August 7, 2014
Some things simply can’t be replaced. That’s when repair welding really comes in handy.
My father-in-law, Bob, is a Vietnam vet. He was 18 when he and several friends enlisted for war. He was the only one of the group to return. I can’t imagine the things he experienced. I’ve always been impressed by the fact that despite the mental and physical toll that part of his life took on him, he’s been a faithful husband, a loving father, and a skilled tradesman for 40 years.
When he returned to the States, he brought with him a set of metal stools. Not long after his return, he married Linda, and the stools were used as their first dining chairs. Over the years a few had been damaged or lost, so now there are only two left. One had a crack forming around the perimeter where the top was attached to the “bowl,” and he asked me if I could take a look at it and possibly repair it. Heck yeah, I’ll give it a shot.
First thing I noticed was that it was kind of an odd metal, probably a type of brass. I didn’t have the right oxyacetylene torch setup or filler/flux to braze or solder it in a traditional method, so I decided to TIG braze it with SiB. Silicon bronze is kind of my go-to filler for oddball stuff.
The crack that had formed showed that it had been soldered together, so just grinding the crack and TIG brazing over it wouldn’t work. The old solder was still in the joint, and it would have contaminated the braze.
So, next I split the top of the stool from the base, which wasn’t hard. Years of use had weakened the bond. I also marked how the top was oriented on the base to ensure a perfect fit when I reattached it. Once the top and bottom were separated, I used a stiff wire wheel to remove the old solder and clean the surrounding base metal. Any surface grime, oxidation, or old filler would give me grief once the brazing started.
Once it was clean, I placed the seat back onto the base. With the correct orientation it fit like a glove, and I used a vise grip locking clamp to hold it in place. Now it was time to melt metal.
TIG brazing with SiB can be done on AC or DC. Typically, I like using DC (electrode negative, just like steel), but I wanted all the cleaning I could get, so I tried this project with AC. And it worked very well. After tacking the top in several areas, I skipped around the stool, brazing short 2-in. to 3-in. sections at a time. This kept the heat down and even. The pool stayed nice and calm, it flowed relatively smoothly, and overall it turned out a nice bead.
And Bob was happy with the finished product. An heirloom from ‘Nam was saved, and is again put to use every day. Another reason I love repair welding: fixing something otherwise irreplaceable.