Brazing a bandsaw blade

I just repaired one today. I had tried to cut too sharp curve and
my brazed blade broke. Re-brazing was easy. Almost too easy.

The braze is likely to be the weak point but still pretty strong
and repairable.

The break in mine was not at the weld, but a few inches from the weld.

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

... could be metal fatigue. Wheel diameter is relevant,
as is tempering.

Keep at it. I am.

I use my MIG to weld my broken blades all the time, I grind the ends down a little, clamp the blade to a piece of scrap with a slight gap between the ends then carefully fill the gap with weld. I then grind it flat. I haven’t had a weld break yet and I’m no expert welder!

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It sounds like you “soldered” the blade, not “braised” it. If the silver solder ran easily into the joint, it was a soft silver solder which will not hold up A brazing alloy contains at least 50% silver while silver solder is around <10% silver.

Blades are only 10 – 15$ Order a couple spare.

-- A positive attitude will take you much further than positive thinking ever will.

MrRon – I use Harris 45 or 54(?) silver solder 1/32 diameter or the shim stock style to build and repair the majority of my blades. The initial cost of silver solder is expensive but it only takes a small amount and seems to work well on my 1/4 and 3/8 blades for wood. I have NOT tried these blades on metal as I work in a local tool shop and I “sneak” my metal sawing in when I get off work. I have tried to use a band saw blade welder and to tig weld but by far the easiest way I have found to repair / build blades for me is with a propane torch and silver solder

Mr. Ron: I got this silver solder originally for brazing stainless, and it works well for that if the metal is not too massive (which can make sufficient heating difficult). It is Harris “Safety Silv” 56, (cadmium free), 1/16” diameter. That’s 56% silver. I think it flows well in blade brazing because the small metal cross section heats up to red hot very quickly. I also use MAPP gas, which burns hotter than straight propane. The “silver brazing alloy” is very expensive, but a little goes a long way. My tapered overlap of the blade ends (like a scarf joint) was about 1/4” long.

Airspeed: I haven’t tried MIG, and if I do so, it will be with trepidation. That’s because I’m not skilled at welding very thin steels. They tend to burn up on me, so that I get a hole rather than a weld.

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

I tried to tig using 6 to 10 amps – I had no filler rod to add that was below .035 in diameter. If I had had filler rod that was say .010 to .012 I might have had some success. I spent more time grinding off the excess weld that the time it took me to silver solder the other blades. I have NO experience with mig welding so I am completely new to that subject. The blade welder on the band saw at work is really set up for heavier blades that I am using at home. True it does have settings for the smaller blades but it makes a HUGE deposit of metal when it is done requiring me to do a lot of grinding when finished.

Runswithsissors – I am using the same brand of wire except it has 45% silver – this is what my employer buys ( I can purchase it thru them at a discount) your alloy IS a better alloy for this application – possibly next time Ill give it a try – thanks !

Sounds like soldering is a much easier process! I’ll have to try that next time I break a blade. I have silver solder, heck, I may even snap an old blade to see how it works! Thanks for posting your method.

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If the blade breaks at the joint, it’s because the joint was contaminated with body oil, or wrong flux and brazing material or too much or too little heat. If it breaks beyond the joint, it’s because it hasn’t been annealed after brazing. The joint is brittle and the area has to be annealed by passing the torch over the joint a few times, somewhere around 600°f and allowd to cool slowly.

Good to hear that. Re welded band saw blades easily break. It’s welded part is its weakest point.

-- "someone has to be wounded for others to be saved, someone has to sacrifice for others to feel happiness, someone has to die so others could live"

Lots of info here. I immediately thought of a metallurgist that worked in the same dept with me. He defined a weld as a series of continous flaws joing 2 pieces of sound metal. Always remember that.