Thread: repairing/making bandsaw blades - HELP

Mike, I eventually found it easier to get the blades made to order, less headache that way.

Don't put the rod on the blade and then heat, or it's not the way I have always done it. Prepare the joint and flux just between the two on the join faces, the band face does not need flux but it is most probably impossible to avoid in reality. Heat the joint until the flux goes clear like water and THEN add filler and only a small amount of filler and the filler should run into the fluxed area. To give you some idea, it is possible to flux the thread of a bolt, position it vertically and heat, when the flux goes clear apply the filler to the bottom of the bolt and the filler will travel up the thread and stop when it runs out of flux.

I taper the ends of the blade for about 6mm and apply flux to both surfaces and overlap. Here is the difference, I use ribbon silver solder. Cut a small section of the silver solder the same size as the joint and apply heat until the solder runs and let cool. Haven't had a problem with this method. Can't remember what percentage of the silver solder is, sorry. Is it possible to hammer the rod flat to make some "ribbon" solder?

Jim

What percentage of silver is in the solder? Some "silver solders" are only 2% silver and are mainly used for plumbing work. Bandsaws need a higher percentage of silver which melts at a lower temperature. You should be able to bevel the ends of the blade, bring them together, heat to dull red, add a small quantity of flux and bring the rod to the join. If you heat the rod and dip it into the flux the flux will adhere to the rod and that saves you a step in the process. Or you can buy flux-coated rods.
What sort of clamp are you using to hold the blade ends together? Is the clamp acting as a "heatsink" and sucking the heat out of the blade? What sort of flame are you using? Is it hot enough? You need the heat to flow back along the blade about 50mm either side of the join and the beveled ends need to be clean and both need to be at the right temperature. That can be harder to do than it looks. Sometimes we have to heat both sides of the join to get the solder to flow using MAP gas.
Good luck. Once you get it right, it's simple. Getting it right is the part that tales practice!

45% sticks and recommended flux. thanks for the tips everyone. Got it sorted now. Bought a decent MAP torch. Did 8 blades in 40 mins. only another 50 or so to do.

Hi Pat. i agree but a got a heap of old but unused blades - all to long for my Laguna. Enough to see me out i reckon.

You also need to anneal the blade on either side of the join. Just heat the blade about 50mm either side of the join, most heat near the join then gradually diminishing as you move away. This reduces the hardness of the band and reduces cracking at the join. Also....Cleanliness is the key to a good brazed join. No rust or contamination of the metal and all will be well (don't grind the blade edges and let them sit overnight in a damp shed so they go rusty! Grind, then braze while things are clean!) provided you get the temperature right, (not too hot, not too cool) sort of like my grandmother making scones, got to have the oven temperature just right!