Recently I have had two engines that would stutter and/or stall when going through a switch. I check the switches and found nothing wrong. I took the body off the engine and got it to stall in the middle of a switch. I checked for power with a volt meter and found that power was not getting to the decoder but was being picked up by the wheels. In between the wheels and the decoder was a solder connection. Wiggling the solder joint and the engine started moving. Although the solder joint looked fine, it was not making a good electrcal connection. A cold solder joint. The fix is easy enough. Just touch the joint with a hot soldering iron.
The truck movement and the 'bumps' going through switches was enough to jiggle the connection.
But I was wondering how this happened. I'm not perfect but I have been soldering connections and printed circut boards for a long time. Then it dawned on me what might have happened. For years I used a soldering iron that you plug in and use it when it got hot. A couple of months ago I decided to go high tech and get an adjustable temp soldering iron. I have been soldering with the temp set just high enough to melt the solder. I guess it was not hot enough to make a good joint.
Lesson learned. Go back to the trusty soldering iron that was always hot enough or turn the high tech iron all the way up.
South Penn,
A few questions for you:
Overheating the solder is just as bad as underheating it. If overheated, the plating on the soldering tip will wear off more quickly and you won't be able to transfer the heat to the part(s) - no matter how high you crank your iron.
A clean and shiny solder joint is what you should strive for. A small amount of flux - in addition to the flux found in flux-core solder - will aid in transferring the heat evenly so that you can achieve that shiny and smooth solder joint. A wide chisel-type tip also helps heat the part more quickly and evenly; handy for soldering things like track feeders to track.
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
soldering is intended to make a chemical bond between the materials, not just physical contact. It's not enough to make a nice looking shiny blob of solder around a wire. You need to make sure the solder has attached to both pieces being soldered together.
The best way to do this is make sure both pieces are tinned before soldering.
i've have some salvaged components. The leads seem reluctant to be tinned and I need to be patient whe soldering.
greg - Philadelphia & Reading / Reading
Well, you don't want to turn it all the way up, either. Mine is an older model without a digital readout, but aboout halfway works for most electronic work, like circuit boards and fine decoder wire. About 3/4 when soldering larger objects like attaching wires to rails or soldering rail joiners. About 3/4 also worked well when building Fast Tracks turnouts. All the way at the minimum shrinks heat shrink without melting it all over the tip.
The tip must be clean to get optimal heat transfer - a lower power iron with a clean tip will heat the joint faster than a higher wattage iron with a dull tip. I actually rarely tin connections but for things like feeder wires or rail joiners I do apply some gel flux - for rail joiners carefully to the bottom and outside of the joiner before slipping it on, so that the solder wicks mostly to the outside where it can't interfere with the wheel flanges. Done right, you can apply the iron to the outside of the joint and the solder to the inside and it will wick under the joiner and over to the outside edge. As soon as solder appears on the inside, you have enough - the outside is filled in, any gaps underneath are filled, and there is just a slight fillet along the inside to make a strong joint without sticking up into the flange area.
I'm also a heretic in the sense that I don't use heat sinks when soldering rails. The only ties I melt are when I do something stupid and actually touch the iron to the plastic, and no amount of heat sinks or track gauges laid across the rails can stop that. The key is the clean tip, proper temperature, and the flux. I also almost always use fine solder - .016 or .015, unless there is a LARGE connection to be made - such as feeders to bus, where I use more ordinary .032 solder with a 150 watt gun - my little 40 watts soldering station can barely warm #12 stranded bus wire.
I also refuse to use the lead-free junk, the melting points are all different (most need more heat). When they first started using lead-free solder in production, many components weren't designed to take the higher heat and were subject to stresses they didn;t get with lower temperature leaded solder processes, that's why a number of years back there were a LOT of unreliable electronics. Things are more adjusted now. It's like how you can tell what year each car maker switched to the water based paints, the year of the switch and maybe the year after all have peeling paint if they are still on the road. New materials require process adjustments andit takes a while to get the bugs worked out. 63/37 all the way - it has a lower melting point than 60/40 and better wetting of the joint due to the higher tin content. And a a eutectic system, it goes directly from frozen to liquid and back, with no in-between plasticky state. Less chance of a poor joint because a component lead or a wire moved before the solder froze. Downside is 63/37 costs more because tin is more expensive than lead, but also consider I bought a 1 pound spool about 8 years ago and built a complete layout plus several circuit boards and still have the bulk of it left, it's certainly not a budget breaker.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I have used a Weller WLC100 station for some years. Digital read out.
Started soldering in 1954 with huge Weller soldering gun. What a diference today.
Fifty percent heat and conical tip for PC boards. Wedge tip and seventy five percent heat for track feeders. Little rosin flux and Cardas quad eutectic silver solder with rosin core. Tips are plated.
Did some feeders on a Bachmann 44 tonner few years ago.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.