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Soldering Question ... Something I've Always Found Very Challenging

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Posted by nscsxcrrailfan on Tuesday, July 6, 2010 10:15 PM
Essentially what I'm worried about is trying to get a good solder connection without melting ties while avoiding a cold solder joint. Question: How hot does Nickel Silver have to get before it will melt solder on its own? Is it too hot for the plastic ties? Is it o.k. to use flux as a crutch since without out we get hot nickel silver but melted ties?
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Posted by howmus on Tuesday, July 6, 2010 10:14 PM

nscsxcrrailfan
I watched your video and what I think I'm doing wrong is worrying way too much about getting the rail hot. With model RR track you just can't get the rail very hot without melting ties. ALSO ... Is it much of an issue if I just always apply a bead of solder to the iron and rely on separate flux to do my soldering? I'm asking this because I know that the flux boils away when the solder is applied from the iron's tip instead of from a separate spool.

 

The addition of a good rosin flux (I am using the liquid flux from Micro Mark) is really the secret of the technique.  The big reason many sources tell you not to do it the way I do is that the rosin burns away as soon as you put the solder on the iron.  The use of flux at the joint being soldered allows the solder to flow into the joint as the rosin does its job of cleaning the area to be soldered.  That is also why I don't worry too much about pretinning the wire or the rail.  It all happens at once. BTW, sometimes I will add a bit more solder to the joint, but usually there is plenty of solder in the drop on the iron to do the job.  Oh, and the rail gets very hot, right at the spot where the joint is made.  It will then spread down the rail.  But since you used enough heat to do a good joint in a small spot, the temp doesn't get so hot it will melt ties nearby.  As I mentioned in the Video, yes, you may damage the little fake "spike right under the place you are making the joint, but that is all.  Practice, practice, practice!

The black stuff that accumulates on the iron is burnt rosin, BTW.  I clean the iron frequently with the same brass brush you saw in the video.

One other thing.  This technique I only use for electrical work!  I do something much more "traditional" when building Fast Tracks Turnouts or other soldering work.......Wink

Ray Seneca Lake, Ontario, and Western R.R. (S.L.O.&W.) in HO

We'll get there sooner or later! 

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Posted by nscsxcrrailfan on Tuesday, July 6, 2010 9:36 PM
howmus

nscsxcrrailfan
A couple of years ago, I started using a technique where I would apply rosin flux on the end of the track feeder, put some rosin solder 40/60 on the tip, and then apply that to the wire, which would result in a tinned wire (I set the iron at slightly below half on the amount of power). I would then take some flux and put a very small amount using a toothpick on the side of the rail where I wanted the feeder (of course I cleaned it first with alcohol and a toothpick). I then put some more solder on the iron tip and touched the tinned wire to the rail and touched the iron to the wire and rail causing the solder on the wire, tip, and the flux to all combine creating a fairly good joint. This technique has worked for me

 

I'll play the devils advocate here and tell you that your original technique is right on base.  The trick is using separate rosin flux. I use a 25w Weller using a similar technique taught to me by a man who made a living repairing sound equipment.  He learned it from his father who learned it in the Air Force.....  I clean the rail and do the entire joint in one easy process.  Yes, I get perfect results every time and I can solder a rail feeder onto code 70 flex in less than a second.  Here is a short video of a clinic I gave  last year for the local NMRA.  http://s66.photobucket.com/albums/h259/slow_rr/SLOW_RR_II/?action=view&current=SolderingTech2.flv

On the layout I have now I have soldered around 6,000 joints.  Guess how many have failed.... (0)  And... no melted ties.  I do not use heat sinks.  Sometimes I pretin, but not always.

A little theory -  Heat is transferred to the joint mostly where the metal of the iron is contacting the metal of the metal being heated.  Remember that air is an insulator.  A dry iron has very little contact area, so the heat is transferred slowly allowing the heat to travel down the track melting ties as it goes, but won't easily get hot enough where the joint is to melt the solder or if it does you may get a cold solder joint.  Having a small drop of solder on the tip of the iron increases drastically the contact surface allowing heat to be transferred quickly from both the drop of solder and the entire (very hot) iron.  The result is a lot of heat right where you need it.  You are done quickly and before the heat travels away from the joint to do damage.  That phenomenon is the reason some people recommend a larger iron and a flat tip on the iron.  More contact area, quicker, better, and safer results.

