) wrote:

Why are there these two very similar solders? Is there any
situation where one is better than the other?

Dunno, but... If you do detail work, try water-soluble flux
solder. You just wipe off the residue for a sparkling clean
circuit.

Good luck and have fun.

 

[Smitty Two]

In article <4c3ec127$0$4762$c3e8da3@news.astraweb.com>,
John Doe <jdoe@usenetlove.invalid> wrote:

none given.now (Joe) wrote:

Why are there these two very similar solders? Is there any
situation where one is better than the other?

Dunno, but... If you do detail work, try water-soluble flux
solder. You just wipe off the residue for a sparkling clean
circuit.

Good luck and have fun.

60/40 was the standard for many years, until it was learned that 63/37
was more accurately eutectic. 60/40 was kept around as a legacy product
since millions of customers worldwide had written the spec into their
procedural documentation. But distributors (in my part of the world
anyway) stopped stocking much of a 60/40 selection about 20 years ago.

As for water soluble flux, it has at least one significant drawback; it
is corrosive at room temperature (unlike RMA for example which is only
"active" when heated.) Therefore, any flux residue left on the board (or
whatever you're soldering) will lead to corrosion. Without full
immersion in a sonic tank, it can be difficult or impossible to wash it
all away.

 

[PeterD]

On Thu, 15 Jul 2010 00:54:43 -0700, none@given.now (Joe) wrote:

Why are there these two very similar solders? Is there any situation
where one is better than the other?

I understand the eutectic nature of 63/37, and I wonder if/when 60/40
might ever be better to use.

--- Joe

The advantage is when you need a lower melting temperature. However,
the difference is slight. 63/37 also does not have as much of a
plastic state when melting.

 

[William Sommerwerck]

As far as I know, no.

63/37 has been "known" to be eutectic for at least 50 years. (I read about
it in "Popular Electronics" as a wee babe.)

The only reason 60/40 was ever manufactured in the first place is that tin
is more expensive than lead, so 63/37 solder costs more. Unless you're
Really Cheap, 63/37 is always preferable. It has slightly greater mechanical
strength, too, though this is rarely a consideration.

J Gordon Holt, who founded "The Stereophile", had his own theories about
soldering. Back in the days when people assembled vacuum-tube equipment from
kits, he recommended simply poking component leads through the lugs, and
soldering them without crimping them. His reasoning was that, if the
component ever needed replacement, you wouldn't have to fiddle with
uncrimping it. (If you've ever unsoldered old equipment, you know what a
tsuris this can be.) The "catch", of course, is that both the lug and the
lead have to be very clean, and you're more likely to get a cold or
incomplete connection. This is a situation where you would /definitely/ want
to use 63/37.

While I'm on the subject... I once asked the late Bob Tucker, * who wrote
the user manuals for Dynaco, why the soldering instructions were, at one
point, obviously in the "wrong" sequence. He explained that Dynaco's
"policy" was that, once a lug had three wires in it, it was to be soldered.
There was otherwise too-great a chance of it being overlooked and remaining
unsoldered, only to cause problems down the line.

* Bob, who passed on in the late '80s, was one of the nicest, most-gracious
people you could ever hope to meet. He was, perhaps surprisingly, also one
of the handsomest men I've ever seen -- by comparison, most actors and
fashion models are plain -- but he didn't seem aware of it.

 

[Boris Mohar]

On 15 Jul 2010 08:04:55 GMT, John Doe <jdoe@usenetlove.invalid> wrote:

none given.now (Joe) wrote:

Why are there these two very similar solders? Is there any
situation where one is better than the other?

Dunno, but... If you do detail work, try water-soluble flux
solder. You just wipe off the residue for a sparkling clean
circuit.

Good luck and have fun.

Water soluble flux is conductive. You should wash it off not just wipe it.

--
Boris

 

[John Larkin]

On 15 Jul 2010 08:04:55 GMT, John Doe <jdoe@usenetlove.invalid> wrote:

none given.now (Joe) wrote:

Why are there these two very similar solders? Is there any
situation where one is better than the other?

Dunno, but... If you do detail work, try water-soluble flux
solder. You just wipe off the residue for a sparkling clean
circuit.

And one that makes a great humidity sensor.

John

 

[Smitty Two]

In article <i1mtb8$8u4$1@news.eternal-september.org>,
"William Sommerwerck" <grizzledgeezer@comcast.net> wrote:

The only reason 60/40 was ever manufactured in the first place is that tin
is more expensive than lead, so 63/37 solder costs more.

