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Soldering wires to a sound decoder

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  • Member since
    December 2004
  • From: Pa.
  • 3,361 posts
Posted by DigitalGriffin on Monday, April 30, 2007 10:19 AM

What I like to do is

1)  tin the connecting wire first.  (Melt solder on the wire...this makes it stiff)

2)  Stick the wire through the hole on the solder pad

3)  Heat the wire (not the pad) with 15->30 watt solder pencil tip gun. 

4)  The tin on the solder will melt and downward and fill the solder pad hole making a secure connection.

Easy as pie.

15 installations and counting....

If the decoder doesn't have holes then apply solder resin using a small brush.  Then apply steps 3->4 above.

Don - Specializing in layout DC->DCC conversions

Modeling C&O transition era and steel industries There's Nothing Like Big Steam!

  • Member since
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  • From: Finger Lakes
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Posted by howmus on Monday, April 30, 2007 10:05 AM
 Vail and Southwestern RR wrote:

I'll respectfully and politely disagree.  It is important to get the pad and the wire hot.  A drop of solder on the iron may flow onto the wire, but you're not going to know that you get the pad hot enough to get a good bond.  That's the reason to heat the surface, and then let the solder flow to it.  The drop method probably works most of the time, but I don't hink it is the most reliable method.  With a properly small, tinned iron, small enough solder, and clean surfaces, it isn't goign to take long, and nothing is going to get too hot.

You are using the "textbook" method of electrical soldering.  Yes it works very well and there is absolutely nothing wrong with it.  BTW about half the time, depending on the size of the joint and what is needed to do a good job, I also add a very small amount of solder to the joint as soon as the solder flows.  If the solder flows to the pad (That is actually where I place the iron, as close to the wire as possible) it is hot enough. The reason I use a small drop of solder on a well tinned iron is to increase the surface area of the heat transfer.  This way the area to be soldered heats much faster and does not have time to spread the heat to things you don't want melted.  Often the joint does not need any more solder.  Many people use way too much solder which can cause problems as well.

I originally learned to do electrical soldering while working as a summer hire at at phone company.  Part of my time was spent soldering wires to a mainframe (back in the late 60's).  There we used 120 watt monster irons to do the job.  You wrapped the 22 or 24 guage wire around a post hit the backside of the job with the almost red hot iron, touched a bit of solder to the other side and things melted quickly.  You didn't want to touch anything nearby for a minute or so.......  After I opened a recording and live sound business, I found that I often had some extremely small wires that had stressed and broken and often found cold solder joints from the factory on equipment.  I usually took the equipment to a music store locally where they also repaired electronics.  On one occasion I had the chance to see their repair guru work on a couple of jobs.  He is a third generation TV repairman who closed his families business in the 1980s after it became cheaper to buy new than repair TVs.  He never used more than a 10w iron for the repairs and his work never failed.  The method I use, I learned from him (he took about 15 minutes to show me his technique and explain why he does it that way).  Since that time I no longer have 1. cold solder joints. 2. melted ties, or other similar problems.

Here is a close up of some of my work:

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To each their own.  My honest advise is try several different methods and see which one works best for you. 

 

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

We'll get there sooner or later! 

  • Member since
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  • From: Vail, AZ
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Posted by Vail and Southwestern RR on Sunday, April 29, 2007 10:55 PM

 howmus wrote:
There are actually several possible ways to get the job done (I'm waiting for the guy that only uses a 250 to 340 watt electric gun and says that anyone who doesn't do it his way with several heat sinks in line is a nut case......). While I most often agree with everything Randy says, this time my own experience and training prefers David's way of doing it ( notice I said "prefers").  I always use a small drop of solder on the iron and place the iron at the joint.  The solder will flow to the joint immediately. Get out right then.  The whole thing will be done in about a second.  Don't wiggle the wire to see if it has set!  That is what usually causes the "Cold Soldering Joint".  Not a good thing.  Get in, make the solder, and get out.  Let it cool.  This is actually a very easy task. 

I'll respectfully and politely disagree.  It is important to get the pad and the wire hot.  A drop of solder on the iron may flow onto the wire, but you're not going to know that you get the pad hot enough to get a good bond.  That's the reason to heat the surface, and then let the solder flow to it.  The drop method probably works most of the time, but I don't hink it is the most reliable method.  With a properly small, tinned iron, small enough solder, and clean surfaces, it isn't goign to take long, and nothing is going to get too hot.

 

Jeff But it's a dry heat!

  • Member since
    December 2004
  • From: Finger Lakes
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Posted by howmus on Sunday, April 29, 2007 10:18 PM
There are actually several possible ways to get the job done (I'm waiting for the guy that only uses a 250 to 340 watt electric gun and says that anyone who doesn't do it his way with several heat sinks in line is a nut case......). While I most often agree with everything Randy says, this time my own experience and training prefers David's way of doing it ( notice I said "prefers").  I always use a small drop of solder on the iron and place the iron at the joint.  The solder will flow to the joint immediately. Get out right then.  The whole thing will be done in about a second.  Don't wiggle the wire to see if it has set!  That is what usually causes the "Cold Soldering Joint".  Not a good thing.  Get in, make the solder, and get out.  Let it cool.  This is actually a very easy task. 

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

We'll get there sooner or later! 