I watched your video and what I think I'm doing wrong is worrying way too much about getting the rail hot. With model RR track you just can't get the rail very hot without melting ties. ALSO ... Is it much of an issue if I just always apply a bead of solder to the iron and rely on separate flux to do my soldering? I'm asking this because I know that the flux boils away when the solder is applied from the iron's tip instead of from a separate spool.
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Posted by nscsxcrrailfan on Tuesday, July 6, 2010 9:24 PM
Also, I tried alligator clips as some have suggested. The problem is that when I use them they won't grip very good to my Code 55 rail, and the only way I can get them to hold onto the wire is to have one grip into the insulation which melts as soon as the iron touches the wire/rail.
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Posted by nscsxcrrailfan on Tuesday, July 6, 2010 9:21 PM
O.k., I went back and did some more practice. This is what drives me crazy. The second technique that I thought was better worked good on an old turnout I had however it melted the ties like crazy on a piece of flex track I practiced on. So, I turned the heat down from 5 to 4 and the same problem occurred. I shortened the time to 1 second and still ended up with melted ties. In addition, I'm afraid to turn the iron up to 4 or 5 now because the tip turns purple/blue. When I put solder on it the flux just evaporates instantly and I'm left with just a little bead of solder metal on the end. I cannot tin the tip with the iron set above 3 1/2. The last technique I tried was to turn the iron down to 3 1/2, tin the wire, use as little solder and flux as possible, and hold the iron on there for 1-2 seconds. Question: I've been told that the tip I'm using is too big and is transferring too much heat. It's the original one that came with the iron. It's wide and looks like a flat screwdriver head. However, I would think that by using a pencil tip that I would have to hold the iron on there longer to get it up to the right temp resulting in more melted ties. Then again, perhaps the bigger tip is spreading the heat out more than necessary resulting in melted ties. Any thoughts on this??? Also, one thing I've noticed is that if I take my iron tip and just place it on the rail, it takes 5-10 seconds before the ties start melting. However, when I use the flux and solder, they melt sometimes almost instantly. I wonder if the flux is getting really hot and spreading out, carrying the heat to the ties and melting them. Also, in general (Audio equipment, home electrical, layout wiring, etc...) how important is it that the wire be hot before you apply solder? Many times I have to touch the solder against the iron tip and make sure to use flux to get a good solder connection. Should I always make sure the wire is hot enough to melt the solder on its own without having to touch the solder to the tip or is it o.k. for the wire to simply be very warm?
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Posted by abbieleibowitz on Tuesday, July 6, 2010 8:51 PM
All of the techniques mentioned throughout this thread work and really, there are few differences between them. I don't have a magic solution that will blow anyone away, but I have found that the key to soldering is to get the piece hot quickly and get out just as fast. So my most important contribution is that I always have a wet paper towel nearby when I solder feeders to track and when I solder rails. I've had melted ties even with heat sinks, but I have had the best success by rapidly cooling the joint by pressing the wet towel to the track as soon as I take the iron away. The little "sizzle" tells me it's cool. I remember reading somewhere that if you cool the joint too quickly you can get a brittle solder joint that won't hold, but that has never been a problem for me using this technique. Abbie
Tags: Soldering

Lefty

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Posted by dstarr on Tuesday, July 6, 2010 8:38 PM

 Try a pair of alligator clips from Radio Shack.  They do double duty, they hold the feeder wire in place, and they act as heatsinks to reduce the amount of tie melting.   I clean my rail with a wire brush in the Dremel. Tinning the feeder is helpful, it carries solder to the joint and doesn't need a third hand to do it.  Rosin flux is good.  Unless the rail is ultra clean, and the Gods smile upon you, the rosin core of the solder won't give enough flux for a clean joint.  Forty watts is on the small side for soldering to rail.  I use a 200 watt Weller soldering gun myself.  

