Weller WTCPT tip not hot enough

[Eeyore]

Arfa Daily wrote:

snip

Whilst you are correct in that a 700 deg tip melts lead-free solder, it does
not do so anything like as well as it does with leaded solder. Although
lead-free solder does not have as nice a melt / flow characteristic as
leaded in the first place, this undesirable quality is made much worse by
not having enough temperature on it - particularly when soldering a
component with a high thermal inertia, such as a connector or power
semiconductor.

Absolutely spot on !

Graham

 

[Eeyore]

Arfa Daily wrote:

"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message
Arfa Daily wrote:

Just to be clear though, only mandated for items placed on the market
after June 2006, and which don't have a waiver. Items manufactured prior to

that using conventional leaded solder, can continue to be repaired /
reworked
/ modified with leaded solder and non RoHS compliant components. New items
for non commercial i.e. amateur use, can still be constructed in whatever
component and solder technology you like.

Absolutely, although we have no idea what he's soldering. I still prefer
800F tips for quick neat soldering.


I still use 700s because of the problem of 800s burning out quicker when
left idling all day,

Well I simply don't let it idle all day. It's guarenteed to give those nasty
'inter-metallic oxides' in the long term anyway that make re-tinning near
impossible. A guy I used to work with would switch on the bench (including iron)
and maybe not use the iron all day. Whenever I noticed, I'd switch it off again.
Why waste electricity anyway ?

Graham

 

[Eeyore]

Jim Yanik wrote:

"Arfa Daily" wrote
"Eeyore" wrote
Arfa Daily wrote:

I still use 700s because of the problem of 800s burning out quicker
when left idling all day,

I don't let that happen and re-tin and wipe the tip regularly. I
probably 'waste' as much solder as I use !

Plus Farnell IIRC sells some aggressive (iron) oxide remover that can
help restore a 'damaged' tip. It comes in a little circular tin.

I have some, and jolly good it is too, although I wonder just how much
that's eating away at the tip, as well ...

Did you never ever use ancient pure copper tips ? That's why Multicore added
a small percentage of copper to some of their solders.

IIRC,that has some powdered solder mixed in with the flux.
It cleans AND tins.

That's the stuff.

(of course,AFAIK,it's not lead-free....)

Damn good news !

Graham

 

[Eeyore]

William Sommerwerck wrote:

Good soldering technique will not give cold solder joints,
regardless of the tip temp. High tip temp is probably
a poor way to overcome poor technique.

I would absolutely dispute that statement.

As would I. The temperature has to be at least high enough to bring the
solder to its "liquidus" state. (Which is one of the reasons eutectic solder
is preferable.)

Using a higher temp iron will certainly pump more heat into the
joint in a given time, but it also results in more temp difference
across the joint, so you may be more likely to get what looks
like a good joint on the heated side, but with little penetration.

This is bilge.

Quite. The total stress on the components is in fact likely to be be LESS.

Graham

 

[Eeyore]

Jim Adney wrote:

700 F is still quite a bit above the liquidus.

And how long do you think it's actually going to take the SOLDER to reach that temp ?

Ever heard of thermal inertia ?

Graham

 

[Eeyore]

Rich Webb wrote:

On Tue, 26 Aug 2008 10:56:32 +0100, "Arfa Daily"
arfa.daily@ntlworld.com> wrote:
[snip...snip...]
There are some interesting notes here about why the 'standard' tips burn out
quickly, when used with lead-free

http://www.cooperhandtools.com/europe/sales_literature/documents/Leadfree_Info_GB.pdf

Interesting phrase there: "Clean the tip on a watery swamp." That one
required a quick mental recalibration...

On that issue, though, what are your thoughts on the use of brass
turnings as a tip cleaner vice a dunk in the swamp? I switched over to
the bowl of brass a while ago and now prefer it to the damp sponge.

I tried one of those brass things and it was useless IMHO. It left loads of crap on the
tip. Use a moist Weller sponge every time.

Graham

 

[Eeyore]

GMAN wrote:

"nobody >" wrote:

I'll have to look up what Pace is doing for RoHs soldering and
desoldering tips.

At least I know my own home WTCPT unit will cope with RoHs solder in a
fashion.

This EU RoHs requirement for lead free solder is the precise reason the XBOX
360 has had such a high failure rate.

I hate to think what's lurking in the woodwork. At least aerospace is exempt !

I don't know about car ECUs though. That could be fun. Lead-free hates vibration with a vengeance.

