Forums

Soldering newbie

Started by M. Hamed April 2, 2013
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 m=
e rework about 50 PCBs at once when he was on vacation. That involved solde=
ring a little SMT cap using tiny little wire to a nearby IC pin. Most of th=
e boards worked, but the job looked horribly ugly.

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

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

The questions at hand for now are these:=20

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

2) Soldering guides tell you to always heat the joint not the solder. Whene=
ver 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 rea=
lly hot enough I have to find a sweet spot on the tip that is hot enough an=
d 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 rece=
ntly with success. The problem is that I'm not sure if it's better than a s=
ponge 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 mu=
ch 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 provid=
ed 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 feel=
ing bored may be they can share their experience. I know I probably can spe=
nd hours scouring internet forums and getting all sorts of conflicting info=
rmation. I thought I may get some direct answers here! THANKS.
On Tue, 02 Apr 2013 16:04:14 -0700, M. Hamed wrote:

> 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?
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. 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. (Don't use a temperature controlled iron unless you already own it, or have long-term access. They're instantly addictive. It'll be like the first time someone took the butter knife out of your hand and gave you a real screwdriver -- you won't want to go back).
> 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?
It could be. But it could just be that the tip isn't clean, or isn't tinned enough. Dirt, oxidized solder, and burnt flux don't transmit heat well. What you're really trying to do is to make sure that the whole joint is hot enough to melt solder -- you can do a perfectly good solder joint by dribbling solder on it, then reheating everything. But unless you're really good, you can't tell the difference between a good joint done this way and a poor joint done this way. Melting the solder onto the metal to be soldered is a 100% reliable way of making sure it's at soldering temperature.
> 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.
If the tip is clean, you've done a good job. I haven't used copper wool much (mostly when someone shoved a soldering iron under my nose). All of the people that I know who solder Really Well use a sponge. 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.
> 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.
Electronic solder comes with flux built in -- the solder is actually a hollow tube filled with flux (or, sometimes, a tube with more than one hole, all filled with flux). If you've been using anything other than flux intended for electronics then you've been using the Wrong Stuff. Flux for electronics (usually called "rosin flux") is very mild, and the stuff you're expected to solder is easy to solder to. Flux for mechanical assemblies ("acid flux") is much more harsh -- which is what you want when you need to solder to steel or other difficult materials, but it causes corrosion if it's not cleaned all the way off of your job, and it's almost impossible to clean electronics 100%. -- My liberal friends think I'm a conservative kook. My conservative friends think I'm a liberal kook. Why am I not happy that they have found common ground? Tim Wescott, Communications, Control, Circuits & Software http://www.wescottdesign.com
On Tue, 2 Apr 2013 16:04:14 -0700 (PDT), "M. Hamed"
<mhdpublic@gmail.com> wrote:

>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?
Your iron is too hot. You need one of the temperature-controlled ones. Metcal are the best.
> >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?
I poke the tip into the intersection of the board and the part, and apply solder to the 3-way intersection. That wets everything and transfers a bunch of heat fast.
> >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.
It's to remove excess solder and burnt, crusty old flux. Sponge works.
> >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.
Usually the flux in rosin-core electronic solder is all you need. I rarely add additional liquid flux. -- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation
On Tue, 02 Apr 2013 17:29:07 -0700, John Larkin
<jlarkin@highlandtechnology.com> wrote:

>On Tue, 2 Apr 2013 16:04:14 -0700 (PDT), "M. Hamed" ><mhdpublic@gmail.com> wrote: > >>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? > >Your iron is too hot. You need one of the temperature-controlled ones. >Metcal are the best.
Oy! You'll give the poor guy a heart attack. 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.
"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



On Tue, 2 Apr 2013, M. Hamed wrote:

> 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 >
> 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. >
On Apr 2, 3:04=A0pm, "M. Hamed" <mhdpub...@gmail.com> wrote:

> 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 boar= ds for things like transistor amplifiers for my crystal radio. I have littl= e 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 sol= dering 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 al=
ways 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 proba= bly 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 b= urns 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. Whe=
never I do this, it seems it takes forever for solder to melt. It also seem= s that the pointy part of the tip (as they always show in drawings) isn't r= eally 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 re=
cently 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 spon= ge. 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 transist=
or radio kit completely without flux. But also the type of solder they prov= ided with the kit seemed really good, I thought may be the solder has it al= l.
> > I know this has been answered a million times before but if someone is fe=
eling bored may be they can share their experience. I know I probably can s= pend hours scouring internet forums and getting all sorts of conflicting in= formation. 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
"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





"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 


On 2013-04-03, Rich Webb <webb.ra@example.net> wrote:
> On Tue, 02 Apr 2013 17:29:07 -0700, John Larkin
>>Metcal are the best.
> 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