Greetings,

I've been diving into the world of soldering and flux recently, and I'd like to check my comprehension with those more experienced in this field. This is my current understanding, and I would greatly appreciate your input if there are any misconceptions or omitted parts:

During soldering, we heat up metals that can oxidize when they come into contact with air. The oxidized layer that forms can hinder the solder's ability to properly bond with the metal, which is where the role of flux becomes critical.

My understanding is that flux possesses reducing properties. It acts to remove existing oxides and prevents the formation of new ones during the soldering process, ensuring a strong bond between the solder and the metal.

However, the residues that the flux leaves behind can cause corrosion over time. This becomes a specific issue in electronics, as the corrosion can lead to increased electrical resistance, formation of unintentional conductive paths (which could cause short circuits), or even result in complete component failure.

Therefore, in the realm of electronics, it becomes necessary to use non-corrosive fluxes, such as rosin flux, to avoid these problems. I also understand that there are other types of flux, like acid core flux and plumber's flux, which are corrosive and thus unsuitable for electronics.

Is my understanding accurate? Are there any areas that I've misunderstood or overlooked? Any clarification or additional insights would be hugely beneficial!

 

Generally accurate

At one of the places where I shop for electronic parts and supplies flux can be bought as paste, with the containers labeled with the pH.

Neutral flux does not corrode connections and does not have to be cleaned from most of the circuits I make. (The circuits I make are very sensitive to leakage currents)

 

I would not over think this.

I use 63/37 Sn/Pb solder with rosin in the center core because it is easier to use than lead-free solder.
Use lead-free solder if it is a requirement for manufacturing.

After soldering, clean the board if you have to. In most cases, I don't bother to clean the board unless there is a particular reason to do so.

 

Hi denni,
You may find that sometimes, especially when soldering partially corroded/oxidized terminals, like say 0.25inch connectors tags, that a more aggressive solder and a 60Watt iron will be required.
So having a little of each type on the work bench will be helpful, you should use a liquid cleaner to remove any residual flux.
I find a small reel of Aluminium solder with a resin inbuilt flux ,gets the oxidized parts tinned OK.

E

 

Welcome to AAC!

During soldering, we heat up metals that can oxidize when they come into contact with air.

Oxidation can have already occurred before you apply heat.

My understanding is that flux possesses reducing properties. It acts to remove existing oxides and prevents the formation of new ones during the soldering process, ensuring a strong bond between the solder and the metal.

Flux improves solderability of surfaces that have an oily residue on them. It can also help with heat transfer.

 

This is the one I've used for decades. The small bench bottle. It does a consistent, great job, with no noticeable residue. I use it on mostly small lugs & wires.