   You want the tip of the iron or gun to be tinned, covered with silvery molten solder.  A tip wet with molten solder will flow more heat, faster, into the rail than a black, dry, and crusty tip will.  As for how long to heat the joint, you look at the solder.  When the joint is hot enough, the solder will melt, wet the rail, and flow into a  smooth drop shape.  Soon as that happens, the joint is hot enough and you can remove the heat.  The cool solder joint must stay shiny.  A white frosty look is called a cold solder joint and must be reheated before it is reliable. 

 

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Posted by howmus on Tuesday, July 6, 2010 6:21 PM

nscsxcrrailfan
A couple of years ago, I started using a technique where I would apply rosin flux on the end of the track feeder, put some rosin solder 40/60 on the tip, and then apply that to the wire, which would result in a tinned wire (I set the iron at slightly below half on the amount of power). I would then take some flux and put a very small amount using a toothpick on the side of the rail where I wanted the feeder (of course I cleaned it first with alcohol and a toothpick). I then put some more solder on the iron tip and touched the tinned wire to the rail and touched the iron to the wire and rail causing the solder on the wire, tip, and the flux to all combine creating a fairly good joint. This technique has worked for me

 

I'll play the devils advocate here and tell you that your original technique is right on base.  The trick is using separate rosin flux. I use a 25w Weller using a similar technique taught to me by a man who made a living repairing sound equipment.  He learned it from his father who learned it in the Air Force.....  I clean the rail and do the entire joint in one easy process.  Yes, I get perfect results every time and I can solder a rail feeder onto code 70 flex in less than a second.  Here is a short video of a clinic I gave  last year for the local NMRA.  http://s66.photobucket.com/albums/h259/slow_rr/SLOW_RR_II/?action=view&current=SolderingTech2.flv

On the layout I have now I have soldered around 6,000 joints.  Guess how many have failed.... (0)  And... no melted ties.  I do not use heat sinks.  Sometimes I pretin, but not always.

A little theory -  Heat is transferred to the joint mostly where the metal of the iron is contacting the metal of the metal being heated.  Remember that air is an insulator.  A dry iron has very little contact area, so the heat is transferred slowly allowing the heat to travel down the track melting ties as it goes, but won't easily get hot enough where the joint is to melt the solder or if it does you may get a cold solder joint.  Having a small drop of solder on the tip of the iron increases drastically the contact surface allowing heat to be transferred quickly from both the drop of solder and the entire (very hot) iron.  The result is a lot of heat right where you need it.  You are done quickly and before the heat travels away from the joint to do damage.  That phenomenon is the reason some people recommend a larger iron and a flat tip on the iron.  More contact area, quicker, better, and safer results.

Ray Seneca Lake, Ontario, and Western R.R. (S.L.O.&W.) in HO

We'll get there sooner or later! 

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Posted by gandydancer19 on Tuesday, July 6, 2010 5:59 PM

 The object is to get a good bond and a joint that looks wetted.  (Just like wetting in scenery.)  The faster the better as long as the result is good.

What I do is this:  (I use a temperature controlled station and heat it to the equivalent of a 40 watt iron, about 700 degrees F.)

Clean the rail with a scratch brush.  Strip the wire and bend it to the shape needed to lay against the rail.  Apply a small amount of rosin flux.  Wipe the irons tip on a wet sponge then apply it and the solder to the rail as close as I can to the feeder wire.  (I apply the solder to the tip of the iron first then move it to the rail.)  When the solder melts, move the iron to include the feeder wire.  As soon as I see the solder flow on the feeder wire I remove the iron. 

If I can't get the wire to stay against the rail, I will apply solder to the tip and then apply the iron to the rail on the flux.

When I apply the solder to the iron first and it melts, it then flows to the rail.  When it flows to the rail, it carries or conducts the heat to the rail which helps heat it up more quickly.   This heat transfer is of prime importance, just like starting with a clean area to be soldered.

Elmer.

The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.

(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.

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Posted by bpickering on Tuesday, July 6, 2010 5:59 PM

luvadj

I use heat sinks on both sides of the rails when I solder, but occasionally, I still get a melted tie or two. I've found get it hot and cooled it down again as quick as possible works for me.