  • Member since
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  • From: Reading, PA
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Posted by rrinker on Sunday, April 29, 2007 9:34 PM

 Do you clean it? I wipe the tip on a wet sponge after every soldered conenction. If the tip no longer stays shiny after cleaning it's time to replace it. Any sort of abrasive will quickly remove the plating ont he tip and it will NEVER stay clean. Using the tip to strip the insualtion off the decoder wires, or touching it to heat shrink tubing while shrinking it, will also contaminate the tip and make it not transfer heat properly.

 

                                        --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
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  • From: Colorful Colorado
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Posted by Texas Zepher on Sunday, April 29, 2007 5:10 PM
 davidmbedard wrote:
I ... have to tin the tip about every 20 seconds.
Sounds like the iron needs a new tip.  One should not have to do this.
  • Member since
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Posted by rrinker on Sunday, April 29, 2007 11:30 AM

 Yes you should tin the soldering iron tip but you don't have to do this ever time you heat up the iron, and when soldering the joint you NEVER apply the solder to the iron, you use the iron to heat the joint anda pply the solder to the joint.

 

                       --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
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  • From: Tacoma, WA
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Posted by ShadowNix on Saturday, April 28, 2007 9:51 PM
 davidmbedard wrote:
 rrinker wrote:

 I have a 15 watt iron I use for soldering decoders and associated wiring - PLENTY big. Solding wires to the tabs there for the track pickups, motor, and lights is pretty easy. Strip the wire, twist the ends (since the wire is usually stranded - don;t want stray strands that could short somewhere sticking out, and apply some solder to the wire (called tinning). Stick the wire through the hole in the proper pad, pinch it over so it's physically snug, apply heat and solder. It should take only a second to heat and melt the solder. Do NOT apply the solder to the iron.

 

                                                --Randy

Actually, all soldering books and guides and everyone that I know that solders acutally add some solder to the iron.  The reason is that the solder on the iron acts as a heat conductor.  Without it, you will run the chance of heating up the surrounding area.  Solder on the tip (called tinning the tip) will allow for the most efficient heat transfer to the joint.

Clean the tip between uses (the tip will oxidate in about 20 seconds.....hence becoming a poor heat conductor)

Try not to apply the iron (heat) directly to the joint, but rather just off to the side of it.

David 

Sign - Ditto [#ditto] You have to tin the soldering iron for good (fast) transmission of the heat... David is right on.

 Brian

"That which doesn't kill you makes you stronger!"
  • Member since
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  • From: Reading, PA
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Posted by rrinker on Saturday, April 28, 2007 4:25 PM

 I have a 15 watt iron I use for soldering decoders and associated wiring - PLENTY big. Solding wires to the tabs there for the track pickups, motor, and lights is pretty easy. Strip the wire, twist the ends (since the wire is usually stranded - don;t want stray strands that could short somewhere sticking out, and apply some solder to the wire (called tinning). Stick the wire through the hole in the proper pad, pinch it over so it's physically snug, apply heat and solder. It should take only a second to heat and melt the solder. Do NOT apply the solder to the iron.

 

                                                --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    April 2003
  • 305,205 posts
Posted by Anonymous on Saturday, April 28, 2007 2:04 PM
Those end tabs are a piece of cake to solder. However, be very careful with those two little holes where the speaker wires go, and don't let any solder overlap the edge of the holes, and short out to some other connection nearby. Check both sides of the decoder, to see what is there, before soldering the speaker connections. There are some components very close to the speaker holes on one side of the decoder.
  • Member since
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Posted by CSX_road_slug on Saturday, April 28, 2007 1:16 PM

Thanx a lot for the replies, guys!  I guess the thing I need to do is get a precision iron, something smaller than my 80-watt tool.

 

-Ken in Maryland  (B&O modeler, former CSX modeler)

  • Member since
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  • From: Colorful Colorado
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Posted by Texas Zepher on Saturday, April 28, 2007 12:23 PM

 CSX_road_slug wrote:
I'm getting ready to solder the necessary wires to a Soundtrax decoder. ...There doesn't appear to be much room for placing a heat sink. Is it critically important for me to use one of those?
I have never used a heat sink for soldering.  Never.  Heat sinks are umm how does one say this nicely, a crutch for improper soldering practice.   Heat the board and the wire simultaniously and quckly.  Hit the joint with the solder.  Remove the heat and then blow to cool, the rest of the components won't even know a solder was done.

But, how is soldering going to reduce the sensitivity to dirty track?  The two aren't related.  Just use the cute little plastic connector caps designed for the unit.  I have never had trouble with those unless they were put on wrong. 

  • Member since
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  • From: Sierra Vista, Arizona
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Posted by cacole on Saturday, April 28, 2007 10:08 AM

A heat sink is not required, but a controlled temperature soldering tool or low wattage soldering iron with a very small tip, and rosin core electronics solder is required.  Apply heat only long enough to melt the solder.

 

  • Member since
    June 2006
  • From: Baltimore, MD
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Soldering wires to a sound decoder
Posted by CSX_road_slug on Saturday, April 28, 2007 9:14 AM

I'm getting ready to solder the necessary wires to a Soundtrax decoder.  I've heard too many horror stories about these guys being hyper-sensitive to dirty track, so even if this is supposed to be a plugNplay, I want to eliminate this potential weak point.

There doesn't appear to be much room for placing a heat sink. Is it critically important for me to use one of those?  And if that's the case, can you offer some pointers?

T-I-A ...

-Ken in Maryland  (B&O modeler, former CSX modeler)

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