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Why Won’t The Solder “take”?
Soldering is something most in the hobby will need to master. If the solder will not take it is an indication the surfaces are not clean enough, or soldering iron is still not hot enough. The solution is to ensure BOTH surfaces are clean and shiny. Also make sure you have applied a thin coat of flux. The soldering iron needs to be hot enough for the flux to sizzle and boil just prior to applying the solder.
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6 Responses to Why Won’t The Solder “take”?
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And sometimes it just wont. I soldered about 50 connections on a friends 3 rail track one day. All new track, all apparently identical, and in one spot it just was not happening. Cleaned it as the others, used the same flux in the sameish amounts, same wire, no joy. Went on and soldered the rest with no problems. Go figure.
Michael the Crank
If I may expand on your perfectly correct advice, sometimes cleaning will require a solvent like acetone(nail polish remover)or Wax and Grease remover(SuperCheap) sparinly used on a cotton bud prior to flux. This is to remove oil etc. Additionally, whilst the iron may be hot enough to melt the solder, the heat must be passed to the rail before the tinning will occur. Be warned that there is no time for dillydallying since the plastic sleeper will melt if you are on it for too long. Practice on a spare piece of rail is a great idea!!
Maybe a piece about the different types of soldering irons would be of interest?
ie; low voltage 3.3v (scope) good for when additional heat is required
automatic precise temperature control units.great for precise working on decoders ect.
I can not express enough about keeping your solder gun tip clean. A dirty solder tip will not transfer the heat very well and you will half to keep the iron on the track to long causing ties to melt.
To clean the tip, use a small wet sponge and wipe the tip with it after every solder joint. Melt a little solder on the tip and wipe it again. This will make the tip shiny and much more efficient.
A 25W – 50W soldering iron should be more than adequate for soldering up to Code 100 rail. Are you trying to solder to steel rail? It may be that a different flux is required for your task. I find normal resin-cored solder is fine on nickel-silver, copper and brass, but I use Baker’s Soldering Fluid if I need to solder to steel. Hope this helps.
Les
There are many reasons for this. First there needs to be an understanding of what soldering is. Soldering is the process of joining two metals together with a third to create a new one. If it is done correctly the metals are joined together at the molecular level. Soldering is not gluing.
As already stated the surfaces need to clean and free of any containment, and the right amount of heat is required – 450 to 650 degrees F. Clean surfaces with isopropyl alcohol. Use a pink pencil eraser to remove oxidation. Flux is useful but leaves residue behind which has to be cleaned with isopropyl alcohol. It is possible to solder without flux if the components to be soldered are containment free. A lot of electronic manufacturing company’s don’t use flux. Also the size of the tip on the soldering iron matters. The larger the mass to be soldered the larger the iron tip needed and the more heat required. Don’t use a cone shaped tip used for PCBs when tinning wires, soldering wires to lugs or soldering rails. Use a flat tip. Good heat transfer can accomplished using whats called a solder bridge. What you are aiming for is called wetting. Solder joints when done correctly should be smooth and shiny. If they are not shiny they are called cold solder joints and you don’t have metal joined together at the molecular level. Which will lead to failure.
Don’t forget to use a heatsink to protect components from heat damage.