Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [flux]

Refers to flux chemicals used in soldering. Use the magnetic-flux tag when referring to magnetic field changes.

Flux facilitates processes. To solder joints with impurities like dirt, oil or oxidation, the flux allows the solder flow and stick to the underlying metal. Some fluxes go beyond the simple prevention of oxidation and also provide some form of chemical cleaning (corrosion).

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Are solder fumes bad for me?

I do a fair bit of soldering (lead-free). Is breathing in solder/flux/paste fumes actually going to harm me? Are cheap fume extractors worth buying?
Toby Jaffey
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What does "no clean" solder actually mean?

I bought some solder that says it doesn't require cleaning. The description specifically says "Eliminates the need and expense of cleaning". But there's still a lot of some substance left on my board that I can't easily clean off. What is this…
Stephen Collings
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Removing rosin flux residue from PCB

I have a nice looking purple PCB from Laen's batch service, which I have assembled using rosin flux. I have cleaned the board as best I can with isopropyl alcohol, which gets rid of the tackiness of the rosin, and also improves the dielectric…
Zuofu
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Is acetone or isopropyl alcohol better for removing rosin flux?

For removing rosin flux from my board, should I use Acetone or Isopropyl Alcohol? I need an easily available solvent.
MetricSystemAdvocate
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How does flux work, chemically, and what are the products?

Ususally, electronics solder comes with a built-in flux core. Among the solders I have laying around, I have a silver/tin solder with an "F-SW-21" flux core (ISO 9454-1: 3.1.1, this is zinc chloride and/or ammonium chloride), and a lead/tin solder…
Martin J.H.
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Solder Flux Classifications

I was at Fry's yesterday, looking for some thin solder to use on an Adafruit kit with through-hole components. Two of the solders I found were labeled RA Flux and No Clean, respectively. An engineer who was present said that with my use-case I…
J. Polfer
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How can I solder to stainless-steel semi-rigid coaxial cable?

I need to run coaxial cables into a cryostat, and because copper conducts too much heat, I decided to use semi-rigid stainless steel cables. As far as I can tell, both the shield and the inner conductor are made of stainless steel. I want to connect…
Martin J.H.
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Solder Paste vs Solder Flux

I bought a "Solder Paste". It is in quote because I'm not really sure if it's a Solder Paste itself. I researched about what Solder Paste is and, by definition, is defined as a mixture of small solder spheres with flux. It's also grey-like in…
J. A. De la Peña
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What happens if a solder joint cools before all the flux has evaporated?

Sometimes, when soldering, I see little bubbles come out of the hot joint. Presumably, this is the flux evaporating and escaping as a gas. What happens if I remove the iron and let the joint cool before all of those bubbles can make it out? Can…
Maxpm
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What are those black spots in these lead-free solder joints?

I have just changed to lead-free solder (I'm now using Chip Quik's "SMDSWLF.031, a Sn96.5/ Ag3.0/ Cu0.5 solder with 2.2% no-clean flux) but I'm not sure what I'm seeing when inspecting my boards. The following pictures show an example: the first one…
MV.
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Effects of no-clean flux or RMA flux residue on signals

I keep on hearing that no-clean solder paste or flux is bad for analog or digital signals because it makes analog signals "noisy" and promotes cross talk on digital signals. Like this claim: Flux residues can add noise on analog-to-digital…
Voltage Spike
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Why does the electronics industry use the adjective "organic" when it adds no information?

This has been nagging me for a while. I'm an engineer, not a chemist, so I've probably misunderstood something. The electronics industry uses the adjective "organic" a lot when describing materials. According to Ye Olde Wikipedia, an "organic…
user4718
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Which flux type to use for SMD hobbyist (home-made) PCB?

"Short" question Which flux type to use for SMD hobbyist (home-made) PCB? How to know if a specific flux (e.g. F-SW-33) is no-clean or require cleaning. How to know if a specific flux conduct electricity? What is the impact of Halides? Longer…
Adrian Maire
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Components to avoid using on an ultrasonic cleaner

What components populated on a PCB are not safe to clean in an ultrasonic cleaner? It is not limited, but I specifically wonder below components if they are safe to use or some requires special attention (low temperature, low power, or what kind of…
Angs
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Recovering from failure to clean off solder flux

I'm currently building a prototype device at work, that involves a QFN-64 0.5mm pitch IC (a PIC microcontroller) soldered onto a SchmartBoard|ez prototyping board. The SchmartBoard instructions call for the use of flux, which is not something I…
jasonharper
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