Soldering newbie

[M. Hamed]

I am not new to soldering. I have some soldering experience. I have built aradio kit with no soldering problems whatsoever. I have made little boardsfor things like transistor amplifiers for my crystal radio. I have little surface mount experience, but in a moment of extreme courage, my boss let me rework about 50 PCBs at once when he was on vacation. That involved soldering a little SMT cap using tiny little wire to a nearby IC pin. Most of the boards worked, but the job looked horribly ugly.

The reason I consider myself still a newbie, is that successes are not always repeatable, and failures are not always avoidable.

I have read numerous guides on the Internet but some things really don't click. I thought I could start this thread to ask questions that will probably be obvious to some but still not very clear to me.

The questions at hand for now are these:

1) Soldering guides always recommend you to tin the tip of your iron with fresh solder before starting on a joint. Every time I do this the solder burns and discolors. Is that normal or am I doing something wrong? Do I have to be really fast before solder burns?

2) Soldering guides tell you to always heat the joint not the solder. Whenever I do this, it seems it takes forever for solder to melt. It also seems that the pointy part of the tip (as they always show in drawings) isn't really hot enough I have to find a sweet spot on the tip that is hot enough and then touch it to the wire. Do I just have a bad iron?

3) Can I use copper wool instead of a wet sponge? I have been using it recently with success. The problem is that I'm not sure if it's better than a sponge or not. I'm not even sure of the function of the copper or the sponge.. I know it's for wiping the tip clean but it's hard for me to gauge how much better cleaning the tip actually provides.

4) When to use flux and when is it not important? I soldered the transistorradio kit completely without flux. But also the type of solder they provided with the kit seemed really good, I thought may be the solder has it all.


I know this has been answered a million times before but if someone is feeling bored may be they can share their experience. I know I probably can spend hours scouring internet forums and getting all sorts of conflicting information. I thought I may get some direct answers here! THANKS.

 

[Phil Allison]

"M. Hamed"


1) Soldering guides always recommend you to tin the tip of your iron with
fresh solder before starting on a joint. Every time I do this the solder
burns and discolors.

** The iron is too hot, get an adjustable or temp controlled one.

It is possible to use a light dimmer with a cheap iron to reduce the temp.


2) Soldering guides tell you to always heat the joint not the solder.
Whenever I do this, it seems it takes forever for solder to melt.

** When you touch the tip against a joint, immediately apply a little solder
to tip so the hot solder carries the heat around.

It also seems that the pointy part of the tip (as they always show in
drawings) isn't really hot enough I have to find a sweet spot on the tip
that is hot enough and then touch it to the wire. Do I just have a bad iron?

3) Can I use copper wool instead of a wet sponge?

** Brass wool is best.


4) When to use flux and when is it not important? I soldered the transistor
radio kit completely without flux. But also the type of solder they provided
with the kit seemed really good, I thought may be the solder has it all.


** Use only flux cored, 60:40 tin lead solder for electronics.

Avoid the lead free kind.



.... Phil

 

[Michael Black]

I am not new to soldering. I have some soldering experience. I have
built a radio kit with no soldering problems whatsoever. I have made
little boards for things like transistor amplifiers for my crystal
radio. I have little surface mount experience, but in a moment of
extreme courage, my boss let me rework about 50 PCBs at once when he was
on vacation. That involved soldering a little SMT cap using tiny little
wire to a nearby IC pin. Most of the boards worked, but the job looked
horribly ugly.

The reason I consider myself still a newbie, is that successes are not
always repeatable, and failures are not always avoidable.

I have read numerous guides on the Internet but some things really don't
click. I thought I could start this thread to ask questions that will
probably be obvious to some but still not very clear to me.

The questions at hand for now are these:

1) Soldering guides always recommend you to tin the tip of your iron
with fresh solder before starting on a joint. Every time I do this the
solder burns and discolors. Is that normal or am I doing something
wrong? Do I have to be really fast before solder burns?

If the iron wasn't tinned right at the beginning, then the tip gains some
coating that causes the solder to just roll off.

I have a vague memory of this happening once, but I can't remember what I
did. I do know that when you have properly tinned the tip from the
beginning, some residue can build up, and you need to work at clearing
that up so the solder doesn't ball and roll off when heated, but spreads
out over the tip.

I also have a vague memory of burning solder on one iron, yet it seems
more related to an untinned tip. Because it's not like I've bought
endless packs of solder over the years, and the same solder works fine on
my soldering gun, which is much hotter than the irons I've had in forty
years. I think maybe I ended up with some bad solder, or solder rated at
a lower temperature. But it's been decades.

