Soldering questions

[Bill_F]

I've built quite a few boxes now and thought I was starting to figure out soldering. But there are a couple of questions I have and you boys always have the answers.  :lol:

1. I've read two different opinions on this one. Do you touch a dab of solder onto the tip of the iron right before you make contact with the component and board. I've read this helps make a better connection with the tip and the object being soldered. Therefore its helpful. I also just read (in the authors words) "DO NOT carry the solder to joint on the tip of the iron, this almost invariably produces a bad joint."  Which one is correct?

2. Do you clean your tip on the sponge or whatever cleaning element you use after every joint? Or is that not necessary.

Thanks everyone for your patience and willingness to answer all these questions.

Bill

[Samuel]

There is a difference between the tip being tinned and "carrying solder to the joint". Having the tip be tinned with a bit of solder greatly improves the iron's heat transfer. So you always want a bit of solder on the tip. The point of this is to help heat transfer so you can quickly heat the two pieces of metal you are attempting to solder. Ideally, you should be able to push your solder into the joint, not the iron, which should now be hot enough to melt the solder and bond to it once it solidifies.

[petemoore]

Im gettin good at using just the right amount of solder and heat, don't get 'messy tip' like I used to.
 When I do get messy tip, I quickly/lightly flip it off of there with the nearest component package [away from me closing my eyes at tip contact] ...lol...don't try this at home. Very unprofessional I know and still I do it !
 Starting a joint with large clods of crud on the tip I don't like.
 I try to leave it 'moist' not drippy, but with at least a film of solder on it to 'accellerate' the temperature rise on the cold leads/pad.
 A really dry tip can take 'forever' to conduct enough heat to the leads to reach melting point of the solder.
 I took two days finding the 'thick' [6 leads, big pad, and related solder] coldsolder on a SS phazer, I reheated the whole area...future places like this I will leave till I got all the leads in then solder them all at once with 'tip to two points' on the pad.

[petemoore]

Best kwik tip I know.  preplanning OA wires [the way they'll lay] makes it easier to do these when perfing...allow tip access theory

[bobbletrox]

I've heard that soldering iron heat kills diodes and transistors, so now I'm paranoid about ruining my components.

[Bill_F]

OK. I understand that you don't want a completely dry iron and you want it tinned. But from what I understand tinning the tip is something you only have to do once. What I'm talking about is that some people suggest you just touch the solder to the tip (that has aready been tinned) right before you make contact with the joint. I"ve been doing this and it seems to help heat the joint up much quicker. Now I'm wondering if I'm producing bad joints this way.

[Peter Snowberg]

Here's my 2 cents... pardon any repetition.

"Tinning" involves keeping a coating of oxide free solder on the tip to preserve the base metal, and to allow for good thermal transfer to the connection you're about to make.

If the iron has been sitting for any length of time, the solder on the tip will oxidize so you should re-tin it. If you insure the whole tip is covered with fresh solder right before you go to make some connections, and then tap off any excess, you're left with a clean surface that's ready to transfer heat very efficiently.

Touch that nice clean and tinned tip to the joint, and within a second or two it should have heated the junction to the point where the material you are soldering will melt the solder to make the junction. You don't really want to melt the solder on the iron tip, but right next to it instead.

For soldering a PC board with a good iron, it should take no more than 1 second or so to heat the junction to the point where it will then melt the solder. If your iron is too small, or not hot enough, it may take longer and this is where you run the risk of damage. With my iron set to 555 degrees F and .025" solder, each connection takes a total of less than 2 seconds. If your iron is too hot, the tip will get an oxide coating much faster and make it harder to get a good, fast joint. For regular soldering, I always work with a temperature of 600 or less. For production work, I like 650-675. I never go hotter than that except for a really special cases that suck big amounts of heat. (ground planes, pot backs)

Having unoxidized solder touching your work is about the most important thing. The rosin is triggered by heat, so you want the work to be hot otherwise the rosin will be cooked and stop working before it hits the material it's supposed to work on.
The iron is just for heating the work. The solder is for melting into the work.

Take care,
-Peter

[Paul Perry (Frostwave)]

There used to be a good "how to solder" on the net (now lost AFAIK) wher the guy called putting a tiny bit of solder on the iron "THE TRICK". And I think, that when I solder, I do touch the soder to the iron as I am touching the solder to the component. And that little bit of solder definitely helps the heat flow to the component. Of course, if you add a huge blob to the iron, then you cool everything down, which is the reverse of what you want. But you shoudn't be using 'blobs' anyway!
What certainy DOESN'T work, is putting solder to the iron a few feet away & carrying it across, because all the flux burns off & then nothing works.
I think that is why people say, don't 'carry' the solder to the joint on the iron.
It is (unfortunately) like PnP, what works for some may not for others.
And so far as thermal damage to components is concerned, you do less damage with a hot iron than one whic isn't hot enough, because with a hot iron you get in & out FAST. Rather than sitting around waiting for the joint to heat up. When I'm paranoid, I tin the component legs beforehand, then they will solder very fast.

[Bill_F]

There used to be a good "how to solder" on the net (now lost AFAIK) wher the guy called putting a tiny bit of solder on the iron "THE TRICK". And I think, that when I solder, I do touch the soder to the iron as I am touching the solder to the component. And that little bit of solder definitely helps the heat flow to the component.

That's exactly what I've been doing  :lol: and I've found it very helpful. Then I read this thing yesterday that says ""DO NOT carry the solder to joint on the tip of the iron, this almost invariably produces a bad joint." That concerned me. I guess what were doing is not carrying the solder to the joint. Maybe some people try to put enough solder on the tip itself to actually make the joint. I could see where that would cause some problems.

I love this forum, it is nice to have a place to talk about the little things like this that really do matter in a big way.

Thanks again guys for all your help.

[Ansil]

an easy way to learn without messing up a good circuit. is to practice soldering and desoldering some junk radios or computer boards..  it is a great way to see what you need to work on as there are lots of wonderful joints around you to see what you are doing.