As I may have said elsewhere I know that at least one loudspeaker manufacturer got an exemption because the
sound was causing lead-free lead-out wire terminations to fail. There's implications there for a lot of
sound equipment.

Graham

 

[Eeyore]

Bob Shuman wrote:

Having worked in electronics assembly and manufacturing for many years, I
can confirm your assumption that all new production work gets wave soldered
and it has its own set of issues as evidenced by many cold solder joints
found in the field! That said, hand irons are still used for repairs...

I recall our Bombay sub-contract had a decent wave solder machine with proper
pre-heat etc, good meterials used like Kester solders and fluxes etc. Only
trouble is, every board has a different thermal profile so you should make a
batch of X number of a certain board using one level of pre-heat followed by
another with its level and so on.

However they were not sufficiently organised to be able to do this so they use
some 'average pre-heat' value.

However that pales into insignificance when I discovered what they were up to
at an earlier stage in the process.

We had a LOT of dry/cold joints from them. Prosound / Ahuja. Avoid.

Graham

 

[Eeyore]

Smitty Two wrote:

Jim Adney <jadney@vwtype3.org> wrote:
Eeyore wrote:

I prefer 800 degrees. Always have done. Esp with small tips. The idea is to
get
the soldering done as fast as quickly, not leave the joint cooking until the
solder finally melts.

I have to disagree. 700 F is already way above the melting point of
the solder. If you need more heat you might want to use a larger tip,
with greater thermal mass, but higher temps are much more likely to
damage the board.

I'm with Graham on this one. I threw all the Wellers in the dumpster a
few years back (tired of fixing them all the time) but when we did use
them we used nothing but 800 degree tips.

Now we've got another brand of iron with dial adjustable temperature and
keep them set at 800, also. For the hobbyist or even repair tech,
waiting two or three seconds for a small joint to heat up might be
acceptable, but for production work it isn't.

And as far as board damage, higher temps are much *less* likely to
damage the board, and the components, because dwell time is drastically
reduced.

Finally as to reduced tip life at higher temps, that cost is offset by
increased efficiency 1000 times over.

Indeed. Worrying about the cost of an occasional replacemtn tip means someone's
priorities are way askew. Stinks of the MBA culture actually. They never can see
the wood for the trees.

Grahm

 

[Eeyore]

N Cook wrote:

Arfa Daily wrote in message

One of the main reasons that manufacturers are having so much trouble with
the stuff, is that they have to run their soldering processes at a higher
temperature. This then brings them close to the maximums that some of the
components can tolerate for any length of time, so they have to compromise
and run the process at a slightly reduced temperature. That is fine until
you have to solder a connector or power semiconductor - particularly one
that is mounted on a heatsink, and that is where many lead-free bad joints
are occuring. Trust me, if manufacturers didn't *have* to run their
processes at a higher temperature, with all of the implications of that,
including a higher energy useage, to cope with lead-free, then they
wouldn't

Is all your info available collated together on a website somewhere. ?

Any comments on the following
If replacing new (ROHS) components to old boards (leaded solder) then scrape
off most of the hard mirror-like finnish on the leads before tining with and
then soldering with Pb-Sn solder

21Century RoHS boards , repair of but not production (heavy solder usage),
use silver solder, or is that likely to lead to as much a problem as mixing
RoHs and PbSn solder.

I read somewhere a while back that the military, aerospace and telecoms guys
were sending components out to de 'de-tinned' of lead free and re-tinned with
the proper stuff.

Crazy ! Otherwise you can get problems.

Graham

 

Eeyore wrote:
<snip>

I still use 700s because of the problem of 800s burning out
quicker when
left idling all day,

Well I simply don't let it idle all day. It's guarenteed to give
those nasty
'inter-metallic oxides' in the long term anyway that make re-
tinning near
impossible. A guy I used to work with would switch on the bench
(including iron)
and maybe not use the iron all day. Whenever I noticed, I'd switch
it off again.
Why waste electricity anyway ?

Graham

Stop screwing around with Weller if you're serious about soldering and
production certainly qualifies. Get a Metcal. It's ready to use in 10
seconds and with the vastly superior heating element, you don't need
to push it to 800 and live with the temperature 'coasting' down every
time it touches a cold connection. The heating element in the Metcal
_is_ the temp sensor and it's as close to the tip as you can get. Try
one of those and your Wellers will be like both of mine - in a box in
the garage.

So far I've bought 8 Metcal systems, initially one for me personally
and then 6 soldering stations and 1 de-soldering station at work. eBay
is great for this. The cheapest power unit I got was $10 and since it
was local (Los Angeles), I picked it up on the way home and paid no
shipping.

