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From: Cydrome Leader on 24 May 2010 17:36
What happens if you use regular solder on something that was originally lead-free,
or you get the lead free solder on a regular iron?

I understand manufacturers keep separate lines as mixing the two is bad, but what
about in the repair world?

Does lead free solder mess up good quality tips or anything like that?
From: Fred McKenzie on 24 May 2010 20:29
In article <htergh$8hi$3(a)reader1.panix.com>,
Cydrome Leader <presence(a)MUNGEpanix.com> wrote:

> What happens if you use regular solder on something that was originally
> lead-free,
> or you get the lead free solder on a regular iron?
>
> I understand manufacturers keep separate lines as mixing the two is bad, but
> what
> about in the repair world?
>
> Does lead free solder mess up good quality tips or anything like that?

CL-

One problem occurs if you use leaded solder on surface-mounted
components. Lead amalgamates with the silver that is "fired" onto these
components, ruining their electrical connection.

I've read that a lead-contaminated solder iron can cause the problem
even if lead-free solder is used. I've never heard of the opposite case
with lead-free solder.

To be safe, I keep two sets of equipment.

Fred
From: Arfa Daily on 24 May 2010 20:58

"Cydrome Leader" <presence(a)MUNGEpanix.com> wrote in message
news:htergh$8hi$3(a)reader1.panix.com...
> What happens if you use regular solder on something that was originally
> lead-free,
> or you get the lead free solder on a regular iron?
>
> I understand manufacturers keep separate lines as mixing the two is bad,
> but what
> about in the repair world?
>
> Does lead free solder mess up good quality tips or anything like that?

The metalurgical wisdom is that leaded and lead-free solders should not be
mixed in the same joint, as the mixing can, apparently, compromise the
long-term integrity of the joint. I don't know whereabouts in the world you
are, but across Europe, strictly speaking, it is actually illegal to use
leaded solder, or non RoHS components, to repair anything manufactured in
lead-free after implementation of the RoHS directive, which was June 2006 (I
think) in the UK. Prior to that time, some manufacturers, notably Sony, were
already manufacturing in lead-free, and insisting that their dealers used
*only* lead-free to effect repairs to all of their equipment, irrespective
of whether it was originally manufactured in lead-free or leaded solder.
This actually flew in the face of expert advice which recommended using only
the type of solder that the equipment was originally manufactured with.
There was no legal mandate to use lead-free solder for repairs to any
equipment manufactured prior to RoHS implementation, whether it was
manufactured with lead-free, or not. There is still no legal requirement to
use lead-free solder to repair any equipment originally built with leaded
solder.

As to whether lead-free damages tips, that's a bit of a grey one. If you are
using iron-clad tips, then yes, it does rot them much quicker than leaded
solder does. The reasons for this appear to be threefold. According to
Cooper Tools, who manufacture Weller soldering equipment, the composition of
lead-free solder has a tendency to 'leach' iron from the tip coating,
resulting in it failing quite quickly, and exposing the underlying copper,
which then rapidly burns away. Secondly, because lead-free solder does not
wet joints as well as leaded solder did, much more aggressive fluxes have to
be used, and again, these have a detrimental corrosive effect on the iron
tip coating. Thirdly, the temperatures required for lead-free hand soldering
are typically 30 deg C higher than those required by leaded solder. These
higher tip temperatures tend to exacerbate tip degradation. My experience
with Weller iron clad tips, would tend to bear out the contention that
lead-free solder destroys them much quicker than leaded did.

That said, a few months back, Antex changed their tips back to being what
looks like chrome plated, as they used to be 30 years back. This seems to
have produced a significant improvement in the life of their tips, and I
wonder if they have done it to combat the negative effects on tip life that
lead-free has given us.

As to mixing leaded and lead-free on the same tip, unless you are going to
keep completely separate irons burning all the time, I think that it's
pretty much unavoidable in a typical workshop environment, dealing with many
types and ages of equipment. If you keep a wet sponge on your iron's stand,
and get into the habit of giving the tip a wipe every time you pick the iron
up, then I don't think that any residual quantities of either type left on
the tip, will be enough to cause any problems.

Arfa


From: Smitty Two on 25 May 2010 02:45
In article <fmmck-B55AAB.20291624052010(a)5ad64b5e.bb.sky.com>,
Fred McKenzie <fmmck(a)aol.com> wrote:

> One problem occurs if you use leaded solder on surface-mounted
> components. Lead amalgamates with the silver that is "fired" onto these
> components, ruining their electrical connection.

Huh? What the devil are you talking about?
From: stickyfox on 25 May 2010 11:09
On May 24, 5:36 pm, Cydrome Leader <prese...(a)MUNGEpanix.com> wrote:
> What happens if you use regular solder on something that was originally lead-free,
> or you get the lead free solder on a regular iron?
>
> I understand manufacturers keep separate lines as mixing the two is bad, but what
> about in the repair world?
>
> Does lead free solder mess up good quality tips or anything like that?

Unless you have an in with the manufacturer, or you exclusively repair
top-tier industrial hardware that is very well documented, you have no
idea what kind of solder was originally used. Yes, it may have a green
checkmark on it, and yes, you may be very competent at identifying
lead-free solder by the look and feel, but there is a wide variety of
lead and lead-free solders out there, and mixing two lead-free alloys
can make a connection that's as unreliable as a mixed lead/lead-free
joint. Essentially you are randomly mixing metals with no controls.
You also don't know if the engineers chose to use non-lead-free
components on a lead-free board, or tweaked the profile to compensate
for the "right" solder being unavailable. If you're fixing something
made in China, you can't claim to know anything at all about it. That
board could have been assembled with melted-down jewelry from Wal-
Mart. So much goes on behind the scene that you'll always be
guessing.

I have never heard of lead and silver causing trouble. I've been using
RS 2% Ag "hi tech" solder since the 80s for no particular reason other
than the old tektronix scopes I worked on back then had silver-ceramic
barrier strips in them; you had to use solder with silver or it would
strip the metal from the ceramic. The stuff works just as well on
motherboard bridges today.

Another thought on mixing lead and lead-free: While it may cause
unreliability issues, you'll never have a warranty claim as a result.
We're talking decades here, not months. How long is that piece of
equipment going to be in use?
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