2) Soldering guides tell you to always heat the joint not the solder.
Whenever I do this, it seems it takes forever for solder to melt. It
also seems that the pointy part of the tip (as they always show in
drawings) isn't really hot enough I have to find a sweet spot on the tip
that is hot enough and then touch it to the wire. Do I just have a bad
iron?

The guides all say that, but most people do melt some solder on the tip as
it is held against the joint. The melted solder helps the heat to flow.
Once there is a bit of solder on the joint, the heat flows more easily.

3) Can I use copper wool instead of a wet sponge? I have been using it
recently with success. The problem is that I'm not sure if it's better
than a sponge or not. I'm not even sure of the function of the copper or
the sponge. I know it's for wiping the tip clean but it's hard for me to
gauge how much better cleaning the tip actually provides.

No. Except really cheap irons (the tips will last a very short time),
soldering iron tips have been plated for decades. If you use something
metallic to clean it, you may clear off the plating. The plating is a
great thing, it protects the tip. Without it, the tip will decay after a
relatively short time, while all the plated tips I've had last forever.

You don't want a lot of solder on a tip, at least when you are soldering,
yet keeping some solder on the tip protects it. So you pull your iron out
of the stand, briefly wipe it on the sponge (paper towels work too, I
don't even bother dampening them) before you solder, and then before you
put the iron back in the stand (at least if it will be sitting there for a
while), add a bit more solder.

So it's primarily to get the excess solder off, something you don't need
steel or copper wool for.

There are times when there's sort of a carbon buildup, I guess solder left
on the tip too long without being wiped off, and that takes some work to
clear off, but no actual filing or need for steel wool. But the build up
happens because the excess solder isn't regularly wiped off.

That said, again if you don't tin the tip properly at the start, there
will be later problems.

4) When to use flux and when is it not important? I soldered the
transistor radio kit completely without flux. But also the type of
solder they provided with the kit seemed really good, I thought may be
the solder has it all.

The solder has flux built in. Melting a bit of solder on the tip of the
iron helps to spread the flux onto the joint you are trying to solder.
Same thing happens with old solder, the flux has long gone, you try really
hard to heat up the joint but no success. Melt a bit of solder against
the iron on the joint, and the new solder provides flux for the heat to
flow, so the old solder melts like it should.


Michael

 

[Bill Bowden]

I am not new to soldering. I have some soldering experience. I have builta radio kit with no soldering problems whatsoever. I have made little boards for things like transistor amplifiers for my crystal radio. I have little surface mount experience, but in a moment of extreme courage, my boss letme rework about 50 PCBs at once when he was on vacation. That involved soldering a little SMT cap using tiny little wire to a nearby IC pin. Most of the boards worked, but the job looked horribly ugly.

The reason I consider myself still a newbie, is that successes are not always repeatable, and failures are not always avoidable.

I have read numerous guides on the Internet but some things really don't click. I thought I could start this thread to ask questions that will probably be obvious to some but still not very clear to me.

The questions at hand for now are these:

1) Soldering guides always recommend you to tin the tip of your iron withfresh solder before starting on a joint. Every time I do this the solder burns and discolors. Is that normal or am I doing something wrong? Do I haveto be really fast before solder burns?

2) Soldering guides tell you to always heat the joint not the solder. Whenever I do this, it seems it takes forever for solder to melt. It also seems that the pointy part of the tip (as they always show in drawings) isn't really hot enough I have to find a sweet spot on the tip that is hot enough and then touch it to the wire. Do I just have a bad iron?

3) Can I use copper wool instead of a wet sponge? I have been using it recently with success. The problem is that I'm not sure if it's better than asponge or not. I'm not even sure of the function of the copper or the sponge. I know it's for wiping the tip clean but it's hard for me to gauge how much better cleaning the tip actually provides.

4) When to use flux and when is it not important? I soldered the transistor radio kit completely without flux. But also the type of solder they provided with the kit seemed really good, I thought may be the solder has it all.

I know this has been answered a million times before but if someone is feeling bored may be they can share their experience. I know I probably can spend hours scouring internet forums and getting all sorts of conflicting information. I thought I may get some direct answers here! THANKS.

Another trick is to coat both surfaces with solder before joining them
together and clean the surface of the leads. So, if you want to solder
two resistor leads together, use an exacto knife to scrape the
resistor leads clean and then apply a thin coat of solder to each
lead. Then put the resistor leads together and solder the joint. You
may not need any solder on the iron, just heat the leads and they will
melt together..