G˛

 

[Yukio YANO]

Eeyore wrote:

On that issue, though, what are your thoughts on the use of brass
turnings as a tip cleaner vice a dunk in the swamp? I switched over to
the bowl of brass a while ago and now prefer it to the damp sponge.

I tried one of those brass things and it was useless IMHO. It left loads of crap on the
tip. Use a moist Weller sponge every time.

Graham

I switched to using "Stainless Steel" Pot scrubbers nearly 40 years ago,
NOT "Steel wool" It's stuffed into the bottom of the soldering iron
Holder, just a twist inserting or removing the Iron is usually enough
to keep the tip clean. To clear a really dirty tip, a few swipes on the
outside of the holder is sufficient. Do not use "Steel Wool"! it will
dissolve in the hot solder to form all sorts of crud and scraps will
stick to the magnetic tips.

Yukio YANO

 

[Jim Adney]

On Wed, 27 Aug 2008 20:23:20 +0100 Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:

William Sommerwerck wrote:

Good soldering technique will not give cold solder joints,
regardless of the tip temp. High tip temp is probably
a poor way to overcome poor technique.

I would absolutely dispute that statement.

As would I. The temperature has to be at least high enough to bring the
solder to its "liquidus" state. (Which is one of the reasons eutectic solder
is preferable.)

Using a higher temp iron will certainly pump more heat into the
joint in a given time, but it also results in more temp difference
across the joint, so you may be more likely to get what looks
like a good joint on the heated side, but with little penetration.

This is bilge.

Quite. The total stress on the components is in fact likely to be be LESS.

Before you guys all continue to pile on, you might want to actually
read the link that Arfa posted. They are quite emphatic about avoiding
the proceedure you're all supporting. Read it. It's informative.

-
-----------------------------------------------
Jim Adney jadney@vwtype3.org
Madison, WI 53711 USA
-----------------------------------------------

 

[Jim Adney]

On Wed, 27 Aug 2008 20:24:37 +0100 Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:

Ever heard of thermal inertia ?

If you actually mean specific heat, yes.

-
-----------------------------------------------
Jim Adney jadney@vwtype3.org
Madison, WI 53711 USA
-----------------------------------------------

 

[Jim Adney]

On Wed, 27 Aug 2008 11:28:31 +0100 "Arfa Daily"
<arfa.daily@ntlworld.com> wrote:

And many boards now actually state that they are lead free or "PbF" on the
silk screening. As far as I have been able to tell, it's not so much about
mixing different types of lead-free alloys, which may or may not contain
small traces of other metals such as silver, but more a case of not mixing
lead-free with leaded solder.

The board labeling certainly helps with the lead vs. lead free
problem, but the link you posted also states that the different lead
free alloys should not be mixed. The do seem to imply that mixing lead
in with the lead free is worse, but I can't tell whether the problem
there is an engineering problem or a legal one.

To Jim. All of my experience with this stuff is from a service rather than
production point of view. You are of course right that manufacturers use
wave or reflow soldering, and have done for many years. The point I was
making about lead-free joints and Weller TCPs at 700 deg, versus
manufacturers' joints, was perhaps not grammatically well-made. What I was
basically saying was that the manufacturers, with all of their expertise and
expensive production soldering equipment, still can't get to grips with the
stuff themselves, and are still producing equipment littered with bad joints
from day one. So, if you are making consistently good 'production' joints in
lead free, using 700 degree hand soldering equipment designed way way before
any eco-prat had ever come up with the concept of taking the lead out of
solder, then you (your company) are doing, on average, better than the big
boys.

We should all remember that the big boys also had soldering problems
before the lead free mandate. AFAIK, those problems were mainly due to
trying to run the boards over the wave soldering machines too fast. I
doubt that present day production quotas are any less compelling.

As far as heat and temperature are concerned, I take your point that they
are not the same thing, and I don't think that I am confusing the two. They
are however, inextricably linked to one another by external influences.
Energy, in the form of heat, is what has to be put into a body in order to
raise its temperature. All solder has to have its temperature raised to the
point where its liquid state becomes suitable for making a soldered joint,
and then maintained at that temperature until the joint is completed. The
temperature at which this condition occurs for lead-free solder, is higher
than that of leaded solder. If you are just making small joints, then this
is of no consequence, and a 700 degree tip is fine for the job. With a
leaded joint - even a large one that causes the tip temperature to drop by a
few degrees - that drop is again of little consequence, as there is plenty
of temperature 'overhead' available from a 700 deg tip. However, with
lead-free, 50 degrees of that overhead, have already gone, so if a joint is
any bigger than 'small', the additional temperature drop at the tip, caused
by the joint leaching heat from it, results in a less than adequate tip
temperature being maintained, to correctly complete the joint. The result is
a bad or 'cold' joint. A 700 degree tip simply cannot maintain enough
heatflow into the solder, to keep it at a sufficient temperature to do a
'good job' on anything other than a small joint, and this is particularly
the case where a 'typical' repair workshop tip of small dimensions is used.

