shoepatcher Report post Posted November 12 (edited) On 11/10/2024 at 6:51 PM, DieselTech said: Are you using mapp gas? I don't think propane will get it hot enough to solder. Also a liquid or paste style flux will probably work better. Your feed dog is what i call a slotted feed dog. I believe they make ones that are not slotted with just a hole, not an elongated hole for the 341. Buy a new feed dog. A clone if need be. Try part# 212-25008. Quicker and less headaches. glenn Edited November 12 by shoepatcher grammar Quote Share this post Link to post Share on other sites
1hp Report post Posted November 12 nice to have extra feed dogs to experiment on. Quote Share this post Link to post Share on other sites
ElfLeather Report post Posted November 20 (edited) Late to the party, and someone's prob already mentioned but when people say "No, SILVER solder! Not silver SOLDER!" they mean high-silver brazing wire, and they mean brazing, not soldering. Traditionally this meant 40% or 45% with cadmium, but since cadmium is no buena to breathe in, you want 56% silver. As thin as you can buy it. I used to use this stuff all the time at work. If your workpiece is small, you can probably get away with a ordinary plumbing torch with mapp gas. Clean the surface down to bare metal, wash the hell out of it with degreaser and water, rough up the exact zone you want to braze with sandpaper, and brush your zone of interest with a thin layer of white or black brazing flux. The alloy will ONLY wet where there's flux. Mount your work so gravity works for you, the stuff flows like water when it melts. Bring the work zone to a dull red glow. When the flux melts clear, start feathering the flame and dab some brazing alloy onto your zone of interest. It should melt mostly from the hot flux on the workpiece, and it should leave a clean melt, not a half-melted thing sticking out. Pull the heat away, let it cool a little, and quench it in water to loosen the flux residue. If the plate is made from heat-treatable steel, this will likely ruin the heat treat. If that happens it'll be glass-hard extremely brittle, and you'll have to ask someone else about tempering it. Don't try to use "silver" plumbing solder (silver jeweler's solder is a wildcard, i don't know which alloy it is). Don't try this without the right kind of flux. The alloy won't wet the surface. Harris stay-silv white or black brazing flux is good and Harris safety-silv 56 is the alloy I use. The technical grade for the 56% silver brazing wire is AWS BAg-7, (or BAg-1, which is the grade with cadmium), and the flux is AWS FB3-A for the white or FB3-C for the black. Edited November 20 by ElfLeather Quote Share this post Link to post Share on other sites
toxo Report post Posted November 20 4 hours ago, ElfLeather said: Thanks for the info @ElfLeather. It's not an experiment I intend to repeat anytime soon. Too many variables. Worked on the dividers, didn't work on the feed dog. Being an ex fabricator/welder It's surprising I haven't had to use it before now. The mig is too handy and less faff where it can be used. Quote Share this post Link to post Share on other sites
