Fixing broken bandsaw blades

I'd say that grinding at an angle is recommended. I think it's called a "scarf". Your alignment jig needs only to hold the two ends together "out in space" so the heat won't sink away too fast. I use a silver solder that melts at about 1200° F. I align the ends, overlapping at the scarf by, maybe 1/4" and sprung slightly so the ends lie firmly together. I cut about 1/4" of silver solder off the roll and smash it flat, so it's about 1/32" thick. Do this on a clean plate so you don't add any crud to the solder. Add some brazing flux between the ends (too much is better than too little), and poke the piece of solder in between the ends. Heat gently with a torch. Unless your blades are much wider than 1/2", a propane torch will do. Just as color comes (in a dimly lit area), solder melts and is squeezed as joint pulls together, back torch off and let cool.

Pete Stanaitis

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steamer wrote:

I believe Ernie had posted a detailed TIG brazing procedure for bandsaw blades some time ago. You might try searching for it. If I run across it I'll repost it.

Grinding at an angle is the way to go if you're going to silver-braze the blades, which is the traditional method. I've been using it for over 30 years and I much prefer it to home-welded blades. The brazed joint is much stronger than the parent metal and the finished joint is smooth.

However, I don't doubt that someone who's really good at TIG can do a fine job. It's just that it isn't necessary.

-- Ed Huntress

The technique was TIG brazing, not welding.

I'm not sure about that. I think Ernie welds them. See

A friend of mine found out I had a blade welder and asked me to make some specials for him from his stock. I told him I didn't have much experience at blade welding, but I would give it a go. I took one of my old ones and made the joint crooked intensionally, and then welded it so that you couldn't uncoil the blade. When I handed it to him, he made a face, but was trying to be polite. I told him that little bump wouldn't be too noticeable. :-)

Great fun.

I've certainly TIGged them sucessfully. 0.040" tungsten and small (0.030" ?) SS MIG wire seems to work.

Pete

Dunno, that doesn't seem to be the thread I recall. Perhaps I'm confusing a TIG brazing and a TIG blade welding thread.

Ernie was recommending welding the blades with ER80-S-B2. My (limited) experience has been to get as small a filler rod as you can find. I got some 0.045 and would like it thinner.

Here are a couple of pictures of a jig that I made a few years ago:

I made mine out of a 18" length of scrap 3" channel with two 6" lengths of 1& 1/2" L bolted to the web, 1/4" above the flange with a couple cap screws to act as clamping screws. Then I cut a 1" gap in the flange midway between the clamping pieces to act as a working area for the propane torch. Gerry :-)} London, Canada

To do the scarf, I put the two ends together, apply vice grip and hit the bench grinder to give about a 30 deg. bevel. Doing both ends together will ensure that the bevel is close to the same on both ends. Don't worry about matching teeth. Gerry :-)} London, Canada

--Very neat; very simple. Thanks for the photos! Mine's a little more complex; will post photos tomorrow.

Thanks, I'll take a look.

Bob