Can NaF be used as a flux?

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Can NaF be used as a flux for steel and aluminum welding, since the fluoride ion is highly reducing?
Reply:I'd expect NaF to behave a lot like NaCl on steel and make lots of rust.  Of course, I got a C in chemistry. So I could be wrong Dynasty200DX w/coolmate1MM210MM VintageESAB miniarc161ltsLincoln AC225Victor O/A, Smith AW1ACutmaster 81IR 2475N7.5FPRage3Jancy USA1019" SBAEAD-200LE
Reply:Well, you do need a flux to provide a reducing enviroment, so the heat from the electrode doesn't cause it to rust. And, I just found it is a component of Aufhauser Flux-17, used for stainless steel welding. A good flux should be able to take the place of shielding gas, so I suppose if a M/TGAW welder runs out of shielding gas, they could just fill the joint with salt to provide a nice slag layer to protect the joint from oxidation, which would sort of convert M/TGAW to SAW.Last edited by Protoman2050; 07-16-2010 at 01:12 AM.
Reply:Protoman,  yes NaF can be used to flux aluminum.  I know it's one of several ingredients used in fluxes for furnace brazing of aluminum radiators.  There are also some AlNaF (cryolite) that are used to flux aluminum for brazing.I couple warnings.  #1  You should absolutely look at MSDS sheets and research these chemicals.  Some are caustic and some are potential toxins or carcinogens.  Not saying you can't use them.  Just suggesting you learn as much as possible about them before you purchase and work with them.#2  From past experience.  Brazing aluminum with Fluorine-containing fluxes needs good post-brazing cleanup procedures.  If you leave flux residue behind, some of that residue will contain HF, hydrofluoric acid.  In the case of an aluminum radiator, when you add coolant(water) the HF eats holes in the radiator.  A very thorough rinse immediately following brazing prevents this problem.  Keep this in mind for whatever projects you're planning...Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Originally Posted by A_DAB_will_doProtoman,  yes NaF can be used to flux aluminum.  I know it's one of several ingredients used in fluxes for furnace brazing of aluminum radiators.  There are also some AlNaF (cryolite) that are used to flux aluminum for brazing.I couple warnings.  #1  You should absolutely look at MSDS sheets and research these chemicals.  Some are caustic and some are potential toxins or carcinogens.  Not saying you can't use them.  Just suggesting you learn as much as possible about them before you purchase and work with them.#2  From past experience.  Brazing aluminum with Fluorine-containing fluxes needs good post-brazing cleanup procedures.  If you leave flux residue behind, some of that residue will contain HF, hydrofluoric acid.  In the case of an aluminum radiator, when you add coolant(water) the HF eats holes in the radiator.  A very thorough rinse immediately following brazing prevents this problem.  Keep this in mind for whatever projects you're planning...
Reply:Sodium Chloride is not enough of a flux for aluminum in itself. Potassium Chloride, Lithium Flouride and Lithium Chloride are needed. The higher the active temperature, the greater the ratio of Potassium to Sodium Chlorides. It was common to use these mixtures with carbon arc welding of aluminum.....so there is nothing new here.
Reply:Originally Posted by makoman1860Sodium Chloride is not enough of a flux for aluminum in itself. Potassium Chloride, Lithium Flouride and Lithium Chloride are needed. The higher the active temperature, the greater the ratio of Potassium to Sodium Chlorides. It was common to use these mixtures with carbon arc welding of aluminum.....so there is nothing new here.
Reply:See definitions 1 and 5a - 5c below.  Seems self explanatory.  Pardon my earlier posting if it seemed I was talking down to you.  Your profile says you're 19 and a college student.  I didn't know squat about chemistry when I was 19, so I assumed you don't either.FLUX:/flʌks/  Show Spelled[fluhks]  Show IPA –noun 1. a flowing or flow. 2. the flowing in of the tide. 3. continuous change, passage, or movement: His political views are in a state of flux. 4. Physics . a. the rate of flow of fluid, particles, or energy. b. a quantity expressing the strength of a field of force in a given area. 5. Chemistry,  Metallurgy . a. a substance used to refine metals by combining with impurities to form a molten mixture that can be readily removed. b. a substance used to remove oxides from and prevent further oxidation of fused metal, as in soldering or hot-dip coating. c. (in the refining of scrap or other metal) a salt or mixture of salts that combines with nonmetallic impurities, causing them to float or coagulate. 6. fusion.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Originally Posted by A_DAB_will_doSee definitions 1 and 5a - 5c below.  Seems self explanatory.  Pardon my earlier posting if it seemed I was talking down to you.  Your profile says you're 19 and a college student.  I didn't know squat about chemistry when I was 19, so I assumed you don't either.FLUX:/flʌks/  Show Spelled[fluhks]  Show IPA –noun 1. a flowing or flow. 2. the flowing in of the tide. 3. continuous change, passage, or movement: His political views are in a state of flux. 4. Physics . a. the rate of flow of fluid, particles, or energy. b. a quantity expressing the strength of a field of force in a given area. 5. Chemistry,  Metallurgy . a. a substance used to refine metals by combining with impurities to form a molten mixture that can be readily removed. b. a substance used to remove oxides from and prevent further oxidation of fused metal, as in soldering or hot-dip coating. c. (in the refining of scrap or other metal) a salt or mixture of salts that combines with nonmetallic impurities, causing them to float or coagulate. 6. fusion.
Reply:In the case of aluminum its also stirred into the puddle to absorb the atmospheric nitrogen from the weld pool as the flux floats to the surface. Thats the primary reason fluxed aluminum welds have higher density than non fluxed welds and thus tend to be more sound, leak and fatigue resistant.
Reply:Originally Posted by makoman1860In the case of aluminum its also stirred into the puddle to absorb the atmospheric nitrogen from the weld pool as the flux floats to the surface. Thats the primary reason fluxed aluminum welds have higher density than non fluxed welds and thus tend to be more sound, leak and fatigue resistant.
Reply:Originally Posted by Protoman2050So, you use TIG and a flux coated filler rod?