Cite, please? (and I don't mean a link to commodity prices)

 

[Robbie Hatley]

"Joe" wrote:

I wonder if ... 60/40 might ever be better to use.

No.

For hand soldering, I recommend Sn63Pb37 wire solder with an activated
rosin flux core. Use thin solder, about 23AWG; it melts the faster, for less
chance of cold joints. For surface mount, use even thinner, about 28AWG.

Avoid organic or water-soluable flux unless you're going to wash the board
thoroughly after soldering.

Rosin flux can be removed with 99pct isopropyl alcohol ($1 a bottle at your
corner drug store). But frankly, I recommend NOT removing the rosin flux
scum. Leave it on; it's inert, airproof, waterproof, sweatproof, so it protects
the joint.

--
Been soldering stuff since 1973,
Robbie Hatley
lonewolf [[at]] well [[dot]] com

 

[William Sommerwerck]

The only reason 60/40 was ever manufactured in the first place is
that tin is more expensive than lead, so 63/37 solder costs more.

Cite, please? (and I don't mean a link to commodity prices)

I can only cite "common sense". 63/37 has always been more-expensive than
60/40.

 

[GregS]

In article <7a307a68-f754-413e-8113-4b9d0ce7a236@c10g2000yqi.googlegroups.com>, George Herold <ggherold@gmail.com> wrote:

On Jul 15, 11:42=A0am, John Larkin
jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
On 15 Jul 2010 08:04:55 GMT, John Doe <j...@usenetlove.invalid> wrote:

none given.now (Joe) wrote:

Why are there these two very similar solders? =A0Is there any
situation where one is better than the other? =A0

Dunno, but... If you do detail work, try water-soluble flux
solder. You just wipe off the residue for a sparkling clean
circuit.

And one that makes a great humidity sensor.

John


Yeah, My prototype of a board with several high meg resistors (up to 1
gig.) was put together by myself with old Kester "44" (rosin flux.)
Worked great. Production did a few with their favorite water based
flux... No good! Now I have to convince them to go back to the old
standard. The new ROHS fluxes seem to be even worse. I measured a
few meg ohms between pads that had been 'cleaned'.... NOT.

I had a lot of problems with high Z circuitry. Got under the pads.
Some boards I had to clean/dry 10 times. In the interim, some of the cleaner
I used got into some caps and started their own circuit mess.

greg

 

[David Eather]

On 15/07/2010 5:54 PM, Joe wrote:

Why are there these two very similar solders? Is there any situation
where one is better than the other?

I understand the eutectic nature of 63/37, and I wonder if/when 60/40
might ever be better to use.

--- Joe

PeterD mentioned the significant parameter in his post. because it is a
eutectic mixture 63/37 does not have "much of a plastic state" this
means it is more sensitive to movement in the joint while the solder is
cooling - if the connections are unstable it forms more dry joints. This
was important with point to point wiring but is now less important with
PCBs.

You can normally use either solder for any job but the "old timers"
experience would suggest 60/40 is the better choice for wiring front
panels, flying leads and the like and 63/37 would be better for heat
sensitive components.

(for the obnoxious who will claim there is no difference - please note
that those doing the jobs *did* find a difference and thought it
significant enough to bother about)

 

[Dave Platt]

Why are there these two very similar solders? Is there any situation
where one is better than the other?

I understand the eutectic nature of 63/37, and I wonder if/when 60/40
might ever be better to use.

My understanding is that 60/40 has somewhat better wetting properties
than 63/37, at least with some contact materials. Some people prefer
it for that reason.

63/37 makes a sharp transition between liquid state and solid state at
a single, well-defined temperature. 60/40 goes through a transition
between these two states over a significant range of temperature - in
between the fully-solid and fully-liquid states it can have a somewhat
mushy texture. Some people feel that 60/40 brings with it a somewhat
higher risk of creating a "cold" solder joint (inadequate fusion with
the contact surfaces) if the joint is moved or stress while the solder
is dropping through its mushy-state temperature region.

--
Dave Platt <dplatt@radagast.org> AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

 

[William Sommerwerck]

Because it is a eutectic mixture, 63/37 does not have "much
of a plastic state". This means it is more [sic] sensitive to
movement in the joint while the solder is cooling -- if the
connections are unstable it forms more [sic] dry joints.

I don't what you meant to say, but what you did say is backwards. Eutectic
solder is less likely to produce a dry or crystallized joint.

