Soldering Woes

[gottcent]

I recently bought a new Weller soldering iron, #SP40L, rated at 40 watts. I let it warm up about 10 minutes, brushed each side of the tip against a damp sponge,  and then tried to coat the tip with a bit of solder to "tin" it. (I used NC Core solder identified as "lead-free" and "0/0 flux," purchased from the same electrical supply store where I bought the iron.)

Instead of coating the tip, however, the solder just formed a ball and dropped down onto the sponge. Undaunted, I proceeded to attempt a small soldering job by applying the iron's heat to the joint and then placing some solder on the joint. The solder would not adhere, however, but instead kept sticking to the hot tip.

After several similar attempts, I let the iron cool and then replaced the tip with another one from Weller, and went through the same procedures. Unfortunately, I kept getting the same results. Since then I've tried to use this equipment and solder on several other small jobs of a type which I've had no trouble soldering before, but I keep having the same problems.

Any thoughts?

John Gottcent

[Firelock76]

Try a different kind of solder, not all solders are created equal. You don't say what it is you're trying to solder, if it's two wires or something similar try a solder intended for electrical use.  Also, try wiping the surfaces to be soldered with a flux.

Not that I'm a genius at this myself.  However, some guys out there can solder a piece of spagetti to a mosquitos nose, so hopefully you'll hear from them.

[servoguy]

Get some real solder.  The lead free stuff doesn't work and is not reliable.  The military will now allow it in their stuff.  Make sure you get solder with a rosin core.  Radio shack should be a good source.  

[lionelsoni]

I agree--60-40 (60 percent tin, 40 percent lead) rosin core solder.

[CKCECB]

I have same iron, and it's worked well for me.  Mine even came with a small roll of solder that's good.  My only gripe is that the large chisel tip it came with pitted after a couple of dozen jobs.  I'm user a smaller chisel tip and it works much better in my opinion.  And I use rosin core solder with lead like the others have posted. 

[cwburfle]

I also find that lead free solder is difficult to use. I only use it for plumbing,.
For that application it helps to have a MAP torch, and the type of flux used does make a big difference.

For electrical work, I use rosin core solder, usually 60/40 which is readily available at Radio Shack.
I prefer thinner solder (It comes in a number of different thicknesses)

I also have a bottle of liquid rosin flux and a tin of paste rosin flux. These are used on very rare occasion in tiny amounts to wet the old solder on an old terminal that is being resoldered.  I've been using the same two containers for over ten years, and both are still just about full.

 

I use Solder Wick to remove excess solder from terminals before re-using them.

[Nationwidelines]

Actually, I do not agree with what the others have told you.  I learned to solder while being an electronics technician in the Navy and on delicate electronic equipment that was designed to run nuclear reactors and using a rosin/flux core solder was a no-no on this type of equipment.  I never use a flux core solder on the prewar trains that I repair. 

 

As for your problems, sometimes I find it necessary to sand the two pieces of wire that I am trying to solder in order to get all the crap/coatings off of the ends of the wire and make a good connection, as the solder will bond to a clean surface better.  I also find that sometimes I have to let the soldering iron sit on the wires and heat them up for a length of time prior to applying the solder.

 

That being said, I looked at my spool of solder and it is so old that the label has fallen off, so I cannot say what sort of mix of tin/lead it is, but I suspect it is not lead free, just no rosin/flux core.

 

NWL

[cwburfle]

I learned to solder while being an electronics technician in the Navy and on delicate electronic equipment that was designed to run nuclear reactors and using a rosin/flux core solder was a no-no on this type of equipment. 

It does not surprise me to learn that rosin flux is not desirable on delicate electronic equipment. There are many different types of flux  Here is a link to Kester solder, you can read up on the different types of solder and flux if you so desire:

http://www.kester.com/products/?type=featured&limit=20&filters%5B%5D=&filters%5B%5D=&filters%5B%5D=&filters%5B%5D=17&filters%5B%5D=

 

 

[TRAINCAT]

As a past Navy Fire control technician who then went into civilian electronics manufacturing and service I say when it comes to toy trains most jobs are fine with Rosen core solder. Only surface mount components require different solder and its not likely any of you here will be doing that. That requires liquid solder flux. The bottom line is you do NOT ever want to use ACID flux like is used for plumbing applications. You should use the Rosen flux solder. You can solder without it, but it makes a better, cleaner connection and makes solder flow more easily.
Roger

[sir james I]

Over the years I find that 60/40 works very well for toy train use. You need a hot iron and clean parts.

[gottcent]

Thanks, guys. I was wondering if I was using the wrong kind of solder. I used to use rosin core 60/40, but the guy at my electrical supply store (not Radio Shack, but a usually reliable local store) talked me into trying the NC stuff. I think I'll go back to 60/40.

BTW--to the person who wrote that he had the same iron and that the chisel tip pitted--the same thing happened to me. I bought a new tip and invested in a solder tip cleaner--looks like a golden colored ball of steel wool into which you wipe the hot tip--seems to be helping.

John

[M. Mitchell Marmel]

At work (we do the occasional surface mount component repair) we use Weller soldering stations set to 720 degrees, liquid flux and the gold solder tip cleaner (which we call 'the burning bush').  I suspect that your iron isn't generating enough heat for the non-lead solder... 

Mitch

[cwburfle]

BTW--to the person who wrote that he had the same iron and that the chisel tip pitted--the same thing happened to me. I bought a new tip and invested in a solder tip cleaner--looks like a golden colored ball of steel wool into which you wipe the hot tip--seems to be helping.

Other than junior high school shop class, I do not have any formal training in soldering. I have been doing it for a long time though.
I find that tips tend to pit more when solder is fed onto the tip, as opposed to heating up the work, and letting the solder melt directly onto the work.

When I am using a Weller soldering gun, my favorite tips are the plain copper ones.
When I am using an iron, I also prefer copper tips.