Questions tagged [flux]

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

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395 views

Hakko FX-888D Iron Issue

I just got a new Hakko 888D for Christmas. I have used it a bit since then, and I'm using the wet sponge, brass sponge, and some RadioShack tip cleaner to maintain the tip quality. The issue I am ...
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2answers
5k views

When do I choose to use a rosin based flux or rosin-free flux?

What are the general guidelines for determining when flux should or should not have rosin? Thanks
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3answers
73 views

Will my wires have current stability issues?

first post here. I'm currently making a set custom sleeved/crimped cables for my computer's modular power supply, and my crimper isn't very good, so for extra security, I've soldered all the crimps, ...
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2answers
9k views

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 ...
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4answers
231 views

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. ...
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1answer
243 views

One flux for all electric soldering?

My understanding is that standard electrical soldering fluxes will not be effective on aluminum or stainless steels. Is that correct? But are all rosin fluxes adequate for the other metals ...
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1answer
1k views

Wireless Power Coil - Is this shielding? Field shaping?

I'm taking apart a Qi wireless power transfer receiver. The coil is etched into the pcb. The entire coil area (approximately 3.75 x 4.5 cm) is covered by a rectangular piece of hard, brittle material. ...
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1answer
2k views

Induced voltages and flux within a transformer and their polarities

This is a multifaceted question, and is more to see if I understand what happens inside a transformer. I understand the general idea behind transformers: Alternating voltage that is applied to the ...
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1answer
541 views

Hand soldering QFP component

I recently came across this video on YouTube, in which the guy is soldering a .5 mm QFP component. Hand soldering a .5 mm QFP Chip As I haven't done a lot of soldering in my life (and never used ...
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1answer
598 views

What is the difference between flux and flux-linkage? how to calculate inductance of transmission lines?

in calculating inductance of a single current carrying conductor how flux linkage is calculated?why flux is multiplied by a factor (X^2)/(r^2) to get flux linkage. see the following images:
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8k views

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 ...
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1answer
1k views

How long can you leave flux on a PCB?

How long can flux be left on a PCB? I am working on one of my PCBs and I have put flux on it to solder. Can I leave it overnight. Is that ok? Or how long can flux be on the board? update: 715 water ...
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3answers
10k views

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 ...
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1answer
773 views

Can liquid soldering flux be refrigerated?

I've been upgrading my soldering mojo lately and have collected an assortment of liquid fluxes. The Kester 951 and Kester 186 datasheets state shelf lives (1 and 2 years respectively) when stored ...
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1answer
2k views

in order to understand bldc motors and their working principle, I read a lot on the web, and I see them like a tripolar steppers, am I right?

I was told my previous questions were not well received by the community, it was never my intent to post a repeated question or a bad formulated one, and english is my second language, not my maternal ...
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3answers
51k views

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 ...
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2answers
1k views

Chipquick SMD291 No-clean Paste Flux - Conductive?

I'm using this brand and type paste flux, and it works very well... except for one small problem. After assembling 5 prototypes, most had bizarre issues, which were resolved when the flux was removed ...
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1answer
227 views

Mitigate the effects of magnetic induction heating in a three phase AC system

To mitigate the effects of magnetic induction heating in a three phase AC system, it is common practice to group the conductors and to keep them in the same raceway. Also, three phase power is ...
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4answers
2k views

Does a 1 watt 660nm LED put out more radiant flux than a 1 watt 630nm LED?

Given two LED chips consuming same or very similar amounts of DC power, One emitting light peaking at 630nm, The other at 660nm, In terms of output of (but light irrelevant to the sensitivity of ...
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2k views

How to clean “no clean” flux with a 3L ultrasonic cleaner

I am doing some small batches of PCBs, like 100 each time, using solder wire with no clean flux core. I am using this solder wire. The datasheet recommends IPA and water at 60º. Usually, I clean it ...
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3answers
553 views

How do I pick a flux cleaner that's safe for use without industrial ventilation?

I was looking at getting this flux cleaner: Fluxclene FLU200D but then I noticed that in the datasheet, it mentions an inhalation toxicity of 300 ppm. That sounds like it's easily exceeded by just ...
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1answer
687 views

Solder sticks to PCB (not just the pads!)

I'm having a severe problem with solder adhering to the FR4 PCB material. I made my boards (myself, my first time) using positive developer and etchant on a pre-sensitized board. I washed the etchant ...
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2answers
9k views

How does flux exist in a transformer?

What I understand about working principles of ideal transformer: We apply an alternating voltage at the primary side. This creates a flux inside the transformer core (\$\Phi_p\$). Some voltage is ...
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1answer
3k views

Polarity of the induced voltage on inductor for an applied magnetic flux according to the Lenz's Law

I'm trying to visualize the Lenz's Law on a practical inductor. The Lenz's Law says that $$ \mathcal{E} = -\dfrac{\partial \Phi}{\partial t} . $$ Now, assume that there is a magnetic flux inside ...
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2answers
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Where does the flux go when desoldering?

I have a piece of equipment with a right angle miniUSB port that went bad. After pulling the old port I have a big blob of solder shorting out the traces. So obviously I must get rid of the blob ...
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1answer
2k views

Accidentally used plumbing flux on a PCB; How do I remove it to reuse the board?

Two weeks ago, I picked the wrong tub of flux from my toolbox and used it for making a 9VAC -> 5VDC adapter. I fluxed all the components and soldered it down before realising I was using PLUMBING flux!...
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15k views

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 ...
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3answers
21k views

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 ...
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1answer
1k views

How to calculate flux density in a toroidal CT that has an electrical line pass through the center?

I have seen the Biot-Savart equation but I don't know how to apply it. Also does the conductor length need to be considered finite and equal to the core length or will the calculation be for infinite ...
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3answers
5k views

Magnetic path length and Permeability relation

In a transformer, increasing the magnetic path length reduces flux and permeability and increases reluctance of the core? if yes, why does the equation of relative permeability of a gapped core show ...
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4answers
6k views

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 ...
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1answer
3k views

Can I use Formula SP-30 self-cleaning acid paste flux?

I am a complete noob when it comes to soldering. I've only done a little bit in the past and it was years ago. Today, I bit the bullet after reading about how to solder and purchased some soldering ...
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1answer
361 views

F-SW22 vs F-SW33 flux. What to these figures mean?

I was thinking of purchasing a no-clean flux pen from my supplier, but there are two options, F-SW22 and F-SW33. What do these codes mean and what types of job is each suitable for?
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3answers
7k views

Why voltage lags by 90° from magnetic flux?

I was not sure if I should write it here or on Physics board, but I will give a try. As I understood current (generally emf) can be generated in a system by varying magnetic flux. For example, let's ...
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1answer
273 views

What Can Be The Cause Of Low Voltage After Resoldering?

I had to resolder mosquito zapper's black and red wires back after zapper fell on the floor and black wire detached and later red wire detached when i was trying to solder black wire back. After ...
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596 views

Will a faster rate of change of flux improve electricity generation?

From what I remember about electricity generation, a varying magnetic field is used, either the magnetic field or the coil moves to generate electricity. e = dB/dT where e = voltage induced B = ...
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2answers
995 views

DIY Fluxes with ethanol-propanol-x-nol

Got inrested in DIY fluxes by reply here. Can you substitute rosin-core wire with DIY flux and non-rosin-core-wire? How and where to actually use DIY fluxes if you have rosin-core wire? Which % of ...
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2answers
4k views

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 ...
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10answers
175k views

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?

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