I would like to know, what has been your esperience. I want to avoid as much damage as possible to my plastic ties when I solder my flex track jounts. I have heard that a higher Wattage soldering tool works the best. I have used a 25 Watt soldering iron on my last layout and had considerable melting of the ties with it (likely not heating quickly enough). I am trying to make a purchasing decision. I was wondering whether to go with just higher soldering iron Wattage (40 Watts) or go with a soldering gun (75 Watts). I need to know the advantages of one over the other, including the shape and size of the tip.
Being a newbie, this reply is from information gathered from multiiple other thread discussions.
Yes, a higher wattage solder gun is a good idea when soldering flex track, since it will heat the solder faster. To avoid melting ties, some sort of a heat sink is a good idea. You can use an alligator clamp, or I’ve seen discussed on this forum and also in the Kalmbach track-laying book, that one can use wet tissue paper–seems like this would be a pretty fool-proof method even for those of us who are going to be trying track-laying/soldering for the first time.
Use the big gun for track. The faster it heats, the better. One advantage of the large gun is that it does not cool as much when you first touch the work and thus heats things faster. I use a small pencil iron only for fine wiring.
There is no substitute for practice. The pros will tell you how easy it really is, though some seem to forget the first few months of practice.
The shape of the tip can be filed to put maximum surfice on the track.
I’ve been soldering rail joints for over 20 years and can tell you from experience that a high wattage iron works best.
I use a 100 watt soldering iron myself. Before I solder a rail joint, I place wet cotton balls on the rail on either side of the joint I’m working on. This cools the rail and keeps the ties from melting. It take about 4 - 5 seconds to solder a joint, sometimes less.
I’ll have to disagree with Art here, the bigger guns will give you a lot of heat fast, but that’s what melts ties. I use a 42 Watt iron with a small chisel tip. A smaller iron should work well for you too. The biggest problem in soldering is GET THE METALS TO BE SOLDERED CLEAN. Don’t count on flux or rosin core of solder to clean it for you. Buff the area of the rail and the end of the wire to be soldered clean. I have used both a small wire brush and a typing eraser (the kind you sharpen like a pencil) to do the buffing. The metal should look clean before you start. I use a liquid flux, just a small drop on the joint area, then get a bubble of melted solder on the tip of the iron. Touch the tip with the melted solder to the joint, the flux should vaporize in a second or less (longer and you used too much flux). DON’T breathe these fumes.As soon as you see the solder flow into the joint, remove the iron. When it cools, clean off the flux residue. All types of flux are corrosive, if you don’t believe that, read the MSDS on the one you’re using. It should be a strong mechanical joint with a sort of shiny look to it.
I’ll straddle the range of responses and state that both have part of the truth…that is, they are both right.
Physics- heat loss from the higher energy state to the lower happens, for this purpose, at the 4th power of the difference between them. It is not twice the difference, not squared, but to the 4th power. So, the hotter and more massive the tip, the quicker the colder substance will heat up, and the more heat will be retained by the tip.
Secondly, if the rail material has anything on it other than a pristine non-oxidized and contaminant-free surface, you will need a flux. It doesn’t matter if it is acidic or not, just use it. If you do elect to use the acidic flux, wipe the area with a rag impregnated with a baking soda solution as soon as you are done. The chances are very good that your joint will hold for years.
Better yet, scrub the surface clean with a pencil eraser and wipe it with alcohol. That should get you a nice solid solder joint.
You are going to get at least two answers to the question of which soldering iron to use, high wattage or low wattage.
While either may give good results, the higher wattage iron is best.
I have been soldering for 60 years on electronics, sheet metal and model railroad track.
For track soldering the 100 watt iron with a good sized tip will yield the best results. The larger tip will heat the rail very quickly which will minimize the heat spreading to the ties.
Hit the track and then quickly apply the solder. Then get the iron off the track.
As stated previously use something as a heat sink to prevent tie damage. Wet cotton balls work great for this purpose.
All of these answers are good. However for my preference I use a rechargable soldering iron called “ISO TIP”. It heats up immediately with the press of a button and also includes a handy light to illuminate your job. The tips can be interchanged, but I just leave the pencil tip on as it works both with delicate wiring and track soldering. My trick is I use “plumbing” flux. The kind you buy for soldering copper plumbing. Its thick and gooey and I just place a small glob on the area to solder. I heat that up and then gently apply just a small amount of solder to the rail. I’ve not had a burnt tie yet. No matter what method you choose, it will take practice to master.
BTW, the ISO tip iron is about $45…and the flux just a couple bucks.
I use the 100/140 Weller gun. In addition to cleaning the surfaces to be soldered (I use a wire brush in a moto tool), keep your tip clean and tinned. I have used heat sinks and no heat sinks with good results on code 100 rail. The key is: fast in and out.
Everything alse American Beauty 250 watt Resistance system. Just dial in the punch you need.
Track joints 125 watts and about 2 second per joint, feeders at track 75 watts, again about 2 seconds, feeder wire to the bus 150 watts and about 3 seconds perjoint.
Have not fried a tie since I learned how to use this system.