I'm glad to see that you do understand the difference between heat and
temperature, and the causes and effects of heat flow, but we won't
settle this argument until someone can post the actual melting point
of 63/37 and the solidus/liquidus of some of the lead free solders.
ISTR that the good old eutectic stuff melted at something like 370 F,
but I wouldn't bet on it. I'm pretty sure that it's somewhere below
400 F, so another 50 F is not such a big deal.

I have a repair service for a particular board which uses lead-free, and I
see many of them where the shop that's sending it back to me, have attempted
some rework or component replacement, and it's quite obvious that they have
been trying to use their normal leaded soldering equipment to do the job,
with the inevitable consequences.

Cooper appears to recommend tools that start at the same temp, but
have greater thermal mass and better thermal conductivity to the work.
They also have some additional recommendations which I have not tried.

Weller sells a preheat "table" which heats your board from the bottom
while you solder on top (or vice versa.) This would clearly help
produce joints that have been heated to an even temperature, and
Weller makes the point that it reduces stress in the finished joint.
They also sell a special iron which floods the work with an inert gas
while you solder.

Both of these seem pretty burdensome and extreme to me.

I can accept what Cooper say about not being tempted to increase the tip
temperature, but I think that they are probably talking more about not going
up far enough to get the same 'feel' with lead-free, as with leaded. Most
commentators on the subject, including soldering equipment manufacturers,
agree that a higher nominal tip temperature is required to work reliably
with lead-free.

I don't find an actual tip temperature in the Weller link, but they do
say to use the lowest temperature possible. Since I find that I have
no trouble (really!) soldering with a 700 F tip, and everyone in our
lab uses the same irons with the same alloys, I see no reason why
anything hotter would be justified.

It is also quite true that I do not work under a quota requirement,
nor am I paid by the joint, so I don't mind if the joint takes 3
seconds instead of 2. OTOH, I'm not really much aware of any change in
my soldering habits or technique since I used my first WTCP iron in
about 1977.

My earlier irons, starting with an American Beauty in about 1955,
required much different skills, and I was young and foolish then, so
when I go back and look at some of that work I often have to "tidy" it
up a bit.

One of the main reasons that manufacturers are having so much trouble with
the stuff, is that they have to run their soldering processes at a higher
temperature. This then brings them close to the maximums that some of the
components can tolerate for any length of time, so they have to compromise
and run the process at a slightly reduced temperature. That is fine until
you have to solder a connector or power semiconductor - particularly one
that is mounted on a heatsink, and that is where many lead-free bad joints
are occuring. Trust me, if manufacturers didn't *have* to run their
processes at a higher temperature, with all of the implications of that,
including a higher energy useage, to cope with lead-free, then they wouldn't
...

I think they would do just as well if they ran more slowly at lower
temps, but they probably find that is even more expensive than the
higher temps.

We won't really know the answer until we know the actual liquidus
temps of the Rohs solders. A check here gives us some facts to
consider:

http://kester.com/en-US/technical/alloy.aspx

I note that most of these range from 420 to 450 F, with 2 eutectic
alloys that melt at 430 and 440. 700 F seems like plenty of overhead
for working at those ranges, at least to me.

-
-----------------------------------------------
Jim Adney jadney@vwtype3.org
Madison, WI 53711 USA
-----------------------------------------------

 

[Eeyore]

Arfa Daily wrote:

I don't have info particularly collated anywhere, but if you want to contact
me off group with an address that's monitored for input, I'll send you a
copy of the article, which contains references to where I got info, and who
from. I don't think that there is any particular need to remove the surface
of RoHS compliant components' leads. I seem to recall reading somewhere that
most component leads are now tin plated, as in coated in neat tin, rather
than being 'tinned' with any kind of solder, as they were in the past. A
coating of pure tin should not cause any problems when used with a
conventional SnPb solder.

The military etc are still worried because of potential tin whiskers with
closely spaced device leads.

There are known examples of such inter-lead shorts and they can support up to
30mA I read somewhere IIRC. I had a fantastic picture of one once. It shorted
out a *crystal*.

