What is FLUX in soldering


#1

Hello
What is Soldering Flux What does it do how it is made


#2

Did you bother trying a google search for “soldering flux”?


#3

Hello Sir,
I have searched it take reaction with solder but why it is used


#4

I think you didn’t read the result carefully, for example https://hackaday.com/2017/02/23/what-the-flux-how-does-solder-work-anyway/ is almost at the top and and in my opinion explains why it is used.


#5

Hello
How it join copper,aluminium,LED Leads
what material does LED leads are made of …
and why we add flux in it does it make strong joint


#6

What is this sem_sn63_intermetallic_labeled


#7

Flux is a chemical that violently rips oxygen from other substances when heated, It is used during soldering to remove any oxide layers and expose clean base metal.

With the metal cleaned by the flux the solder and the base metal can begin diffusing into each other (e.g. the copper or gold actually partly dissolves into the solder, due to this, the surface area of the junction is massively increased, making the joint strong with a very low risk of delamination of the junction.

In that image, I believe it is a copper - solder joint, the substrate is the copper of the pad, the intermetallic layer is where the oxide has been stripped making it shinier, and likely dissolved some of the solder, the above later is little clusters of bubbled off copper in the solder.

To learn more about solders dissolving base metals “Gold Embrittlement of solder joints” is a common example, gold plating will reduce reliability in either high vibration environments or wide temperature swing environments if you don’t have a long enough heat soak time on your re-flow process to ensure most of the thin plating has been dissolved.


#8

Hello
What is inside Flux at what temperature it melt


#9

The most popular for leaded solder is rosin, this is derived from plants, as to the exact source, and temperature, that varies based on how the manufacturer produces it, even for the plant based rosins, there are about 17 types, and by different refinements or additives the activation temperature can be changed. so Its hard to specify anything exact without a reference to what you have on hand.


#10

Helllo
I have found this what does it do download%20(1)


#11

Looks like some kind of brown sugar, maybe you can use it as sweetener.

Seriously, how do you think we can tell you what it is? If it’s rosin and you want to use it as flux, why don’t you just test it? If you wanted to make flux, why didn’t you ask that in the first place? And why do you ask that in the KiCad software forum? There must exist better places where people know more.


#12

Hello
How to know more about flux what is chemical reaction involved in it


#13

What material your LED leads are made of, you have to ask the manufacturer or at least read the datasheet of the LED. Sometimes it’s mentioned there. On the leaded LED’s I preferentially use, it is (lead free) tinned copper.
I bet it’s not aluminum, as that is very difficult to solder (it needs special flux).
Flux does not make a strong joint. It enhances the wetting of the solder on the components and the PCB.

Walter


#14

You mean the intermetallic layer?
That has nothing to do with flux, it is an alloy forming between the solder and the metallic substrate.Some of that metal dissolves in the molten solder and forms that layer between metal and solder.

Those brownish chunks look like raw colophonium, one of the many active components in flux. It gets dissolved in solvents, mixed with other stuff, just as the manufacturer of the flux likes.

You don’t want to know the answer in detail (its of no practical interest anyway), not if you don’t have extensive knowledge in organic chemistry. (And if you had that knowledge, you didn’t have to ask :wink:)
Believe me, I’m about halfway there myself :slight_smile:

Walter


#15

@RITESH
Questions like these are ok to ask here I guess, but if you want more in depth answers there would be:

or

or maybe

https://www.eevblog.com/forum/beginners/

We’re specialized in KiCAD support here.


#16

I’d say marginal given this is pretty fundamental stuff and the user seems to confuse the site with google,


#17

If you’re new to soldering, I recommend this video:


#18

What material your LED leads are made of, you have to ask the manufacturer or at least read the datasheet of the LED. Sometimes it’s mentioned there. On the leaded LED’s I preferentially use, it is (lead free) tinned copper.
I bet it’s not aluminum, as that is very difficult to solder (it needs special flux).
Flux does not make a strong joint. It enhances the wetting of the solder on the components and the PCB.

Hello
some LED get rust due to which it does not solder why :game_die:


#19

Hello
What is soldering temerature of LED


#20