It's not that I made up my mind or anything, but I simply read the manufacturer sheet data, what the product is suitable for, and I don't see any incompatibility for electronics, from my ignorance in flux chemistry and advanced hardcore flux knowledge. Then I read it's suitable for uses in tin, copper, silver... and that's electronics. I mean, it's not an unknown chinese flux brand, it's made in the USA, it's flux, if there were some heavy reason for not to use it in electronics, I guess they would have put an advertisement there in the bottle. Or, they could have simply said "regular plumbing flux for pipes", which kind of tells you it's a very specific flux.

Some said that acidic is not recommended, and I read "meets industry standard ASTM B813 and contains no zinc chloride to reduce corrosion concerns, non-acid, non-toxic, and lead-free to eliminate safety concerns". So help me understand why this is not for electronics, if that's the case. I'm simply asking why.

Thank you

 

You have to consider at least 3 things i a flux:

1) Will it work for soldering the metals of interest?
2) Will it unnecessarily harm the tip of my soldering iron? While plumbing and sheet metal can be done with a large soldering iron, one often uses a torch, so wear and tear on the iron doesn't matter that much. For hand soldering electronics, one almost exclusively uses a soldering iron and wear and tear matter. See the link I gave above (post #21 ).
3) Are there long term adverse effects? That is where "acidic" fluxes (meaning fluxes with chloride in the name*) are a problem. A little OT chemistry -- hydrochloric acid and sulfuric acid are both strong acids, but they are not interchangeable. Your lead acid battery uses sulfuric acid. "Acidic" soldering fluxes use salts of hydrochloric acid. The corrosive properties are very different. Copper (II) sulfate and Ferric sulfate do not corrode stainless steel very rapidly. Copper (II) chloride and ferric chloride do. Only a few seconds exposure is enough to see the effect. As an extreme example of the effect of chloride on corrosiveness, gold is stable in sulfuric acid and nitric acid. Add chloride to nitric acid and it corrodes gold to gold chloride and dissolves (see: aqua regia).

Back on topic: For electronics, one tends to avoid chlorides. Chlorides are a member of the "halogen" group of elements. You will often see things labeled "halogen free," which is important for other reasons too.

So the bottom line is that your acidic fluxes will allow you to solder, but what you make will suffer corrosion.

John

*A major component of rosin fluxes as abietic acid. It does not share the corrosive properties of chlorides. Hence, "acid fluxes" generally refer to chloride-containing fluxes.

 

Thank you, but in the specs fo the LaCo it says "non-acidic". And your bottom line says "your acidic fluxes". Am I missing something?

I've just read:
"Ammonium chloride is used as a flux in preparing metals to be tin coated, galvanized or soldered. It works as a flux by cleaning the surface of workpieces by reacting with the metal oxides at the surface to form a volatile metal chloride. For that purpose, it is sold in blocks at hardware stores for use in cleaning the tip of a soldering iron, and it can also be included in solder as flux"

Ethanolamine chloride:
"Ethanolamine is used as feedstock in the production of detergents, emulsifiers, polishes, pharmaceuticals, corrosion inhibitors, and chemical intermediates"

Anyway, what kind of flux would you guys recommend for electronics?
I've read some people prefer "almost liquid" flux, specially for SMD, but since I want it also for batteries, cables and that kind of stuff, I'd rather prefer a paste that you can work with in tiny areas, think of the positive of a battery.

 

Not trying to "argue", I'm simply pointing out that the manufacturer says you can use it for those purposes/materials. Doesn't all of this "All lead-free and common soft solders, Copper, Brass, Galvanized iron, Lead, Zinc, Tin, Silver, Nickel, Mild steel, Terne plate, Malleable iron" include whatever you find in electronics, mainly copper and tin?
I guess they put materials, not the profession itself. Notice how they didn't put use for electronics, just like they didn't put plumbing, or piping. It's because they are included when they say: copper and lead, and also all the other things...

So, hahaha, I guess it's perfectly fine for electronics use, right? Anybody see something bad?

Several people have already answered your question. They see something bad.

The description explicitly mentions plumbing, states compliance with plumbing regulations. And as important, does NOT mention electronics. IMHO any reasonable person would find enough red flags and would NOT use it for electronics.

If you decide to use it on electronics, what’s the risk you’re assuming that your soldered joints won’t fail in six months? A year? Longer? I expect my projects to last for 5-10 years. What failure rate is acceptable to you?

 

Several people have already answered your question. They see something bad.

The description explicitly mentions plumbing, states compliance with plumbing regulations. And as important, does NOT mention electronics. IMHO any reasonable person would find enough red flags and would NOT use it for electronics.

If you decide to use it on electronics, what’s the risk you’re assuming that your soldered joints won’t fail in six months? A year? Longer? I expect my projects to last for 5-10 years. What failure rate is acceptable to you?

That's why I asked this:

Anyway, what kind of flux would you guys recommend for electronics?
I've read some people prefer "almost liquid" flux, specially for SMD, but since I want it also for batteries, cables and that kind of stuff, I'd rather prefer a paste that you can work with in tiny areas, think of the positive of a battery.

I'm not convinced yet, basically because I see you call my flux acidic, and then in the label it says non-acidic, you say it will corrode, and I see one of the ingredients is anti-corrosive, and it's also in the label that prevents corrosion.

This is quite simple to explain. I was expecting a "that's a totally fine flux" answer, and I get an opposite reply. That's alright, but then the "arguments" or things you say contradict what the label says and what the ingredient application says. There's a contradiction, and that's where I lost it. As simple as that. I don't normally blindly believe what I read, I must understand it first, if I can, and if I can't, I try to contrast the ideas to check if there are contradictions.

 

Thank you, but in the specs fo the LaCo it says "non-acidic". And your bottom line says "your acidic fluxes". Am I missing something?

I've just read:
"Ammonium chloride is used as a flux in preparing metals to be tin coated, galvanized or soldered. It works as a flux by cleaning the surface of workpieces by reacting with the metal oxides at the surface to form a volatile metal chloride. For that purpose, it is sold in blocks at hardware stores for use in cleaning the tip of a soldering iron, and it can also be included in solder as flux"

Ethanolamine chloride:
"Ethanolamine is used as feedstock in the production of detergents, emulsifiers, polishes, pharmaceuticals, corrosion inhibitors, and chemical intermediates"

Anyway, what kind of flux would you guys recommend for electronics?
I've read some people prefer "almost liquid" flux, specially for SMD, but since I want it also for batteries, cables and that kind of stuff, I'd rather prefer a paste that you can work with in tiny areas, think of the positive of a battery.

Addendum: non-acidic in this context does not mean not acidic. In general use, the form of some acids are considered “non-acidic”. But those acids are anathema to an electronics environment.

IMHO, the the data sheet doesn’t EXPLICITLY state that use in recommended for electronics. In the absence of that description, there is NO way I’d use it on any of my projects.

Do you put premium gas into your car? Some people do unnecessarily even though the pump states that it’s only for cars designed for it. But, my car runs on it, and it’s PREMIUM gas. So I ignore the fact that it’s not designed for my car and eventually damage my engine.

This fable also apply to your flux...

 

I'm not convinced yet, basically because I see you call my flux acidic, and then in the label it says non-acidic, you say it will corrode, and I see one of the ingredients is anti-corrosive, and it's also in the label that prevents corrosion.

I explained above that when applied to a flux, "acidic" generally applies to having chloride (or similar). Technically, abietic acid in rosin flux is "acidic," but as a famous American once said, "It all depends on what you mean by acidic" (paraphrased for the occasion).

Now, when you take a weak acid and form a salt with a strong base, those are called "basic salts." Examples: sodium borate, sodium carbonate. On the other hand, a strong acid with a weaker base form an "acidic" salt. Ethanolamine is a weak base, and hydrochloric acid is a strong acid. Thus, its salt is called an acidic salt as well as for the reason just immediately given. Ammonia and HCl also form an acidic salt (ammonium chloride), just just as important, it disproportionates into HCl and ammonia, particularly at soldering temperature. The ammonia tends to evaporate easily and doesn't corrode metals as badly as HCl does. If you want a good demonstration of how disproportionation works, get some ammonium carbonate and inhale deeply.

