CP Executive train in Albany

CP Executive train in Albany

Monday, December 11, 2017

Soldering wires to M.E. switch frogs

There are certain projects I really enjoy in model railroading, and certain ones I dread. Laying track and ballasting are by far my favorite things to do. Wiring, especially soldering, it probably my least favorite (though if I ever attempted backdrop painting, it would jump to the top). Soldering is supposed to be easy: take a clean, hot iron + properly tinned wire + apply heat to the thing to be soldered and not the solder itself = clean, shiny joint. Yeah, right.

Except that it isn't always so good. Many times when I am trying to get the solder to melt and it just balls up on the iron or on the wire, not melting and distributing itself. Or, the iron never seems to get hot. For years I couldn't understand it. Then, I decided to do some research online and I came to the realization that I was going about it all wrong. Honestly, though, it wasn't all my fault!

First, there is a bit of conflicting information out there. Take soldering iron tips. Some people say to clean them with fine sandpaper to make them shine when they get cruddy. Others say not to because the tips have a fine copper coating and once removed the tips are ruined. Do you use a wet sponge to clean the tip, or a wire mesh? Some places say to get a 40-50 watt pencil iron for soldering feeder wires, and others say 15-25 watts, and a few prefer big soldering guns. And do you use separate flux or rely on just the solder. Who is right?

Turns out, probably everyone in different situations. For me, not knowing what those situations were resulted in poor results every time I tried to solder. So, I went back to the basics. I bought a new Weller soldering iron station. It has an iron holder (that coiled thing), a place for a wet sponge (not shown in the picture), a knob to adjust the amount of voltage to the iron, and an on/off switch. It is very handy, my iron doesn't roll around and I can easily see if I left it turned on. But it wasn't enough.

Then started buying the proper wire for the job. It used to be that I would grab whatever type (solid, stranded) of wire I had handy even if it was thin wire with thick outside insulation, or heavy stranded wire with ends that would go everywhere no matter how hard you twisted them together. Now, I buy it in rolls online in various gauges (14 for bus wires, 22 for feeders) in the colors I need. It sucks when you run out of green or blue wire at the wrong time, but I stop what I am doing and purchase more instead of substituting something else. As a result, my wiring has improved too. But it wasn't enough.

I used to never use flux, but then I found I had some plumber's flux (Oatey #95) lying around and used that (I have no idea what will happen with those joints but the container didn't have the word "acid" on it). Then, I went out and bought Mininatronics / Miniatronics (note the spelling online, and on the package) rosin based flux and that worked fine. But it wasn't enough.

Finally, I switched my solder from really heavy diameter rosin-core stuff to thinner silver bearing solder. Was it expensive? A bit, but not that much. And, the joints are much stronger. I also purchased some really thin 0.020" diameter solder for times when I need just a little. And finally, it was enough.

Why am writing this? Because recently I did something I thought would be impossible based upon horror stories I had read online. According to some, soldering a wire to the underside of a M.E. turnout just cannot be done. Other people have said it is tough but possible. In fact, lots of people have done it. So what's the story?

I decided to try it myself. Truth be told, it was holding up my track laying. I couldn't lay my switches if the wires to the frogs weren't pre-soldered to the base of the frogs (some have said you can solder to the visible side of the frog casting, but I didn't want to go there). And, if the switches didn't get installed I couldn't really do anything else. Humm. So, I sucked it up and figured at least one soldering attempt couldn't hurt.

I first flipped the switch over and scraped away some excess tie plastic around the frog "button," that little circle thing you need to solder to. It was recommended to do this, as if the plastic melts and gets on the button it would contaminate the area and make soldering difficult. Then, I used the point end of a need file and scraped the button until it shone. You really cannot file/sand it clean by going sideways, as it is recessed. Poking it with the file worked though.

Next, I took a new piece of 22 gauge green wire and I stripped the end and bent it into an "L" shape. However, I couldn't hold it and solder it. Not having one of those handy gizmos with the alligator clips on the ends, I taped the wire to my workbench light and adjusted the light until the wire ended perfectly on the button. Two free hands to solder... yay!  I used a microbrush to apply a blob of flux on the button. I think this is the key to success. I heated up the iron really good and wiped the tip clean, and then melted some solder on the end. Finally, I moved in to solder and in one pass lasting about a second the flux sizzled, the solder melted, the wire fell into the solder, and I pulled the iron away to let it cool. It was bright and shiny.

I then gave the wire a nudge. Nothing happened. I gave it a gentle pull. Nothing still. I then tugged it a bit, and it stayed fast. It had worked! I was so excited I emailed my friend to tell him the news. I had made a good solder joint. Had I done anything unusual? Not really. I just followed good practice. I can't explain why it worked for me and not others, but I have now soldered 6 turnout frogs and all went fine.

Baby steps....

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