Hey Norman, Although I'm NOT a welding/brazing expert, I have several ideas as to why things may not have gone well for you...
You mentioned that the tubing you were brazing had steel in it. I'm 99% sure that you can not braze steel together. If the steel tube were coated with copper, brass or some other non-ferrous material, then you might have some luck brazing the two together. Lastly, if a non-ferrous metal was present, you may just need to use a brush on flux(comes in a paste form), in addition to the flux that you said was built into the brazing rods. I'm guessing that the steel was not allowing you to get the joint you desired. Just my two cents...(note the non-ferrous pun---intended!! LOL). Dave D. ----- Original Message ----- From: Norman James To: rctankcombat@googlegroups.com Sent: Sunday, June 17, 2012 3:35 PM Subject: [TANKS] Brazing, Round 1. AKA Oooo! Glow-ey Hot Stuff! First go at it. Given large coiled sections of brakeline are cheaper, the working medium is a 25 foot section of 5/16ths coated steel brakeline from Auto-zone: costing a grand total of some $20. While in lengths, it’s fairly flexible, I hacked off a ~4 inch and ~2 inch chunk to test with. The brass brazing rods were flux coated, so I didn’t bother with fluxing the joint, but I did grind off the anti-corrosion coating to get down to the base metal with some emery paper. Also, a cut-off wheel mounted in a hand drill was very useful for fish-mouthing the end of the test piece for a nice, clean fit. Note to self: Buy one of those sparky things. Matches don’t work well for lighting torches. Heating up was fairly straightforward, getting the metal a nice glowing orangy-red. And… That’s about where the easy bits ended. The brass rod melted down easy enough, but instead of nicely slipping into the joint (like when working plumbing joints), it kind of globbed up, and dripped off in useless blobs. Using plyers, I flipped it over and blobbed some on the other side with much the same results. I then attempted to overheat the joint, to try and (maybe) melt the blobs soft enough to run into the joint, but nothing doing: the torch just doesn’t look to have the heat to get the thing done. Letting it cool, the joint did appear to hold, meaning there must have been SOME adhesion there, despite the joint resembling a gold version of something I might have blown out of my nose. Simple hand torquing was able to snap the joint relatively easily. Conclusion: More head scratching, and perhaps try something with a melting temp less than 1600 degrees. I found some good alloy brazing rods at a local Ferguson’s with 15% silver content, and a working temp of “only” 480 degrees, so I’ll be giving that a try next. (Yes, I have a much better camera, but it was AWOL. So I used the computer's Logitech chat camera for the pics. Better quality next time) -- You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat+unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -- You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat+unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat
