2 questions about flux

[apelly]

1) For my whole life, and for the first half of my current spool of solder, flux residue has been brown and fairly minimal. Now it's green, gunky and plentiful. Is this due to soldering at a lower temperature? I'm around 330C at the moment.

2) What do you guys use to clean this up? Acetone works, but makes the solder mask sticky. Any suggestions?

Aaron.

[Alex]

Regarding #2, you can try isopropyl alcohol (IPA) or a purpose-made flux remover (eg. Electrolube LFFR).

Alex.

[deth502]

+1 to alex. ive used the flux remover spray before and it works great. i just dont do large enough jobs for me to justify buy it again. if i do a repair with a few joints, or a small project, i just scrape the heavy flux with a pick and brush the board. but yeah, if youve got a large board to clean, the spray is the only way to go.

[mcinque]

2) What do you guys use to clean this up? Acetone works, but makes the solder mask sticky. Any suggestions?

Trichlorethylene. Cheap, well tolerated by solder mask and components, works very very well for me, and it doesn't leaves residues at all.

[nanofrog]

+1 to Alex and deth502. 

Trichlorethylene. Cheap, well tolerated by solder mask and components, works very very well for me, and it doesn't leaves residues at all.

Works well, but likely hard to get now (carcinogenic & environmental concerns).

[apelly]

IPA it is. Thanks guys.

I'd still like to know what's up with the green flux though. Soldering leaded onto lead free tinned pads? Seems unlikely. PCBs are coated with nickel aren’t they?

[kizzap]

Are you saying that the flux changed colours half way through the roll of solder? are you perchance working on new boards that you haven't used before?

The only other option I can think of is that the solder manufacturer changed their flux recipe half way through a cycle and it just so happened to change in your roll.

-kizzap

[apelly]

Are you saying that the flux changed colours half way through the roll of solder? are you perchance working on new boards that you haven't used before?

Yes and yes. Haven't tried going back to something I've worked on before. Will do.

The only other option I can think of is that the solder manufacturer changed their flux recipe half way through a cycle and it just so happened to change in your roll.

-kizzap

Seems pretty unlikely.

Aaron.