The acidic or basic nature of those salts in water can be calculated from the dissociation constants of the salt, acid, and base involved, but that is beyond this discussion. Clearly, one can add a slight excess of base to make the mixture near pH7 and call it non-acidic, but that doesn't change the fact that it is chloride based.

This is quite simple to explain. I was expecting a "that's a totally fine flux" answer, and I get an opposite reply.

Happens all the time. Don't ask the question, if you don't want the answer. As for what the label says, "all purpose" and "general purpose" probably don't mean what you think they mean. That is, a "general purpose" athlete would probably make a lousy goalie on your national team. Those terms generally mean just mediocre and nothing better.

No one here is saying that the flux you bought will not enable you to make solder joints. What everyone here has said is that those joints may be prone to corrosion and failure in the future. Plus, your soldering iron tip will wear out more quickly.

 

Thanks for the explanation. OK, then it's obvious, if what you say is true, why I was confused: non-acidic things that are actually acidic, general soldering uses that are not really general at all... This is all very bad explained and full of confusion. By all means, there should be a clear label indication that states "this flux is for general plumbing and piping soldering, not optimal for electronics". That's what a professional company does when they know these products can lead to bad decisions, which certainly lead to.

About not asking a question, that's false. You, me and everyone, when we ask something that is kind of unknown to us but it's in a field we are involved, really have some idea about what the answer should be. I'm being honest, I expected a "yes, totally fine" answer, but that doesn't mean at all that I can't change my mind, if I see that what I was thinking is clearly wrong. It is not about "I don't like the answer", but "I don't like this loose answer that is contradicting what I read in data sheet and reviews.

Now, the real question: then what kind of flux do you recommend me? Something that is not liquid because I think that would be really messy and hard to work with. From Amazon if possible?

 

I think this guy is another one of Gerry's students. And I thought I rode the shortbus in learning this stuff. I'm a Rhodes scholar and don't know it.

 

What? Is that some kind of joke? Because I didn't get it. I was asking now for flux recommendations.

 

Thanks for the explanation. OK, then it's obvious, if what you say is true, why I was confused: non-acidic things that are actually acidic, general soldering uses that are not really general at all... This is all very bad explained and full of confusion. By all means, there should be a clear label indication that states "this flux is for general plumbing and piping soldering, not optimal for electronics". That's what a professional company does when they know these products can lead to bad decisions, which certainly lead to.

About not asking a question, that's false. You, me and everyone, when we ask something that is kind of unknown to us but it's in a field we are involved, really have some idea about what the answer should be. I'm being honest, I expected a "yes, totally fine" answer, but that doesn't mean at all that I can't change my mind, if I see that what I was thinking is clearly wrong. It is not about "I don't like the answer", but "I don't like this loose answer that is contradicting what I read in data sheet and reviews.

Now, the real question: then what kind of flux do you recommend me? Something that is not liquid because I think that would be really messy and hard to work with. From Amazon if possible?

I worked in an assembly shop, they used water soluble flux, after soldering just take your board fill the sink with water, dishwasher detergent, wash with a brush and use a hair dryer to dry the board. For surface mount chips, there is a trick you can do with your soldering iron and a broad slightly flatten tip, after you've secured the chip on at least 2 corners opposite one another, you load the tip with solder, non rosin, don't remember the percentages of metal alloy, flux the component and float the solder across the pins holding the board on a slight angle so the remaining solder flows away from the pins back to the tip, I use to float 128 pin processors in about or less than a minute. I did it as well as a machine, having a light board helps in placing the processor properly.

kv

 

I use Kester SP-44 mildly activated rosin flux and have a lifetime supply. Hard to find on Amazon, but this seems similar: https://www.amazon.com/MG-Chemicals...nt=&hvlocphy=&hvtargid=pla-308498472160&psc=1

 

Thanks! I might buy that one. I just read in the comments that the residue is conductive? That seems quite problematic. They also say it's quite messy :/

 

All about Flux and Solder https://www.kester.com/

 

I use Kester SP-44 mildly activated rosin flux and have a lifetime supply. Hard to find on Amazon, but this seems similar: https://www.amazon.com/MG-Chemicals...nt=&hvlocphy=&hvtargid=pla-308498472160&psc=1

I have MG liquid RA flux, it's good.