-BIll

 

[Phil Allison]

"Bill Bowden"

Another trick is to coat both surfaces with solder before joining them
together and clean the surface of the leads. So, if you want to solder
two resistor leads together, use an exacto knife to scrape the
resistor leads clean ...

** You should never have to do that.

Only very old and badly corroded leads require scraping.


..... Phil

 

[Phil Allison]

"M. Hamed"

I know this has been answered a million times before but if someone is
feeling bored may be they can share their experience. I know I probably can
spend hours scouring internet forums and getting all sorts of conflicting
information. I thought I may get some direct answers here!


** There are two common reasons why beginners have problems soldering:

1. They are using a shit awful soldering iron.

2. They are using lead free or flux free solder.

Hamed, like most, has not revealed what HE is using.



..... Phil

 

[notbob]

Oy! You'll give the poor guy a heart attack.

No kidding. Metcals are insanely overpriced, even if they now have a
station in the mid $200 range. Jes get a Hakko FX888. You can get
'em fer < $85 and they have a great range of tips, even down into SMT
sizes.

nb

 

[M. Hamed]

Thanks for all the help.

Discolors how? If it turns brown it's not the solder -- it's the flux.
If it turns gray, then the solder is oxidizing. The flux getting a bit
brown isn't that bad, but either one of these things happening is an
indication of your iron being too hot. You probably can't get away from
this easily without using a temperature-controlled iron.

Yes, it is brownish with some blue. You're right it's most likely the flux.
I do have a temperature controlled station. I looked last night at the temperature setting and it was about 750-800.

If you have tip cleaner or a damp sponge that'll work well, too. The tip
needs to be tinned, but more importantly it needs to be clean.

So do I need to clean every time before applying solder?

They (and I) use a _damp_ sponge -- if it's dripping, it's way too wet:
it'll freeze the solder on the tip and stick the gunk on solid.

Yes, I am realizing now my sponge had too much water. I tried the scotch bright cleaning sponges but I didn't know they had extra chemicals on them. Ihad a hard time finding one that doesn't have stuff added. The one that came with the soldering station is in a bad shape.

Usually the flux in rosin-core electronic solder is all you need. I
rarely add additional liquid flux.

I see the experts at work use flux all the time. My guess is that it's needed for 1-Lead free soldering, 2-Surface mount components with very small pitch?

** When you touch the tip against a joint, immediately apply a little solder
to tip so the hot solder carries the heat around.

This is more or less what I used to do and solder seemed to melt easier this way. However I read in many places where they tell you this is a big NO NO.

If the iron wasn't tinned right at the beginning, then the tip gains some
coating that causes the solder to just roll off.

But even with tinning the burnt flux still coats the tip. I will retry reducing the temp as everyone is suggesting.

The guides all say that, but most people do melt some solder on the tip as
it is held against the joint. The melted solder helps the heat to flow.
Once there is a bit of solder on the joint, the heat flows more easily.

Oh, Thank you! That was my experience too. I always felt guilty about it though

You don't want a lot of solder on a tip, at least when you are soldering,
yet keeping some solder on the tip protects it. So you pull your iron out
of the stand, briefly wipe it on the sponge (paper towels work too, I
don't even bother dampening them) before you solder, and then before you
put the iron back in the stand (at least if it will be sitting there for a
while), add a bit more solder.

So you're saying tinning should be done after soldering the joint, not before? Could you describe how you typically tin the tip? Just touching it to the solder wire seems to concentrate solder on one side of the tip. If I wipe it with the sponge, I don't know if it stays there or not.

** There are two common reasons why beginners have problems soldering:
1. They are using a shit awful soldering iron.
2. They are using lead free or flux free solder.
Hamed, like most, has not revealed what HE is using.

Phil, I do not use lead free, except if I have to do some soldering at work.. Mainly when the job is too easy it is embarrassing to send to the tech. Iuse leaded solder with my home projects (which haven't been so many).

Once the OP has started breathing again, he might want to look for
something like <http://www.howardelectronics.com/xytronic/lf369D.html>
It's not a knock-off brand and is reasonably inexpensive (as these
things go). Some (of many more) alternates are over at
<http://www.circuitspecialists.com/soldering-stations> where they have
house-branded stations. Haven't tried these but I've purchased other
stuff from them in the past w/o complaints.