 

[George Herold]

On Jul 15, 11:42 am, John Larkin
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:

On 15 Jul 2010 08:04:55 GMT, John Doe <j...@usenetlove.invalid> wrote:

none given.now (Joe) wrote:

Why are there these two very similar solders?  Is there any
situation where one is better than the other?  

Dunno, but... If you do detail work, try water-soluble flux
solder. You just wipe off the residue for a sparkling clean
circuit.

And one that makes a great humidity sensor.

John

Yeah, My prototype of a board with several high meg resistors (up to 1
gig.) was put together by myself with old Kester "44" (rosin flux.)
Worked great. Production did a few with their favorite water based
flux... No good! Now I have to convince them to go back to the old
standard. The new ROHS fluxes seem to be even worse. I measured a
few meg ohms between pads that had been 'cleaned'.... NOT.

George H.

 

[Jim Yanik]

"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in
news:i1nqh7$7qt$1@news.eternal-september.org:

Because it is a eutectic mixture, 63/37 does not have "much
of a plastic state". This means it is more [sic] sensitive to
movement in the joint while the solder is cooling -- if the
connections are unstable it forms more [sic] dry joints.

I don't what you meant to say, but what you did say is backwards.
Eutectic solder is less likely to produce a dry or crystallized joint.

I agree;
the eutectic joint solidifies faster and thus less likely to move while the
solder is still "plastic".


--
Jim Yanik
jyanik
at
localnet
dot com

 

[Smitty Two]

In article <i1nhau$vj6$1@news.eternal-september.org>,
"William Sommerwerck" <grizzledgeezer@comcast.net> wrote:

The only reason 60/40 was ever manufactured in the first place is
that tin is more expensive than lead, so 63/37 solder costs more.

Cite, please? (and I don't mean a link to commodity prices)

I can only cite "common sense". 63/37 has always been more-expensive than
60/40.

Then you can't substantiate your contention that 60/40 was THE worldwide
standard for tens of years just because it was a few pennies cheaper per
pound? That is the statement of yours with which I take issue.

 

[William Sommerwerck]

The only reason 60/40 was ever manufactured in the first place is
that tin is more expensive than lead, so 63/37 solder costs more.

Cite, please? (and I don't mean a link to commodity prices)

I can only cite "common sense". 63/37 has always been
more-expensive than 60/40.

Then you can't substantiate your contention that 60/40 was THE
worldwide standard for tens of years just because it was a few pennies
cheaper per pound? That is the statement of yours with which I take issue.

I have no objection to your objection.

However, 60/40 was never, ever, "a few pennies per pound" cheaper than
63/37. For the last 30 years, the price of eutectic solder has been
sufficiently higher to make one think twice before buying it. The last time
I purchased solder, I decided that a one-pound roll of Kester 44 would last
the rest of my life, and I splurged. (At this point in my life, my
prediction is coming true. I rarely solder any more. If I drop dead, someone
digging through the junk will find a pleasant surprise. Assuming they know
what 63/37 is.)

I just checked Parts Express, and a 1# roll of Kester 44 60/40 is $22.23.
63/37 is $26.85. That's a $4.62 difference, almost 21% more -- hardly
"pennies per pound". When I bought the same product some years back, my
memory is that the price was around $7.50 for the 60/40, $9 for the 63/37.
Even that wasn't "pennies per pound".

I looked at the MCM site for Ersin products. Get this... MCM describes its
house brand of 60/40 solder as "provid[ing] the lowest possible melting
point".

Businesses almost always try to cut every corner they can. If you think your
solderers -- or soldering machines -- are doing a good job, you might prefer
to buy the less-expensive 60/40.

When I worked at Bendix Field Engineering, I often walked through the
section where a bunch of women (never men) soldered assemblies, following
NASA standards. I never thought to ask whether they used 60/40 or 63/37.

 

[Dave Plowman (News)]

In article <KJydndUeloVE2KLRRVn_vwA@giganews.com>,
Robbie Hatley <see.my.sig@for.my.contact.info> wrote:

Rosin flux can be removed with 99pct isopropyl alcohol ($1 a bottle at
your corner drug store). But frankly, I recommend NOT removing the
rosin flux scum. Leave it on; it's inert, airproof, waterproof,
sweatproof, so it protects the joint.

Strange to see this in print, as everyone seems to spend ages removing
flux. I don't and have never had a problem.

--
*The only difference between a rut and a grave is the depth.

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

 

[William Sommerwerck]

Rosin flux can be removed with 99% isopropyl alcohol
($1 a bottle at your corner drug store).

You won't find 99% for $1. (91%, maybe.)