This may sound very primative to some but I just saw a couple of videos on YT and one siad not to Flux thought it was the worst thing you can do , yet others slab it on. So do you or don’t you and why?
Thanks all,
sorry , it is in ref to soldering tarck, feeders, joiners… thanks
I use it on most solder joints (joiners, feeders, decoder hard-wiring). I’ve heard all the arguments from those claiming there’s plenty in rosin core electrical solder, and how using extra flux is a sign you’re a rank amateur. They can shove it. I notice the difference when working on feeders and especially joiners. Heat transfer and solder flow through the entire joint is enhanced when I’m not depending entirely on the flux to flow from the solder itself.
I do avoid acid flux for any soldering on the layout.
I no longer bother with flux.
I fail to see any real advantage.
Rich
It would highly be depending on what you are using the,‘‘Flux’’ for,I would not recommend,using it on ‘‘Printed Circuit Boards’’,for soldering feeders to rail is OK,I simply use 60-40,rosin core solder,about 1/16in dia,rough the rail a bit,then solder away…Maybe it was another of the hazards,issue…
Cheers,
Frank
When I hear about using flux it’s almost in reference to soldering. Yes, I do use paste flux in my soldering work. I put a little on the surface that I’ll be soldering to and I’ll dip the end of the wire into it then solder the wire to the aforementioned surface. In the case of wires that are going to be twisted together then soldered I’ll put some flux on each wire then twist them together and solder them. The solder will follow the flux into the twisted ends so there’s solder inside the bundle as well as on the outside. I learned the importance early on of using rosin soldering flux. On the first layout I soldered rail joints on I thought what the heck, flux is flux and soldered the joints using an acid base flux meant for plumbing work. It worked OK for a little while then after a few weeks the rail ends and joiners turned a dark brown the they turned black and began to disintegrate. It wasn’t long before the soldered joints were becoming corroding gaps! I had to replace each and every section of track and this time I used electronics grade rosin flux and didn’t have any problem. Now I’ve seen a lot about flux making a mess and running and puddling when heat is applied to it and yes it will do that especially if you use too much. With flux a dab will do ya. A little bit will be fine. For rail joints I usually brush a thin layer of flux on the outer edges of the rails and in the joiners. When heat is applied to the joint the flux draws the solder into the joint and welds it together securely.
If everything you solder is pre-tinned (like some soldering lugs on toggle switches, most resistor and capacitor leads, pre-tinned wire and the silver traces on PC boards) you can get away without flux.
OTOH, having extra ROSIN flux won’t hurt anything, and it just might make the difference between a barely adequate joint and a rock-solid, last for the ages joint.
Back in 1980 I built a module, all track hand laid. I used my usual methods, including a dab of paste flux on every joint. Some of those joints (rail drops, specialwork) still have flux residue on them - and in 32+ years of almost continuous use, the last ten years under VERY adverse conditions, not a single joint on that module has failed.
My bottom line? The extra second spent assuring that the joint is properly fluxed is worth it, and flux doesn’t cost much either.
Chuck (Modeling Central Japan in September, 1964)
Never really saw the point of the stuff myself. All my track is soldered as is all the drop feeds to my buss. I’ve scratch-built dozens of brass signal towers and even a very elaborate facility in my engine terminal all out of brass and have never used flux on any of it. If the metal is CLEAN, there really should be no need for it.
My opinion …
Mark.
Rosin is a flux. Flux is an agent that cleans the metal at temperature to allow a smooth flow and adhesion to surfaces by chemically cutting into the oxide layer on the objects your are soldering together. A rosin-core solder is all you need.
If you have ever sweat a copper pipe, you will understand the role of flux. There are a variety of them out there for plumbing purposes. Some are very acidic and you can see them just brighten up that copper pipe as soon as the torch starts heating up the joint. Electrical solder is doing the same thing. If you didn’t have a flux of some kind, your solder would ball up and not stick to anything except itself.
An extra tub of flux isn’t required unless your solder is solid-core.
If you are using a real good rosin core solder, then you don’t need to use flux. I use Radio Shack 60/40 rosin core solder and it flows very well. One thing to look at with the solder is the color. If the solder is grayish flat silver color it usually doesn’t take the heat well and flows very poorly. The solder that has a shiny silver luster flows and takes the heat very well and is a lot easier to work with.
The problem with rosin core solder is that in time it dries out and is not as effective. Or there is not enough.
By adding a little flux first, it really enhances the process. When the iron hits it, it immediately goes to work, then touch the solder to the work and it wicks into the joint.
Well, I’m not sure what flux has to do with soldering, but it’s certainly a useful product:
Oh, yeah, and I always use that other stuff when soldering. [swg] [(-D]
Wayne
Interesting discussion. There was a letter to the editor in this years August issue where the writer discussed flux. To quote him, “Flux’s only purpose is to prevent the slight oxidation of the surfaces as they’re heated by the soldering iron. That surface oxidation from heating cannot be prevented, so flux removes that and thus prepares a truly “clean” surface that’s ready to accept flowing molten solder. Therefore, adding more flux is actually quite useless.”
He says that he was an instructor at the US Army’s soldering school at the Redstone Arsenal in Alabama, so I would presume that he has some knowledge of the subject.
I’m not a soldering expert, but I play one in my train room [:D]
I have no doubt the letter writer is right in what flux’s true purpose is, and that technically it’s not required, but… With all due respect to retired Army rocket scientist electronics guy, I have to disagree that adding more flux is useless. What he’s saying makes sense, but through trial and error, I have found that adding some paste flux (in addition to what’s already in the solder itself) makes the task noticeably easier and less frustrating for me. Maybe if I were a former instructor at a soldering school I’d be good enough to not need flux, but I find it keeps my stress level down in the train room, so I use it. That’s just how I roll.
PS - the “guy” remark was meant as a good-natured friendly “rib”, not a denigrating slam. I’m an active duty Navy guy myself. I actually had to take a contracting class at Redstone Arsenal a few years ago. Decent place, but I had an awful case of food poisoning the first couple of days. Other than that, it was a nice little boondoggle [:D]
For longevity and uniformity of the solder joint, I would consider flux vital. The stuff’s cheap as dirt anyway; why make soldering any more difficult than it needs to be?
Check this out:
http://www.youtube.com/watch?v=inHzaJIE7-4
I worked with one of these monsters for close to a decade; that foamy bath you see at the beginning is flux (gallons of it). Electronics manufacturers love to cut costs as much as any non-going-bankrupt business; if they could get a reliable joint without flux, they’d be doing so.
Stu
I remember what it was like to solder with out brushing flux on. Yes, some solder is supposed to have flux in it but after i started using brush on flux, I"d never go back. This question doesnt really need to be asked. Just use it!
I use flux. Period![:D]
Dave
Just want to thank all for input and logic.
All I know is that last week, as part of an Athearn tune-up, I tried soldering a wire to the top motor clip. All I could get was a wire with a glob of solder on it, and no adherence to the clip. Went out and picked up some flux, which set me back all of two dollars, and wiped a small dab on the clip. When I re-touched the iron, WHAM! Instant rock-strong connection.
That’s why there are two distinct schools of thought on this issue.
When I solder wires to decoder leads, I never even think flux. I place a drop of solder to form the connection and I am done.
Rich
If you would have roughed up the surface of the clip,before trying to solder,you would have gotten better results,the flux cleaned the surface,that you were soldering to…
Cheers,
Frank