Do you use "flux" when soldering?

[Jim C]

I have had problems getting solder to stick to the back of pots. Will using flux help?

It will help, but IMO you need to lightly sand the plating for the best adhesion.

Have always used flux even with Ersin multi core solder; for general work I've been using LACO regular soldering flux but would appreciate advice as to if this is the best brand for general electronics soldering.

BTW, the work I've seen for both standard MIL-SPEC as well as nuclear submarine appications call out for flux and then flux removal after the jobs done.

 

[calebbarton]

Flux is great. It works really well in most situations. You can achieve better joints with flux and the wicking action will help with surface mount parts (or the backs of pots). The only time that flux sux is when it gets stuck to your fingers, shirt, rug, pants, shoes.....you get the idea.

 

[Bassamatic]

I have been managing electronic manufacturing since the 70's. For what you guys are doing - soldering wires to a pot - you do not need flux. Use a good solder - such as the Ersin Multicore and there is no problem.

If one of the parts is dirty or oxidized, it is best to clean it first by scraping or sanding - don't goop on more flux. I have a little wire brush that is perfect for this. If you DO go ahead and use flux, make sure it is NOT acid flux that is used for car radiators, etc.

The reason it is difficult to solder to the back of a pot is that the pot shell is a big heat sink - it is hard to get it hot enough with a pencil soldering iron. You put a little solder on the end of the iron to help the heat transfer and then hold it there and wait until the solder blob spreads out - THEN it is hot enough to quickly attach the wire. If you tin the wire first with a little solder it will stick very quickly.

 

[gnjpowell]

Should always use flux, solder-based or separate, usually in the center (core) of the solder for electronics. The flux removes oxidation from the surfaces to be joined, helps the solder to flow into the joint and prevents oxidation while the joint and applied solder are hot.

 

[Winni111]

I want to refuse rosin in general when soldering components.

Please advise flux, which is washed off normally with water and does not lead to sad results.

Not everything is available, but there are such signs:

FCS - some swear that they do not wash it with water, but with alcohol, while others wash it off with hot water for a hundred years and do not suffer. However, there are reports that it works under the SMD components as a time bomb, and it is not clear whether it can be washed there.

TAGS - of the type also declared as water-washable, how much is bad or good - is unclear.

What else do you have? Maybe How to Use Flux When Soldering Electronics For Beginners - Solderingironguide

 

[byacey]

Do not use any fluxes, paste or otherwise, unless they are rosin based; anything else may be caustic and potentially damage the components.

You can buy prepared liquid flux with a fingernail polish style brush for applying it to the pieces to be soldered. Alternatively, you can make your own from a cheap block of violin rosin, otherwise known as colophony. Chip up some of the rosin and dissolve it in some ethyl or isopropyl alcohol until it creates a viscous, syrup-like liquid. Store in a sealed bottle to prevent evaporation.

This flux is not water soluble, but washes away easily with alcohol or acetone.

 

[40Hz]

It will help, but IMO you need to lightly sand the plating for the best adhesion

Check the specs on the pot before you do however. Some pots made for use in guitars now come with the cases pre-tinned. With those you don’t want to sand since it defeats the purpose.

 

[Lizooki]

Just to note:

The guys that are saying use flux other than the rosin cored solder most of us have experience with are guys with LOTS of experience. ( I also have it)
These are guys who I respect their work and opinions.
BUT, if your are inexperienced in doing this, it's my suggestion to stick with the rosin core solder
and don't add extra.
Not knowing what you're doing can make a mess, let stuff go where you don't want it to, and bridge circuits.
I personaly only use more paste whenever doing something big, needing lots of heat.
Otherwise, I stick to the rosin core solder.

 

[stratovani]

I soldered sapphire negative lenses as part of my job as an endoscope repair technician for about 15 years (retired now). I definitely used liquid flux as it would help the solder flow right where it would need to go in order to get a tight liquidproof seal. I found it very important to find the temperature "sweet spot" when soldering lenses so the metal ring around the sapphire lens wouldn't burn away. Too high and the ring burned off, too low and you had to leave the iron on too long, again burning away the ring. 600 degrees did the trick. I have a Weller digital soldering station, and for pots and jacks I solder at 850 degrees. Also you need to keep the soldering iron tip clean. I use a slotted sponge for wiping off the tip. Another pro tip is to pre-tin wires before soldering on pot lugs, makes it easier to solder.

 

[byacey]

I soldered sapphire negative lenses as part of my job as an endoscope repair technician for about 15 years (retired now). I definitely used liquid flux as it would help the solder flow right where it would need to go in order to get a tight liquidproof seal. I found it very important to find the temperature "sweet spot" when soldering lenses so the metal ring around the sapphire lens wouldn't burn away. Too high and the ring burned off, too low and you had to leave the iron on too long, again burning away the ring. 600 degrees did the trick. I have a Weller digital soldering station, and for pots and jacks I solder at 850 degrees. Also you need to keep the soldering iron tip clean. I use a slotted sponge for wiping off the tip. Another pro tip is to pre-tin wires before soldering on pot lugs, makes it easier to solder.

Also, if using a Weller soldering station, use an appropriate tip for the job at hand. For example, use a large 1/4" chisel tip for fast heat transfer when soldering pot cases and heavy chassis connections, vs. for PC work, a fine 1/16" conical tip.

 

[aborgman]

Also, if using a Weller soldering station, use an appropriate tip for the job at hand. For example, use a large 1/4" chisel tip for fast heat transfer when soldering pot cases and heavy chassis connections, vs. for PC work, a fine 1/16" conical tip.

Absolutely.

...and if you are soldering anything with a lot of thermal mass - more tip thermal mass and higher wattage are your friend.

An underpowered/tipped soldering iron will ruin things much more quickly due to overheating than just about anything.

 

[Heavy Blue]

We used separate flux rather than relying on incore solder in the U.S. Air Force.

Same as the Canadian also. We were trained to always use it.

Excess flux washes off with iso and a brush easy peasy so if one has it there’s really no reason not to.

I’m also going to need separate flux for reflowing joints.

 

[micguy]

Rosin core solder should work just fine for soldering electronic components to each other. Paste flux on top of what's in the solder is helpful when soldering to the back of pots. Although excess flux isn't going to cause failures quickly, it's good practice to remove what you can after you're done soldering; using paste flux where you don't need it makes this cleanup difficult and generally less effective.