The real key, to soldering track, is to have a good heavy duty soldering gun (old Weller 150/250 watt) and very small diameter solder (.032). Now this is assuming that you are using new track. If you are not then the rails have to be clean and all dirt needs to be removed.
To make the big soldering gun work is the tip. I replace the stock tip with a piece of #12 copper wire. I use this instead of the regular tips as it is cheaper and I can bend the tip to fit into places the factory tips will not go. Also the tip does not have the large end that will retain the heat. I can get in and out without melting the plastic ties this way. The #12 wire heats faster and hotter than the factory tip does. It also cools faster as it has no large area to retain the heat.
You just need to heat the tip up on the gun and then wet the tip (tinning) with the solder and then just apply the tip to the joint and apply the solder. Once the solder begins to melt into the joint release the trigger of the soldering gun and then remove the tip from the track. This should take all of 5 seconds or so once the tip touches the rail joint.
Now once the solder and joint cool go in and dress up the joint with a file.
It will take some practice to get it right but it can be done.
I have done soldering to lap top circuit boards with an old Weller 150/250 watt. And no I did not destroy the PC board! You just have to know what you are doing with a soldering gun.
I sed to use a Weller 100/140 watt soldering gun, but switched to a Weller 35 watt professional soldering iron with a chisel tip when I got a Fasttracks turnout jig.
The 35 Watt iron has a high tip temp (about 850 degrees), so the rail heats to a temp that melts solder faster than it will with the gun (which heats to just a bit over 700 degrees, I think), even though the gun has a higher wattage. I melt a lot fewer ties with the iron whan with the gun.
The keys to good solder joints with minimum damage to plastic ties:
Clean surfaces. Wipe with alcohol, scrape, file or whatever. The metal to be soldered must be free of dirt, oil and corrosion.
Flux. I use a tiny dab of rosin paste flux. Sometimes the core flux in rosin-core solder turns out to be too little, too late. (Note that when I add flux to a joint I use a toothpick, not a shovel.)
Heat. Whatever the tool, it must be hot enough and massive enough to transfer a lot of heat quickly, and it must be hot enough to melt solder BEFORE touching it to the rail.
Heat sinks. Placing damp paper around the site is one method. Paper clamps on the railhead also work.
Movement, elimination of. If a joint is mechanically tight and held that way during the soldering process it will probably be good. Any movement while the solder is molten will result in a “cold” joint, an invitation to failure. If the solder looks shiny, you’re good. If it looks grayed or “crackle-finished,” reheat.
Speed. With clean, fluxed, well-secured wire-to-rail joints, my pre-heated Weller hand cannon only needs a maximum of two seconds in contact with the railhead and wire to transfer all the heat necessary for a good, solid joint.
Cleanup. Rosin flux residue can be cleaned up using Q-tips and alcohol. Check the railhead for solder, and remove if necessary.
I have wire - to - rail connections (and soldered-rail specialwork) that have been in service since 1980, with no failures, so I think I can say that the above methods work.
Happy soldering
Chuck (who builds specialwork from soldered-together pieces of raw rail)
35 Watt PROFESSIONAL iron with chisel tip is the best way to fly. I use Weller and Ungar when they are on the layout and not the service bench. In a pinch I occasionally use misc. 25 to 40 watt irons. 25 just makes it and anything above 40 is like using a 12 gauge to hunt squirrels when a .22. will do. (I know, that big BOOM is the fun part).
If you need a hundred watts, then something is very wrong - possibly either a low tip temperature, dirty rails or a dirty iron.
Clean material, clean tip properly tinned, and small diameter rosin core solder make a big difference. I heat the joiner on one side of the joint, apply solder and slide the tip to the other side of the joint. Perfect every time in a few seconds. Often I don’t even bother with heat sinks although for non professional solderers the wet cloth method works OK as do metal forceps.
I have used all kinds of irons and guns and the best thing was a really big iron. It heated the rails up really quickly and didn’t melt the ties nearly as easily as the medium and big guns did. Mass is your friend when it comes to soldering. I used to use a hemostat on each side of the joint to keep heat under control. I haven’t even started a layout yet, but have already been soldering up sticks of flex track for the yard, the first part I will build. The big iron died, so I have to use my big gun, not bad, but not nearly as good as the big iron was. I gotta try to find another one.
Karl or anyone… Any tips for tinning the iron tip. It’s still, of all the tasks in soldering, the one I am not very good with. No matter what I do - tinning flux or otherwise - I get a ball of solder on the tip of the iron, not a nice coating all over as when you get a new tip… Any tricks or ideas?
Do NOT dip the tip of the iron in the flux (yes, I have seen some old timers do this).
When the tip reaches temperature to melt solder, wipe it quickly with a wet sponge or cloth to knock off the old solder and flux residue. Use a wire brush if necessary to remove stubborn flux residue.
Quickly touch and remove the solder to the tip and leave only a small bubble of melted solder. Lightly wipe the tip again with the wet sponge or cloth.
The tip should now be a shiny silver color. Also, do this just before you turn off/unplug the iron.
It will probably take you about 3 to 4 times as long to read this as it does to do it. This whole thing is very quick, maybe half a minute at most.