Joe Fugate is absolutely correct in his opinions on NOT using acid flux. As a long time electronics technologist, I have seen electrical kits (stereos and radios) built using acid flux. In about a year, they are only junk. They could not be repaired. Acid flux is only to be used in copper pipe plumbing and even that has been replaced with less corrosive materials.
Modern day rosin flux is just as good as acid as long as it is fresh. One year old rosin flux is next to useless. Paste rosin flux has its uses in soldering feeders to rail but, like ACC, you sometimes need the water thin variety to flow in inaccessible spots.
I didn’t realize rosin paste had a shelf life as I’m still using without problem my fifty year old (probably inherited from my grandfather) tin of Nokorrode. I assume also that the flux core electrical solder I use has a shelf life past a year or is that not correct? Thanks for the heads up. J.R.
Exactly right. While it doesn’t show up much on nickel-silver it will corrode the daylights out of steel rail. Always use non-acid flux. I use a non-spill paste flux from Radio Shack.
Yes, flux core solder has a shelf life as well. Bear in mind, old flux and solder will work, it just takes more heat and time to get good results. I had been using a roll of solder at work for several years and when I finally used it up, I got another spool. What a difference!!
I’m using liquid rosin flux on my turnout construction projects (even though Fast Tracks recommends acid flux) and I find it’s plenty aggressive. Plus I can sleep better at night with no worries that 3 years later the rail’s gonna pop off some turnout ties because of an acid flux bubble under the rail that I couldn’t rinse away.
It could be that Fast Tracks is right and 90% of the time a good scrub of the turnout will remove all the acid. But if reliable turnouts are your goal, the approach used needs to be as dummy-proof as possible so there’s NO CHANCE of something coming back to haunt you, not even just a little bit.
The way my luck goes, somebody like Andy Sperandeo would be attending the op session were the main yard throat turnout failed because some acid flux got trapped under the rail base and slowly ate away at the joint!
Here’s my ongoing step-by-step how-to on building a reliable and great looking turnout using the Central Valley turnout ties and Fast Tracks materials/tools.
The idea is that using the CV turnout ties (with all their marvelous tie plate and spikehead detail) with a lot of Fast Tracks assists (frog and point rail jigs) along with PC ties to anchor the rails down will get you a reliable, excellently detailed turnout in record time (compared to cut-and-fit handlaying). Since the rails are soldered down, the turnout is dimensionally stable and ought to easily give a lifetime of reliable service.
Now if we could just convince Fast Tracks to do a full turnout jig that’s compatible with the CVT ties, I would be in heaven! [swg]
I cannot, for the life of me, imagine why it is recommended for any model railroad use by anybody.
BTW, thanks for the heads-up on rosin flux shelf life. I haven’t really had any problems with my old stuff - but I use a hot, high-capacity soldering tool for all my on-layout soldering.
Chuck (modeling Central Japan in September, 1964 - with lots of soldered joints)
soldering to rail needs LOTS of heat. Whether its old rosin or not, with the rail too cool it will never stick. A REALLY hot iron work better than your average electronics soldering gun.
A HOT iron will get the heat HOT at the SPOT FAST that you HEAT.
I will tend to get a dab of solder on the rail correctly then its easier to kinda sweatsolder the wire on. Get solder on the wire also, then just sweat the 2 together.
HOT heat means the local area you heat will heat fast, and the second you release the heat is carried away fast. Letting the iron sit on the rail and pray it gets hot enough doesnt work, it means the iron isnt HOT enough. Fluxless solder could even work fine as long as the rail is clean, but the flux works to clean the application area.
Never heard of non acid flux having a shelf life. Interesting. I have a tin of non acid paste/gel around here somewhere that is at least 25 years old. I had not noticed any degradation of performance. But NOW, I will not rest well until I get some new, darn it !
I’m wondering why this is even a question. Even as a teenager I was told clearly that rosin core solder was the way to go for electronics and acid core was for pipes. This should be a “no brainer”.
Like Bruce, I’m a long-time electronics technologist and it’s unthinkable to me that anyone would use acid flux solder on electronics. If you’ve learned enough to be soldering electronics, you must have learned to use only rosin core solder. I was once asked to finish installing a PA system in a church. The job had been started by a member of the congregation who knew nothing about electronics and had gotten in over his head. At least he had run the cables, saving me that dirty job. He had used acid core solder and his comment when I expressed horror was, “What’s wrong with that?” I forgave him because the only soldering he had ever done was on plumbing pipes. I cleaned and or replaced what he had done, and fortunately the system didn’t give them any problems.
The reason it’s a question is because Fast Tracks, the makers of the very useful turnout jigs, recommends acid flux when soldering rail to PC ties when using their fixtures. They claim the extra aggressive nature of acid flux makes the soldering job easier, and that if you wash up the turnout well after you’re done, you shouldn’t have a problem.
Basically, it’s true, acid flux is more aggressive than rosin flux. And it’s also true washing the finished turnout well in soap and water will clean all the visible acid flux off the turnout. My only concern is getting a bubble or residue of acid flux caught under the base of the rail. With acid flux in some hidden location you can’t wash, it will continue to eat away at the joint and eventually cause the joint to fail years later – this is even true on copper pipes, where acid flux is most commonly used.
In my experience, using acid flux is just plain unnecessary and adds another way your trackwork can eventually fail. Liquid rosin flux is plenty aggressive for soldering rail to PC ties and if a bubble of rosin flux ever does get trapped under the rail base (probably unlikely, but better safe than sorry) then the rosin will be a non-acid when cold and my trackwork won’t ever fail because of some hidden acid eating its way through things.
IMO, you might be okay 90% of the time, but it’s the other 10% that concerns me, and not all modelers are soldering experts, so why ask for trouble when it’s simply unnecessary? With acid flux, you are hoping the modeler does a thorough job of cleaning the turnout before placing it on the layout. With rosin flux, if the modeler doesn’t clean the turnout properly, you’re still covered.