 

I have MG liquid RA flux, it's good.

Well, I tried again, and I'm surprised:
First of all, I usually solder with a Temp of about 250-300ºC, and when I read you soldered at 350ºC I was a little confused. I read that you have to solder with the minimum required temp, of course to work comfortably, but that's that. So, I guess that was my first mistake, that I didn't put enough heat on the positive. Mainly because I don't want to damage the battery or have an accident. I'm "really" scared of touching a battery with a 300ºC object, specially if it's in front of my hands/face.

Anyway, I tried your method and, VOILA!, I've been totally able to solder the AA battery, here the results:


So, as you can see, rock solid, amazing. I put some flux to fully cover the area, tinned the iron tip, put then the iron tip on the battery, all covered in flux, and then I introduced the solder wire into the mix. Magic, it stuck so well, now it's part of the battery itself, hahaha. I am not sure this was all flux's merit, I'm really thinking that it was simply because I had set my soldering iron to 300ºC instead of 350ºC. Or may be it's both, I don't know.

Now, the interesting part. That battery was an AA battery, and it's the one I could more or less solder before, but with these bad joints, like mini joints that are just enough to solder a cable and that's it. Then I tried this method with the 18650 battery I told you was impossible, and it's way more difficult, but again, I tried at 300ºC. Doing the same now as I've done with the AA battery, this is the result on the 18650:



Same technique, way worse result. As I was expecting, some batteries are harder than others. Anyways, I've tried to scratch that, remove it by using lateral force... nothing, that bubble is really well stuck on there.

 

What? Is that some kind of joke? Because I didn't get it.

There are a few members here that are dense like you seem to be, people that no matter how many people tell them things that don't agree with their preconceived notions, they will continue to argue that they are right and the world is wrong. Gerry is in reference to the one guy like that who claims to, be a teacher and is writing a electronics book. So I was saying you act like one of his students, his "kids".

 

Gerry's kids - - - I was thinking you meant "Jerry's kids", one of whom was a former brother-in-law (now deceased). Jerry as in Jerry Lewis - the comedian / actor who sponsored [{edited for correctness} Muscular Dystrophy.]

 

Jerry Lewis - the comedian / actor who sponsored Polio research.

Jerry's kids - Muscular Dystrophy.

It may sound counter-intuitive, but sometimes when you are trying to solder to a heat sensitive device, using a *higher* iron temperature will give better results.

With an iron temperature of just enough to melt the solder, heat flows away faster than you can put it in and you end up raising the temperature of the whole system to the melting point of your solder.

With a higher iron temperature, you can get enough heat to the area you are trying to solder to so that you can complete your connection before the heat has a chance to flow away.

 

There are a few members here that are dense like you seem to be, people that no matter how many people tell them things that don't agree with their preconceived notions, they will continue to argue that they are right and the world is wrong. Gerry is in reference to the one guy like that who claims to, be a teacher and is writing a electronics book. So I was saying you act like one of his students, his "kids".

Oh, no way I would have known that then. Yeah, I am "dense" as long as the answers don't seem to explain to me anything and are as generic as a forum user reply, and while I find contradictions. I'm so dense then, because I don't see clarity.

Since I've read many, many, many wrong things in forums, yeah, I can perfectly be all alone against "the world" (quite adventurous to call 10 users "the world"), because I don't get convinced easily just because. I ask a lot of things because I like to know things, how they work, understand them, and I know that many, many people, specially in internet, will reply without really knowing what they are talking about, or they simply will repeat what others say, without questioning.

In occasions, you will find here and there a super user that will answer point by point all your questions, explaining perfectly fine why and giving you solid reasons. But, I must admit that's a rare case.

This is not an attack, by the way, to any of you, because there's always a user that gets offended. This is what I think is the reality of internet. Some of your answers really helped me and I thanked you for that.