Heat sinks of one form or another. I typically use a couple of clamps, one on either side of the feeder. I've also recently read about using wetted tissue paper, being a similar concept to the wet cotton balls. However, the key is what luvadj said- get the heat on as quickly as possible, get things melted properly, and let it cool off.

I use a 45W iron for track-work, so the 40W is probably in the right range. 15W or 25W will probably take so long heating to melting temperature, that even with heat sinks, the surrounding material will heat up to the point where ties start melting.

Brian Pickering "Typos are very important to all written form. It gives the reader something to look for so they aren't distracted by the total lack of content in your writing." - Randy K. Milholland
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Posted by Hamltnblue on Tuesday, July 6, 2010 5:56 PM

make sure the surface you are soldering to is nice and clean.

Pre drill the hole for the feeder. Then use Solid wire for the feeder and do a small bend at the tip.  About a half inch from the feed kink the wire so that the feeder is pressed into the rail when you lower the wire. That way you don't have to hold it.  It will hold itself.  Use flux on the joint.  When soldering place the iron at the spot where the wire and track join.  Use a very thin solder so that it melts quickly.

Springfield PA

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Posted by luvadj on Tuesday, July 6, 2010 5:43 PM

I use heat sinks on both sides of the rails when I solder, but occasionally, I still get a melted tie or two. I've found get it hot and cooled it down again as quick as possible works for me.

Bob Berger, C.O.O. N-ovation & Northwestern R.R.        My patio layout....SEE IT HERE

There's no place like ~/ ;)

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Posted by nscsxcrrailfan on Tuesday, July 6, 2010 5:40 PM
Also ... I forgot to mention that I am in N scale using Atlas Code 55 track.
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Soldering Question ... Something I've Always Found Very Challenging
Posted by nscsxcrrailfan on Tuesday, July 6, 2010 5:38 PM
Hi, I've been in model railroading since 2004, and I have always had trouble with soldering. I've tried all kinds of techniques with different irons. Every piece of advice I found seemed to require 3 hands, one holding the iron, one holding the solder, and one holding the feeder, which I've found impossible to do. The iron I've settled with now is a Weller 5-40watt soldering station (red and comes with a yellow sponge). A couple of years ago, I started using a technique where I would apply rosin flux on the end of the track feeder, put some rosin solder 40/60 on the tip, and then apply that to the wire, which would result in a tinned wire (I set the iron at slightly below half on the amount of power). I would then take some flux and put a very small amount using a toothpick on the side of the rail where I wanted the feeder (of course I cleaned it first with alcohol and a toothpick). I then put some more solder on the iron tip and touched the tinned wire to the rail and touched the iron to the wire and rail causing the solder on the wire, tip, and the flux to all combine creating a fairly good joint. This technique has worked for me, but everywhere I read, everyone recommends heating the rail first. I tried all sorts of techniques trying to heat the rail and every time, either the solder wouldn't melt or the ties would melt. So, I kept experimenting and finally came up with another technique that I want everyone's opinion on. Every piece of advice I read about recommends using maximum heat to quickly heat the rail and wire without melting the ties. So, I set the iron on maximum (40 watts) and cleaned it using the wet sponge that came with it. Then, I applied a tiny amount of flux to the spot where I want my feeder. Next, I cut the feeder wire and stripped the end of it. Once the iron was heated to maximum temperature, I applied a very small amount of solder to one side of the tip (I'm using the original flat screwdriver looking tip that came with it). I then took the wire and placed it on the rail where the flux was and applied the iron's tip to the wire and rail and heated it for 2 seconds using the side of the iron without any solder, then I turned the iron over where the solder was attached and re-applied the iron, this time the solder flowed into the feeder joint very nicely. I have discovered that using this technique seems to result in a harder to break connection and results in a smooth flowed out solder connection. I tried this same technique at 3 and 5 seconds and both times I ended up with melted ties. An individual on Youtube recommended laying down wet cotton balls on both sides of the place to be soldered to help prevent melted ties. I haven't tried that yet, although I plan on doing so soon. So, is this method of soldering o.k. or am I likely to run into problems down the road? Should I heat the rail and wire longer than 2 seconds (at 40watts)?

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