Graham

 

[Eeyore]

Arfa Daily wrote:

"Eeyore" wrote
Jim Yanik wrote:
"Arfa Daily" wrote
"Eeyore" wrote
Arfa Daily wrote:

I still use 700s because of the problem of 800s burning out quicker
when left idling all day,

I don't let that happen and re-tin and wipe the tip regularly. I
probably 'waste' as much solder as I use !

Plus Farnell IIRC sells some aggressive (iron) oxide remover that can
help restore a 'damaged' tip. It comes in a little circular tin.

I have some, and jolly good it is too, although I wonder just how much
that's eating away at the tip, as well ...

Did you never ever use ancient pure copper tips ? That's why Multicore
added a small percentage of copper to some of their solders.

IIRC,that has some powdered solder mixed in with the flux.
It cleans AND tins.

That's the stuff.

(of course,AFAIK,it's not lead-free....)

Damn good news !


Aha ! When I first started in the business way back when dinosaurs roamed
the countryside, we used Adcola irons with a bakelite 'tortoiseshell'
handle, and a neat spiral of what looked like tinned copper wire wound right
up the length of the business end. Those irons used a solid copper tip, and
we always used 'Savbit' cored solder with them. This solder had added
copper, as you say.

That was the stuff. Couldn't remember the name.

The best thing about those solid copper tips, was that
you could file them to any shape that suited your work, without compromising
their performance. A quick touch up with a file fully restored the soldering
tip, which would then tin immediately, and stay tinned until you flicked the
solder blob off, ready to start using it. The solid copper tips were, as I
recall, remarkably long lived, and could be filed into almost non-existence,
before they needed to be replaced.

Oh yes I remember well.

Using irons like that really taught you
the skills of good soldering, skills which stay with you your whole life.
The Antex CN15s and 25s from the same era also had solid copper tips, and
the same things applied. They were the first ones that I can remember
changing over to (first nickel ??) and then iron plating of the bits.

Yup. The Antex C15 was my first 'serious' iron for working on miniature
components like TO-18 transistors. I recall BC109s were 6s/6d from Henry's Radio
back then and building my first pre-amps from the Mullard Audio and Radio
applications book.

Once
that plating wore through though, there was no rescuing the tip, even though
it was copper inside. Touching it up with a file was a one day only fix, and
a new bit was rapidly required. Odd that. perhaps the copper used was a
softer grade or something, once they had it 'protected' by the plating ...

Possibly just purer ?

Graham

 

[Eeyore]

Jim Adney wrote:

Eeyore wrote:
William Sommerwerck wrote:

Good soldering technique will not give cold solder joints,
regardless of the tip temp. High tip temp is probably
a poor way to overcome poor technique.

I would absolutely dispute that statement.

As would I. The temperature has to be at least high enough to bring the
solder to its "liquidus" state. (Which is one of the reasons eutectic solder
is preferable.)

Using a higher temp iron will certainly pump more heat into the
joint in a given time, but it also results in more temp difference
across the joint, so you may be more likely to get what looks
like a good joint on the heated side, but with little penetration.

This is bilge.

Quite. The total stress on the components is in fact likely to be be LESS.

Before you guys all continue to pile on, you might want to actually
read the link that Arfa posted. They are quite emphatic about avoiding
the proceedure you're all supporting. Read it. It's informative.

My experience says otherwise. I'll have to time how long it takes to solder say a
1/4W resistor but it's certainly less than the 3 seconds or so some have mentioned
with 700F tips.

Plus note my post about those cold joints that plagued an amp design that just
'went away' with 800F tips.

Graham

 

[Eeyore]

Jim Adney wrote:

Eeyore wrote:

Ever heard of thermal inertia ?

If you actually mean specific heat, yes.

And what you mean is 'heat capacity' which is NOT the same thing !
Although it's value depends on specific heat too.

" Heat capacity (symbol: Cp) — as distinct from specific heat capacity —
is the measure of the heat energy required to increase the temperature
of an object by a certain temperature interval. "
http://en.wikipedia.org/wiki/Heat_capacity

Graham

 

[Andy Cuffe]

On Wed, 27 Aug 2008 00:55:17 -0500, Jim Adney <jadney@vwtype3.org>
wrote:

I've never used one of those, but I've wondered how they would be. I'd
be concerned that they would wear thru the tip plating quickly and
lead to early death of the tips. Have you noticed any of that?

-

I also use one of those, and if anything, my tips last longer.
Andy Cuffe

acuffe@gmail.com