Rich, I have this: http://www.circuitspecialists.com/csi-station1a.html

 

[Phil Allison]

"M. Hamed"

Phil Allison wrote:

** When you touch the tip against a joint, immediately apply a little
solder
to tip so the hot solder carries the heat around.

This is more or less what I used to do and solder seemed to melt easier this
way. However I read in many places where they tell you this is a big NO NO.


** I have just seen a site where the writer gives this and other WRONG
advice too.

It is a common mistake to apply solder to the tip and then carry it to the
joint - but that is NOT my advice.

The idea is to AID the tip in heating the joint FAST by *re-tinning* it as
you go.

So, after applying the tip, add a dab of solder - then as the solder flows
around add a more to the joint itself.

Good soldering is done very quickly, blink and you will miss it.

A slow motion, close up vid would be good.



.... Phil

 

[Phil Allison]

"Phil Allison"

This is more or less what I used to do and solder seemed to melt easier
this way. However I read in many places where they tell you this is a big
NO NO.


** I have just seen a site where the writer gives this and other WRONG
advice too.

It is a common mistake to apply solder to the tip and then carry it to the
joint - but that is NOT my advice.

The idea is to AID the tip in heating the joint FAST by *re-tinning* it as
you go.

So, after applying the tip, add a dab of solder - then as the solder
flows around add a more to the joint itself.

Good soldering is done very quickly, blink and you will miss it.

A slow motion, close up vid would be good.

** This one will do nicely....

.... Phil

 

[Phil Allison]

"Phil Allison"

** This one will do nicely....

** You may have to copy and paste the link into YouTube.



..... Phil

 

[Bill Bowden]

   So is a small solder pot where you can clean & re-tin the leads at
the same time.  I used one for years to clean the pins on used ICs, and
old stock components.  It's easier to deflux loose components than ones
in an assembly.

Remember the old wire-wrap boards? No solder, just simply twist the
wire around the square post and the sharp edges made a gas-dry joint.
I know a guy who sells glue and does an impressive demo at the swap
meets. He glues rubber, glass and metal in seconds and claims you can
twist two wires together and just use his glue without any solder. I'd
like to try some of it, but he sells the stuff for $20 an ounce. But
it is amazing.

-Bill

 

[[email protected]]

Yes, and I remember looking for bad wraps, and having to solder wire
to hundreds of pins when the wire corroded. If you want real fun, try
replacing a bad IC socket where every pin has three levels of wrap, and
most are daisy chained. A repair that would take minutes on a PC board
can take days when you have to remove & replace over a hundred wires.

You clearly had incompetent people running the show. If properly
done, WireWrap is as (or more), reliable as soldered connections and
you don't daisy-chain the stuff. You should never have to pull more
than three wires to replace one. At one time mainframes were all
WireWrapped (millions of connections) and were *quite* reliable.
Three-high was a no-no, as well, though that was probably for other
reasons (impedance). The pins were shorter than some, designed for
two wraps only (but a third was easily possible).

 

[Michael Black]

You clearly had incompetent people running the show. If properly
done, WireWrap is as (or more), reliable as soldered connections and
you don't daisy-chain the stuff. You should never have to pull more
than three wires to replace one. At one time mainframes were all
WireWrapped (millions of connections) and were *quite* reliable.
Three-high was a no-no, as well, though that was probably for other
reasons (impedance). The pins were shorter than some, designed for
two wraps only (but a third was easily possible).

I suspect that's some of the issue, the commercial stuff was the mainstay
of wire wrap. I've never heard of much trouble with commercial stuff,
which may mean it was outside the hobbyist realm, or it may mean it works
fine.

Certainly when it hit the hobbyists, about the time Byte arrived, it was
treated as a serious thing, so surely the example of commercial wire
wrappted equipment was there.

But once in the hobby world, it likely wasn't the same thing. Yes, you
could buy actual guns, but for many it was done manually, which I can see
would be a source of trouble. Also, those who hadn't had experience
likely had problems, just like the person beginning to solder doesn't yet
have the experience to know they have bad joints.

I suspect many didn't grasp the concept, and indeed we saw a lot of
intermediate work, wire wrap sockets and wire wrap wire, but a cursory
wrap around the socket pin and then solder, as if people didn't trust the
notion of wire wrapping. I admit that as someone who had already been
soldering, the notion of just twisting the wire around the socket pin
didnt' seem secure.

Michael

 

[[email protected]]

I suspect that's some of the issue, the commercial stuff was the mainstay
of wire wrap. I've never heard of much trouble with commercial stuff,
which may mean it was outside the hobbyist realm, or it may mean it works
fine.

