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lead free solder

C

Cydrome Leader

Jan 1, 1970
0
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?
 
F

Fred McKenzie

Jan 1, 1970
0
Cydrome Leader said:
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
 
C

Cydrome Leader

Jan 1, 1970
0
Arfa Daily said:
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

Luckily, here in the US you can buy and use any type of solder ever made.
The issue which I've avoided but can't be ignored is that there's lots of
that RoHS crap floating around and I will at some point have to deal with
it.

A friend that's starting out in electronics and building some basic kits
wants to use a soldering iron.

I'm not clear on if I should just grab a spare and hand them a roll of
60/40, or get new tips for them and let them start "fresh" with some
lead-free sample packs from trade shows. It's all through the hole stuff,
and probably doesn't matter at al for what they're doing now.

Also are there any foolproof method of telling if lower production type
items are traditional or lead-free?
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

Boo
 
S

Smitty Two

Jan 1, 1970
0
Fred McKenzie said:
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?
 
J

Jeffrey D Angus

Jan 1, 1970
0
Smitty said:
Huh? What the devil are you talking about?

This is not new. Tektronix used to include a bit of silver bearing
solder with their scopes so you wouldn't ruin the plated ceramic
terminal strips if you changed out parts.

Jeff
 
C

Cydrome Leader

Jan 1, 1970
0
Arfa Daily said:
If the friend is not already an experienced hand-solderer, and there is no
legal requirement for him to use lead-free, then I would not start him off
with it. Even the latest alloys specifically for hand soldering, still have
a bit of a 'pasty' feel to them, and are not intuitive to solder with, as
leaded solder was. Even for the most experienced of us, lead-free solder is
still quite easy to make bad (or mechanically not very good) joints with,
particularly on large components, and those which are reluctant to take
solder in the first place.

If your friend is doing kit building just for himself, then maybe you could
consider introducing lead-free at some point in his training, once he has
got the hang of leaded soldering, but if there is any commercial angle to
his activities, where any lack of reliability will come down on his head,
then I would say stick to leaded if your local laws allow. Of course, if
there is a commercial angle, and he has any intention of selling
internationally, then he must consider that it may be a requirement that he
uses lead-free.

I guess I have another question based off what you're saying.

Aside from silver plated or specialty parts in an old scope, is there any harm done
in using real solder in a RoHS device?

Here's an example.

a resistor mounted through-hole has a bad joint. Normal repair just reheat the joint
and add more solder. No problem.

Say it's Rohs assembly this time around. Will regular 60/40 even melt and fuse with
the lead free stuff, or you do you need to remove the tin stuff and then resolder
from scratch, or is it really just best to resolder with lead free solder?

I've not tested it, because I really don't want to botch up my tips, sponges all
that stuff.
There doesn't seem to be a reliable way of telling lead-free for definite,
without some 'help' from the manufacturers. This help is usually in the form
of a symbol silkscreened on the board that is either a circle with the
letters Pb in it, and a strike-through line across it, or the letters "PbF".
In general, if a commercially sold piece of consumer electronics has been
built in either Europe or the far east since mid 2006, it will definitely be
lead-free. I believe Australia is the same, but I'm not sure of the date
they went lead-free. Perhaps one of the Oz lads in the group can help out
with that one. Mr N.Cook on here has done considerable research on trying to
come up with a definitive test for lead-free. If you search this group for
the last 6 months of posts by him, you should catch them all. Other than
this, with a good eye, you can identify most lead-free constructed boards.
The joints tend to have a dull grey surface, and are shaped more like a
volcano than the typical leaded joint which has a concave profile between
the pad and component leg. If you apply a normal non temperature controlled
iron to a lead-free joint, you will quickly spot the difference. It just
doesn't melt, flow and resolidify in the same eutectic way as leaded
solder - particularly at leaded solder temperatures.

Interesting. I may need to tear apart some equipment I have and compare. It's
alleged the the new version is rohs while the last one are conventional.
 
S

Smitty Two

Jan 1, 1970
0
Jeffrey D Angus said:
This is not new. Tektronix used to include a bit of silver bearing
solder with their scopes so you wouldn't ruin the plated ceramic
terminal strips if you changed out parts.

Jeff

So adding tin/lead solder to a silver component terminal turns the
connection into what, a non-conductive roofing shingle or something? I'm
pretty sure I would have heard from a customer or two if the thousands
of RoHS components I've soldered with 63/37 weren't conducting
electricity.
 
C

Cydrome Leader

Jan 1, 1970
0
WangoTango said:
I've reworked a thousand "RoHS" boards with good 'ol 60/40 and have
never had a failure of one of MY joints, or any problems related to
them. The stupid part of all of this is, just how are you going to know
EXACTLY which lead free solder was used to begin with? There a a lot of
formulations, from good 'ol SAC (Tin, silver, copper) to a bunch of
alloys with all kinds of weird stuff in them. So, if you grab a spool
of SAC and the OEM used a bismuth or zinc alloy, what is going to
happen? I just clean up as much of the original solder as possible with
solder wick and put down 60/40 and forget about it. I might also add,
that we have mixed RoHS and non-RoHS parts for years with no failures
due to the tin/lead solder. In fact UPS has destroyed more boards by
running them over than any other failure mechanism.

Well this sounds like good news. Thanks for pointing out the solder wick.
I don't generally use the stuff, but it's does a good job of removing as
much old solder as possible.
 
S

Smitty Two

Jan 1, 1970
0
Cydrome Leader said:
a resistor mounted through-hole has a bad joint. Normal repair just reheat
the joint
and add more solder. No problem.

