Anticept Posted September 4, 2016 Report Share Posted September 4, 2016 We had some gouges and cracks in our aluminium piping welded before on our CTs. Well, I was replacing a leaky segment of hose and it looked like someone had tried this before with some seriously sharp instruments (aircraft was purchased used, and just before it was bought, the hose change was done), leaving a really deep gouge. I found out our welder guy is out on a job for at least a week in another city. And, where this pipe was located, I would have to remove a bunch of stuff to get to the clamps. We were considering using JB weld, but it's not exactly a kosher thing. Maybe it would work fine, but I really don't like using it in aircraft because there are better things. I was searching around for ways of fixing cracks that might be adaptable to fixing gouges, and I saw something that I hadn't thought about in a while. Brazing! Now disclaimer: I SUCK at welding. I was probably the slowest person in my class and never got past the basics (granted, we were using oxy-acetaline welding, which I understand is very hard, but still). I wasn't sure how this would turn out. Ran to the store, grabbed some aluminum brazing rod, a propane torch, flux, and came back. Had water ready in case I set something on fire! . (actually aluminum brazing needs to be quenched to draw out and help remove the flux, but anyways) Couple of youtube videos later, I used a wire wheel to clean the area, threw on flux, lit the torch and went to work. Because brazing uses a lower heat, I didn't need to remove anything from the aircraft, I just had to make sure I didn't melt anything nearby, so I strung up hoses and such out of the way and keep the flame at a focused point. First try was meh. Filed most of it away. Tried again... not bad. Can still see some of the pitting from the gouge. Third try... CRAP too much heat and a bunch of my filler ran right down the pipe and onto the floor. Applied solder wick to soak up the aluminium and start over. Fourth try... ohhhh that's almost got it! Little more heat, couple light touches, and some filing... wow that's the best hot metal job I've ever done larger than electronics! Saw a couple more gouges on the other pipe and thought "I'll try it". Nailed it first try! Photos: First photo is the first job I did. I just noticed I didn't wipe off the shavings but anyways, it's passable. I didn't measure the first one with the caliper before I got to work, and I wish I did, it would have been a great way to make sure I don't dig into the pipe, but it's less than a hundredth difference than measuring 90 degrees rotated, so it should be pretty good! Second one is the second job. You can slightly see where it's just a little built up. I did measure that one before I started. When I was finished, I had increased the diameter by less than 2 hundredths of an inch. Both of these are quite smooth to the touch. I'll hit them with emery cloth before closing up, but it should turn out pretty darn nice! Total cost came to about $50, and the torch I can use for other projects too! Link to comment Share on other sites More sharing options...
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