From: djb@invalid.com   
      
   On 20/02/2026 19:19, Bob La Londe wrote:   
   > On 2/17/2026 8:52 PM, Snag wrote:   
   >>    I'm going to try my hand at brazing new carbide on some chipped   
   >> and worn boring bars for my mill . I have 3 choices for heat source ,   
   >> O/A , TIG , or my induction heater . I also have a couple of choices   
   >> for braze filler , phosphor bronze TIG filler , regular brazing rod ,   
   >> and silver solder if I can find mine . I also have some brass wire ,   
   >> composition unknown and a few sticks of silphos , though I don't know   
   >> if that will stick to steel . I also have both borax and regular   
   >> brazing flux .   
   >>   
   >>   The plan is to heat and remove the old/broken insert , apply flux   
   >> and a thin piece of brazing filler topped with a new carbide piece ,   
   >> and heat to brazing temp . After watching a couple of youtube videos   
   >> it looks like I may need to hold the new carbide in place as it   
   >> heats/ cools , I'll probably use a piece of SS TIG filler for that .   
   >>   
   >>    I just realized that I can replace the carbide teeth on the face   
   >> mill that came with my milling machine . I tried to sharpen the   
   >> cutters on the lathe , turned out less than optimum . If I do that   
   >> I'll use the indexing device I built for sharpening end mills to   
   >> sharpen them . Might try that to even them up , might turn out I   
   >> don't need to replace them right away .   
   >>   
   >>   Thoughts on heat source and filler selections ?   
   >   
   >   
   > A quick read tells me silver solder 45% silver or higher is considered   
   > "best".   
   >   
   > Silfos (typically 15) is for copper to copper or copper to bronze.  I   
   > have a couple pieces I used for soldering copper tube on an AC unit.   
   > Silfos is nice for copper as it is supposed to be self fluxing, making   
   > out of position work easier in theory.  In reality I only got good   
   > joints on the bench.   
   >   
   > Brass can work, but it doesn't stick to the carbide as well as silver.   
   >   
   > I have a small section of 45% silver solder around somewhere and I can   
   > tell you it was expensive.  I bought it at the a local welding store,   
   > the better one, that doesn't usually gouge me.  It was NOT good enough   
   > for repairing band saw blades.  But there should be no flex in your   
   > carbide to steel connection.  If you want it you know how to reach me,   
   > to remind me of your address.  (If I can find it.)   
   >   
   > There are light fluxes and dark fluxes, and I think those with boron   
   > (black brazing flux) is best, but borax might be a poor man's   
   > alternative.  They use borax at forging temperatures afterall, (and   
   > for some heat treating operations) so it probably won't burn off.   
   >   
   > Some I recalled, some I got from an old This Old Tony Video, and some   
   > I double checked using Goggle's AI search function.   
   >   
   >   
   >   
      
   Sounds like to old go to Easyflo no2 at about 50% would do it or its   
   Cadmium free alternative at about 55%. I have some in various sizes and   
   it will roll out to a thin strip if you have a rolling mill although if   
   required really thin it'll need annealing and I've used it for this type   
   of job where I wanted a thin shim of solder in place in the joint.   
      
   I haven't tried to use it to repair a broken bandsaw blade but have read   
   that it should be suitable if a scarf joint is used.   
      
   I have suitable flux for use with the silver solder for tool tips and   
   stainless steel.   
      
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