When should additional flux NOT be used?

[z-adamson]

I have gotten into the habit of using flux paste religiously for soldering and desoldering. Things just go easier and things just come out better.

I began to wonder the other day if there is such a thing as a situation where additional flux should not be used.

Hmmm, what do you think?

 

[Binkman]

Sure! where you don't need it.

 

[ConradH]

I'd be careful around unsealed trimpots or any place where you can't clean it off if need be. Some types of IC sockets perhaps.

 

[cpt_paranoia]

What sort of flux paste are you using?

 

[z-adamson]

What sort of flux paste are you using?

http://store.caig.com/s.nl/it.A/id.2555/.f?sc=2&category=2341

 

[Hajidub]

To answer the OP's question, flux in moderation if the component is close to delicate solder joint or heat sensitive component.

 

[gadget73]

I dont use extra flux beyond what the solder itself comes with unless its an old never-soldered terminal or its just being stubborn and refusing to take new solder.

 

[z-adamson]

So, lets say you use flux in a situation where it is not technically needed, yet it was easily cleaned up afterwards and there are no unsealed switched or trim pots nearby.

Are there any potential problems here?

 

[petehall347]

one problem might be dropping the flux pot and breaking something .

 

[ConradH]

FWIW, years ago I watched a NASA certified solderer and she applied a bit of extra flux to almost every joint. And of course, cleaned off every joint.

 

[Hyperion]

I dont use extra flux beyond what the solder itself comes with unless its an old never-soldered terminal or its just being stubborn and refusing to take new solder.

Exactly, using extra flux, (most 'wire' solder already has flux cores in it), is therefore a waste and of course needs additional cleaning. I have a small tub of paste flux (kept in the fridge ) and useful though it is, I use it only rarely.

 

[ConradH]

Remember that when you add flux, you have a choice of many different types. The most common are the three rosin types, R (rosin), RMA (rosin, mildly activated) and RA (rosin, activated). The choice depends on just how much cleaning action the parts in question need. https://www.finishing.com/library/flux.html and various others. I only add flux if the joint is difficult, so something reasonably active would be my choice. I use a 30+ year old bottle of Kester 1588, an RA flux. A good modern choice might be Kester 1589.

 

[Blue Shadow]

I use a 30+ year old bottle of Kester 1588, an RA flux. A good modern choice might be Kester 1589.

Thirty years and the part number only goes up by 1. Maybe they got it right the first time.

 

[Blue Shadow]

http://store.caig.com/s.nl/it.A/id.2555/.f?sc=2&category=2341

First thing I noticed when I looked at the specs for this material was the Acid Number. We don't use acid flux in electronics but since I have a bit of a background in Tall Oil and it has an associated rosin acid number, I was ok that this flux was the right one to use on electronics. Just interesting that the word acid number would jump out to me.

Let me finish by saying this is NOT an issue with this flux so let's not get all excited about that word in the specs.

 

[avionic]

The more you use the more you have to clean up when done soldering.

 

[z-adamson]

FWIW, years ago I watched a NASA certified solderer and she applied a bit of extra flux to almost every joint. And of course, cleaned off every joint.

This is basically what I have gotten into the habit of doing.

 

[z-adamson]

The more you use the more you have to clean up when done soldering.

If thats the only downside, then I guess it's not such a bad thing to use regularly after weighing the pros and cons.

 

[merlynski]

I like to put extra flux on my de-soldering wick, almost never use it when soldering.

 

[petehall347]

I like to put extra flux on my de-soldering wick, almost never use it when soldering.

me too if i have to use wick as its only way it will work even though its supposedly in the wick already

 

[spinroch]

Don’t use it for brushing your teeth. Not recommended.