Neutralising Bakers No. 3 fluid

[PippinParticipant @phillspowart84010]

Did some soldering of mild steel, using Bakers No. 3 as a flux. 3 weeks later, and anything that went near the job won’t stop rusting. Have scrubbed with scotchbrite and evaporust then oiled up, just goes orange again. How on earth do I stop it?

[JasonBModerator @jasonb]

Bicarbonate of soda mixed with water.

[Neil WyattModerator @neilwyatt]

It’s a mixture of highly aggressive chlorides. There’s no real neutraliser, the best you can do is wash it off immediately with warm water, wash it off again, and then wash it off once more.

For steel, you are better off using a traditional rosin flux or a no-clean plumbers flux for lead free jointing. Steel really doesn’t need a aggressive flux if you clean it first.

[alecsParticipant @alecs]

Ive always used bicarb soda solution then washed that off with soapy water.

[Howard LewisParticipant @howardlewis46836]

Bakers Soldering Flux, as Neil says, is a mixture of acidic chlorides (Mosrly Zinc dissolved in Hydrochloric acid)  So needs to washed off IMMEDIATELY after soldering is completed.

Being acidic, an alkaline solution will neatutralise it, but don’t go mad with caustic soda, or you’ll exchange one chemical corrosion problem with another!

Lots of washing and mild alkalis.

Howard

[PippinParticipant @phillspowart84010]

Thankyou all. Quite amazed how little it needs, so stuff rusted just from me using the same nitrile gloves I’d used for the soldering.

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