Certainly when it hit the hobbyists, about the time Byte arrived, it was
treated as a serious thing, so surely the example of commercial wire
wrappted equipment was there.

But once in the hobby world, it likely wasn't the same thing. Yes, you
could buy actual guns, but for many it was done manually, which I can see
would be a source of trouble. Also, those who hadn't had experience
likely had problems, just like the person beginning to solder doesn't yet
have the experience to know they have bad joints.

Unlike most hobbyists, it has to be wrapped tightly. ;-) Seriously,
that's the major problem, getting enough tension on the wire as it's
being pulled around the post so the wire bites into the edges. The
other major problem I saw was stripping. Many would nick the wire.
Bad news for reliability. We had special strippers that looked like
long-nosed pliers with a nick in the jaw (not the blade). Some didn't
know that they were special tools and would use them as long-nose
pliers. One turn of a nut and they were shot. At $100 each, people
got a little protective of their tools.

I suspect many didn't grasp the concept, and indeed we saw a lot of
intermediate work, wire wrap sockets and wire wrap wire, but a cursory
wrap around the socket pin and then solder, as if people didn't trust the
notion of wire wrapping. I admit that as someone who had already been
soldering, the notion of just twisting the wire around the socket pin
didnt' seem secure.

I wouldn't have expected that it was as good as it was, either. It
does take some skill, then so does soldering.

 

[[email protected]]

The software for programming a wire-wrap machine was non-trivial. I
did it once.

Read punched cards to get the net list. Each card has an IC or
connector name, pin number, and net name.

I did that for manual wrap, though used a file (then spreadsheet) for
technician use. They then would put in every other wire in a net,
finally adding the ones in between. That way, if something changed
(or broke), one didn't have to rip the whole net out.

Sort all that by net and look for obvious errors.

I used to do that with PCB netlists. Tools have gotten much better,
though. It's amazing the errors that can be seen by the eye without
looking at the actual data.

Read another deck that maps pins to physical coordinates

Do a "traveling salesman" algorithm to minimize wire length in each
net

Unless order made a difference.

Sort by level so there are no cross-level wraps

Yep. Our techs did that by doing every other wire in a net, then
coming back and fill in the 2nd levels.

Sort by position to mimimize head travel

Handle color coding, maybe

Output the G-codes and reports.

Wire wrap was awful, in many ways. I don't miss it a bit.

I prefer it to dead bug, though it's expensive. I used to have some
pretty complicated WW boards (one with >6000 wires - memory busses
nave lots of wires , before PCBs got cheap.

 

[Jasen Betts]

I know a guy who sells glue and does an impressive demo at the swap
meets. He glues rubber, glass and metal in seconds and claims you can
twist two wires together and just use his glue without any solder. I'd
like to try some of it, but he sells the stuff for $20 an ounce. But
it is amazing.

take some wires, take home a sample glued joint?

 

[Bill Bowden]

   Yes, and I remember looking for bad wraps, and having to solder wire
to hundreds of pins when the wire corroded.  If you want real fun, try
replacing a bad IC socket where every pin has three levels of wrap, and
most are daisy chained.  A repair that would take minutes on a PC board
can take days when you have to remove & replace over a hundred wires.

Yes, it could be a problem. I remember a case where we had an
inexperienced person doing a R&D wire-wrap job with little
supervision. Turned out there was a short from +5 to ground, so we
decided to apply a small current from a PS to see if the offending
wire would get hot and reveal itself. We cranked up the PS to about 20
amps and nothing got hot, so we had to throw away the whole board
since there were too many shorts across the PS.

-Bill

 

[Tom Del Rosso]

2) Soldering guides tell you to always heat the joint not the solder.
Whenever I do this, it seems it takes forever for solder to melt. It
also seems that the pointy part of the tip (as they always show in
drawings) isn't really hot enough I have to find a sweet spot on the
tip that is hot enough and then touch it to the wire. Do I just have
a bad iron?

You need a chisel tip instead of that 'pointy' tip.

The point of a conical tip never makes enough contact.

 

[Phil Allison]

"Tom Del Rosso"

You need a chisel tip instead of that 'pointy' tip.

The point of a conical tip never makes enough contact.

This vid ( I posted earlier) shows how to use a pointy tip to solder
regular components like 1 amp diodes to a PCB with plated through holes.

The side of the tip is used and solder is constantly re-applied to the tip.



..... Phil