The way forward (Soldering).

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Yes indeed they must have been floating around like asbestos fibers.
I have found whiskers on plated steel of an unknown metal in a 1950s signal generator.
 

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It is interesting to see efforts at making flux, I like it.

When I select a flux, my concerns are:
1. Basis metal to be soldered to.. This will determine the chemistry and activity of the flux. Nickel for example will require a more aggressive flux than gold.
2. Solder alloy.. This will determine the temperature range of activity required. A lead free flux is designed to activate at the temps required, 221 to 232 C. If flux designed for eutectic tin/lead is used with lead free (bismuth excluded), it may burn before the alloy melts. Conversely, a lead free flux may not activate at the lower temps.
3. Residue activity.. As many RMA and RA fluxes use zinc chloride, the residue contains hydrogen chloride. Some applications do not take well to that.
4. Component heat tolerance.. Many older plastics do not react well to lead free soldering temperatures.
5. Tip temperature.. Too many times in industry as well as diy, they use a small tip and elevated temp to speed the process. The problem is the work temperature ramps fast and can speed past the temp required for soldering, into the plastic compromising area. Better to use a higher mass tip set lower, relying on the heat capacity to bring the work up to temp.


Soldering any alloy to any basis metal is trivial when these factors are considered well. Proper flux and cleaning are by far the best bang for the buck.

Jn
 
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Soldering any alloy to any basis metal is trivial when these factors are considered well. Proper flux and cleaning are by far the best bang for the buck.

Jn

Since that has not been my experience soldering to zinc or chrome plated steel (cheesy connectors) what are your recommendations?

A chart of the combinations would be really helpful since all you mention should be posted somewhere. With lead free solder and other tech "innovations" the old eutectic solution is no longer universal.
 
Since that has not been my experience soldering to zinc or chrome plated steel (cheesy connectors) what are your recommendations?

A chart of the combinations would be really helpful since all you mention should be posted somewhere. With lead free solder and other tech "innovations" the old eutectic solution is no longer universal.

I typically use RA water based flux when the base metal is a difficult one. But since it's so active, it should only be used to tin the surfaces, and never used to tin a stranded wire as it will wick and kill the wire over time.

I use it all the time on stainless, inconel and nichrome.

The only thing is, clean the flux off very well after tinning, then use regular flux for the final connection.

The superior flux website has different flux formulations for various metals. I used it about 27 or 28 years ago.

John

PS..it's still there, found this:

Finding a Flux by Application | Superior Flux & Mfg. Co.
 
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Great!

I am both old and not.

I have avoided lead free solder as I found it so unworkable, that it made me doubt I'd ever learned to solder at all!

So I too stash away good leaded solder. I also have some which isn't so good, fluxes badly, and stinks. I only got it for finer work.

The lower temp stuff with silver in is nice to use.

Anyway ROHS forces most of us to use lead free at work.

The latest lot I have works well, though seems finicky with flux, and could probably use more flux than the core provides. It either flows beautifully, like leaded solder, or just goes gloopy. But that the best I've used yet. IIRC its perhaps 0.5% Cu.

But your point is correct. The alloys are getting there....but just noone knows which alloy to use, or there are so many it's difficult to select the best.

Anything which helps further my understanding of how on earth to find a good ROHS solder, is welcome news. (Even if I'll still prefer leaded until I find something as good)
 
I am both old and not.

I have avoided lead free solder as I found it so unworkable, that it made me doubt I'd ever learned to solder at all!

So I too stash away good leaded solder. I also have some which isn't so good, fluxes badly, and stinks. I only got it for finer work.

The lower temp stuff with silver in is nice to use.

Anyway ROHS forces most of us to use lead free at work.

The latest lot I have works well, though seems finicky with flux, and could probably use more flux than the core provides. It either flows beautifully, like leaded solder, or just goes gloopy. But that the best I've used yet. IIRC its perhaps 0.5% Cu.

But your point is correct. The alloys are getting there....but just noone knows which alloy to use, or there are so many it's difficult to select the best.

Anything which helps further my understanding of how on earth to find a good ROHS solder, is welcome news. (Even if I'll still prefer leaded until I find something as good)
25 years ago (give or take), I was thrown into the lead free fray. I developed soldering processes using lead free... It works extremely well when all the chemistry is considered. I note that I did use a few tons of tin/silver. At the time, I was the worlds largest consumer of eutectic tin silver..

That...and a quarter.:D

Jn

Ps. After that, I had to work on reliability for a big machine where some vendors and many piece parts were ROHS... I am ready to retire....
 
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All this talk of lead, and no one ever mentions cadmium. You know that yellow powder on old screws and chassis - that used to be cadmium plating - and being in powder form due to oxidation does make it more potent.

Like there was never any warnings on using hot air guns to remove paint from old doors ...

However, I am a bit unhappy that I am unable to make my own choice and buy leaded solder. In my local Elfa Distralec, in Sweden, I can see it in the locked cabinet, and professionals are allowed to buy it, but not hobbyists like myself. Since I am fixing old electrical equipment, I am presuming that mixing leaded and unleaded is going to be an issue.

Paracetamol is not good for me in large doses, but I can buy small packets. Why can't I buy a couple of metres of 0.7mm leaded solder, which would last me 6 months probably?
 
All this talk of lead, and no one ever mentions cadmium. You know that yellow powder on old screws and chassis - that used to be cadmium plating - and being in powder form due to oxidation does make it more potent.

Like there was never any warnings on using hot air guns to remove paint from old doors ...

However, I am a bit unhappy that I am unable to make my own choice and buy leaded solder. In my local Elfa Distralec, in Sweden, I can see it in the locked cabinet, and professionals are allowed to buy it, but not hobbyists like myself. Since I am fixing old electrical equipment, I am presuming that mixing leaded and unleaded is going to be an issue.

Paracetamol is not good for me in large doses, but I can buy small packets. Why can't I buy a couple of metres of 0.7mm leaded solder, which would last me 6 months probably?
One solution is to go ask the local TV/Radio repair shop for a few metres...that's what I did as a kid in my early hobby days and they just gave me some.
 
Thanks for opening this thread and to those who posted.

So, it is time for me to stock a large stash of leaded solder for my remaining years. Well, I am past 50% of an average lifespan.

Lead free solder is terrible compared with good old leaded solder. I have been soldering since I was an adolescent: I have no patience for this unleaded stuff.

Regarding the dangers of lead poisoning, it would be interesting to read about its incidence. How many lead poisoning events did take place when solder was leaded? Lead poisoning can be treated through chelation therapy, but damage to the brain cannot be undone.

The key question is, what was the incidence among leaded solder users who ended up with lead poisoning requiring treatment and with debilitating effects? Where are these statistics?
 

PRR

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Electronic work with a small tip is teeny lead-fumes compared to factory dip-vat wave-soldering. (Or making "tin" roofing sheets.)

The more immediate hazard in small bench solder is the rosin fumes. They irritate most noses, but a few people get severe allergy. Use a fan.
 
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I sure different fluxes have different shelf lives but all the stuff i have here works and most is at least 10-15 years old. I was told by a sales guy for an industrial distributor years ago that Ersin flux was harder on tips. . . I can see water washable flux having a limited life. Pure rosin (tree) flux may decay but it seems unlikely cased in metal.

I know that if you are a production operation with high reliability concerns you would not want old stuff. Many won't work with chips that are over 6 months from MFR. Too much risk. Very real for SOTA BGAs etc. Probably not an issue for the types of stuff we all do.
 
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