In the internet I found only articles about do you need to use flux or not, but my friend uses the acid as a replacement to flux for MCU, so is it a wrong action or not?
Yes! There are some fluxes that are acid in nature.
In soldering, flux plays a critical role by cleaning and preparing the surfaces to be soldered, ensuring a strong, reliable connection. Here’s what flux does:
- Removes Oxidation: Metals naturally form a layer of oxide on their surface when exposed to air, which can prevent the solder from bonding properly. Flux removes or prevents oxidation, allowing the solder to adhere to the metal surfaces.
- Improves Wetting: Flux helps the molten solder spread evenly (a process called "wetting") across the surfaces, which is essential for forming a good electrical and mechanical connection.
- Prevents Reoxidation: During the heating process, flux helps protect the surfaces from reoxidizing, ensuring the solder bonds properly.
- Promotes Flow: Flux lowers the surface tension of the solder, allowing it to flow smoothly and fill any gaps between the components and the joint.
Without flux, the solder might not adhere properly, leading to weak or unreliable connections.
1 Like
Do you mean acid based flux as opposed to rosin based flux?
1 Like
Or does OP mean 'koningswater' (mixture of sulphuric, hydrochloric and nitric acid)....(used to solder copper pipes with a direct flame).
Makes really nice and clean surfaces!
And will eat your board in the longer term...
2 Likes
You should use flux intended for electronic soldering! Plumber's flux is usually acidic, and it shouldn't be used for electronics. You can probably "get away" with acid or acid-flux if you wash it off after soldering. But electronic manufactures and experienced hobbyists use flux intended for rhe purpose.
I use something like this but I didn't buy a gallon of it. Water soluble flux is supposed to be cleaned-off after soldering to prevent corrosion so I thought it was acid-based, but this one says 'PH neutral". You can clean the board with water after soldering, but some switches & pots are not supposed to be submerged in water.
Traditional rosin flux looks ugly if not cleaned but it doesn't hurt anything but normally it is cleaned-off with flux remover.
There is also "no clean" flux which leaves a clear residue that's not harmful and not too ugly.
1 Like
- It is a wrong action.
There will always be some acid remaining even after cleaning, the copper will eventually deteriorate.
2 Likes
That type of flux was used by my manufacturing company. It is an ORGANIC acid that is activated by the heat of soldering. The residue must be cleaned and is a pain to do. Use a toothbrush to thoroughly scrub the soldered areas and use lots of flowing water to flush off the circuit board.
My experience with a board that was not processed correctly was that after a year or so the flux will form conductive paths that will make for erratic operation.
Another aside: That flux was used in a wave soldering machine. I was kept in a stainless steel tank. After an unknown number of years, the flux had eaten holes in the tank. Nasty stuff!
Using acid for soldering is extremely expensive and it'll likely attract attention from law enforcement. It's also very tricky to get the 100ug or so from a piece of paper the size of a small stamp on your soldering iron.
Whis is to say...what kind of acid is your friend referring to? There are literally millions.
And generally speaking - no, just use flux intended for soldering electronics components. It's dirty cheap; why would you bother creating vapors that literally corrode your mucous membranes? It's dumb.
1 Like
Actually, I have almost a full spool of solder out in the shop that has organic acid flux in the core of the wire.
1 Like
This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.