Author Topic: A Question About Soldering  (Read 759 times)

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glakedylan

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A Question About Soldering
« on: May 25, 2014, 02:31:31 PM »
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A Question About Soldering

I hope I am posting this in the correct thread. If not, please feel free to move it to where it would belong.

When soldering, and all the soldered materials are metal (and perhaps computer board ties, as in hand laying turnouts and crossings)...is there a way to move quicly over the soldered places with a portable soldering torch (like those used in plumbing) to help flatten and blend in those lumps of solder that accumulate. The only way I know to remove such is by filing. I am wondering if there is a better way, especially when the lumps are located on the rail near bottom?

respectfully for all the expert soldering folks here
(but then I suppose the experts may not end up with lumps!)
Gary L Lake Dillensnyder
"...that each may live for all,
and all may care for each..."

robert3985

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Re: A Question About Soldering
« Reply #1 on: May 27, 2014, 12:26:21 AM »
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A Question About Soldering

I hope I am posting this in the correct thread. If not, please feel free to move it to where it would belong.

When soldering, and all the soldered materials are metal (and perhaps computer board ties, as in hand laying turnouts and crossings)...is there a way to move quicly over the soldered places with a portable soldering torch (like those used in plumbing) to help flatten and blend in those lumps of solder that accumulate. The only way I know to remove such is by filing. I am wondering if there is a better way, especially when the lumps are located on the rail near bottom?

respectfully for all the expert soldering folks here
(but then I suppose the experts may not end up with lumps!)

Gary L Lake Dillensnyder

There are a couple of tricks to not getting blobs of solder.  However, if you've got blobs, then your soldering technique isn't up to snuff, and you're either applying too much solder or you're not fluxing before applying heat.

There are a lot of ways to remove solder blobs.  An easy way is to heat the joint and blow on it while the solder is molten.  That can lead to minor burns both on you, your clothes and on any carpet in the vicinity, so it's best done outdoors.  Of course, if you've got blobs on track that's attached to your layout, maybe blowing isn't such a great idea...but it WILL still work.

Another way is to go to your local Radio Shack and pick up some desoldering wick (or braid) which is braided copper wire in a mesh that you lay on top of your solder blob, heat it up with your iron and it "wicks" up the excess solder.  Pretty easy, and it usually leaves enough solder at the joint so it's still good. These little spools of copper mesh run less than five bucks per spool.  Sometimes you need to flux the wick, but most of the time not.

Yet another way is, while you're at Radio Shack, to buy a desoldering iron for around 15 bucks.  It's a 45 watt iron with a big red rubber bulb attached to it which either blows or sucks up the solder once it's molten again.  I don't know, I don't need one.

The problem with the blobs is usually because you're applying too much solder.  There are several ways to keep from doing that:

(1) Flux the joint you're going to solder, Cut a small piece of solder and lay it so it's touching both pieces of metal you're going to solder (such as the edge of the foot of your rail and the PCB tie it's sitting on), and is laying in the flux.  Heat the opposite side of the joint touching both the rail and PCB tie simultaneously...and when the solder suddenly melts...it'll flow under the foot of the track, heading towards the heat, and both the PCB tie and the rail will be nicely soldered.  Your iron needs to have a clean and tinned tip for this to work.

(2) Squash the end of your solder with flat-nose pliers, and split the flattened solder down the middle with an Xacto knife so you've got a tiny "Y" on the end of your solder.  Flux and heat your joint so that both pieces of metal are simultaneously heated and touch one finger of the "Y" to where both pieces of metal are coming together (if it's track, touch the opposite side of the rail from where you're applying your 30 Watt soldering iron with a clean, wedge tip).  Once again, as soon as the solder melts, take it away, and apply about a second's more heat to the joint...drawing the solder towards the heat as capillary action sucks it between the two pieces of metal.  Don't let the pieces move until the solder has cooled and hardened.  Your iron needs to have a clean and tinned tip for this to work.

(3) Use fine solder rather than big diameter solder, and remove the solder as soon as it melts and flows between the two pieces of metal which have been previously cleaned and fluxed.  Your iron needs to have a clean and tinned tip for this to work.

To solder track (from code 80 to code 40) I use a simple 30 Watt Archer soldering iron with a wedge tip, which is in a stand with a wet sponge and a small container of tinning solution.  For EVERY joint, I make sure the tip is clean and tinned, and the joint is fluxed.

I flux every track joint with the finest non-acid flux known to man, which is Superior No. 30 Supersafe Soldering Flux (gel) and is available here:   http://bart.ccis.com/home/hn/   Get some.  It will turn you into a soldering expert.  Seriously.  I am not kidding.

I also use their lead-free solid core solder.

Whatever you do, DO NOT use ANY acid solder that's used for plumbing, such as "Plumber's Honey"...it will eat your solder joints, the ties around them, and your PCB ties.  BAD STUFF.  Oh yeah, it's "great" for soldered copper pipe joints attached to your sinks and toilets made using a big torch,  but it is not for model work.  I speak from experience.   

I always remove the oxidation from the copper on the PCB tie by wiping it a few times with a pink pencil eraser, and I do the same to the foot of my rail when building turnouts.

If there is a place you don't want solder to go, mark it with a 2B pencil.  Solder won't go to a surface covered with pencil lead.

Using a torch on PCB material is a BAD IDEA.  It will cook the fiberglass and delaminate the copper.  It's a big no no.

Hope this helps you out.

« Last Edit: May 27, 2014, 12:43:14 AM by robert3985 »