99% of the time, there's plenty of solder already there. So add FLUX and
reheat the joint. Same procedure for lead-free, of course.
 
N

N_Cook

Jan 1, 1970
0
Arfa Daily said:
In general, based on practical experience, I think I would agree with you. I
have also reworked joints on boards that were built with lead-free, but not
subject to the European regs, with regular 60/40 lead solder, and I have
never knowingly had a problem - at least short term. But who's to say what
the long-term effects may be? I mentioned in my original reply about the
'metalurgical wisdom' in this regard. I got this direct from conversations
with a Dr Paul somebody-or-other who is an expert in the field and head of
the subject for a UK consultancy firm, when I was researching for an article
that I was writing on the subject, for a UK trade magazine. He had produced
a paper which was available on the 'net, and he was quite adamant that the
two solder types should not be mixed in the same joint, because of long term
degradation of the integrity of the joint. I've no idea whether this belief
was theoretical or based on experimentation, as I did not ask the question.
That sort of depth was beyond the scope of the article.

On balance, I still feel that the right *overall* practice, is to rework
joints with the same basic formulation as they were made with. Obviously,
it's not going to be a major problem if a reworked joint in a TV set or
whatever, fails down the line because of it having been reworked with the
wrong solder type, but I would hate to think that some item that I had
repaired finished up in a critical application, and later failed because of
me. Remember also, that most of us outside of the USA are in a slightly
different position from you folks in that we must not, officially under
threat of law, do anything to compromise the RoHS certification of a
product. That includes using non RoHS compliant replacement parts, and
solder to fix them in with ... :-\

Arfa


It is not possible to do "long term" experiments , you have to do
accelerated aging and hope it is comparable. Now one way to accelereate
aging effects of solder integrity is to subject boards to vibration and
cycles of heating and cooling, er come to think of it ......
 
S

Smitty Two

Jan 1, 1970
0
Arfa Daily said:
Remember also, that most of us outside of the USA are in a slightly
different position from you folks in that we must not, officially under
threat of law, do anything to compromise the RoHS certification of a
product. That includes using non RoHS compliant replacement parts, and
solder to fix them in with ...

I'm just curious, how would this "threat of law" scenario play out?
Assume some authority finds out that you've got a roll of 63/37 stashed
under the floorboards, (or a bin of old leaded components) and you pull
it out on occasion for an illegal repair. Would the cops come? Throw you
in the slammer? Would you be facing jail time, a fine, revocation of
your business license?

I'm reminded of my business neighbor a number of years back, who had a
600 watt amplifier on his CB radio. (Legally, CBs are limited to 4
watts, IIRC) I called the FCC, gave him his name and address. They said,
"Sorry, we don't enforce that law. It's too costly."

I'm guessing you're in an analogous situation, and that short of hanging
a giant neon sign over your shop that says "**** RoHS, we still use
lead," you'd never be bothered. But, my guesses are often wrong ...
 
A

Adrian Tuddenham

Jan 1, 1970
0
Smitty Two said:
I'm just curious, how would this "threat of law" scenario play out?
Assume some authority finds out that you've got a roll of 63/37 stashed
under the floorboards, (or a bin of old leaded components) and you pull
it out on occasion for an illegal repair. Would the cops come? Throw you
in the slammer? Would you be facing jail time, a fine, revocation of
your business license?

The usual procedure with laws like this is to find one small operator
who has made a mistake and smash him to pieces with the maximum of
publicity. It is supposed to frighten the others and is a lot cheaper
than chasing them as individuals.

It would have been a lot better if the manufacturers in other countries
had got together and told the EU that they were going to continue to use
lead in their solder. If Europe didn't like it, they could do without
the products. (Did I hear somewhere that this was exactly what the Swiss
watchmaking industry did - or did I imagine it?)
 
B

Baron

Jan 1, 1970
0
Smitty Two Inscribed thus:
I'm just curious, how would this "threat of law" scenario play out?
Assume some authority finds out that you've got a roll of 63/37
stashed under the floorboards, (or a bin of old leaded components) and
you pull it out on occasion for an illegal repair. Would the cops
come? Throw you in the slammer? Would you be facing jail time, a fine,
revocation of your business license?

I'm reminded of my business neighbor a number of years back, who had a
600 watt amplifier on his CB radio. (Legally, CBs are limited to 4
watts, IIRC) I called the FCC, gave him his name and address. They
said, "Sorry, we don't enforce that law. It's too costly."

I'm guessing you're in an analogous situation, and that short of
hanging a giant neon sign over your shop that says "**** RoHS, we
still use lead," you'd never be bothered.

Thats about the size of it ! ;-)
 
S

Smitty Two

Jan 1, 1970
0
See
http://www.metricmartyrs.co.uk/Home/TributetoStevenThoburn/tabid/64/Default.as
px

picked at random from many hundreds of web entries.

So, Smitty, that's what's meant theoretically - and sometimes in reality -
by "under threat of law", and I sure as hell am not going to put myself in
the EU firing line by anything that I do professionally. I have no desire to
become the first 'Solder Martyr' ... :-|

Arfa

Wow, that is an awful story. Anyone working on the movie yet?
 
C

Cydrome Leader

Jan 1, 1970
0
Baron said:
Smitty Two Inscribed thus:


Thats about the size of it ! ;-)

haha. make sure that neon sign has leaded glass, is pumped full of mercury
and uses a non GFCI transformer with a really low power factor.
 
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