- Jan 26, 2022
- Reaction score
To clean off some very hard ceramic flux residue I use for Silver soldering or brazing of Stainless steel it says on the container to use "Caustic soda solution". Of course this will dissolve aluminium, but maybe if you use a diluted caustic solution and soaked COLD for a long period that would loosed the flux without much damage to the aluminium? I find 2 to 4 days of soaking that flux in Washing powder (for washing your clothes) will make it loose enough I can scrape it off easily with a sharp point or knife. It just flakes off.
Thanks for the idea Steamchick,...but I'll need to try your idea on a piece of scrap first to see how well it works. I'm quite concerned that the sodium hydroxide, no matter how diluted, will attack the aluminum part.