Replies

1. 
   hammer1 | Oct 18, 2009 02:02am | #1

   The ends of the blade need to have a good fitting scarf joint where they join. The solder or brazed material has to be ground flat. Of course, the blade has to be kept in line. It's a bit of a challenge without a specialized machine. Poor connections can result in a blade that breaks easily, thumps through the guides or doesn't run correctly. The coil blade stock is less expensive than ready made blades. Whether it's the way to go depends on what you want for blades, how many you use and how good your joining skills are.

   Beat it to fit / Paint it to match

2. 
   old saw | Nov 02, 2009 01:42pm | #2

   I think it is worth it - I've been making up my own blades for many years, and I have saved a bunch of money.  Plus there is the convenience of being able to repair a blade oneself when necessary.  Years ago I worked in a shop where I constantly used a bandsaw all day long.   There was a resistance butt welder to join blades and I learned to use it and to depend on it.  They used to tell me that prior to getting that welder, they had always silver soldered their blades.  Unfortunately they did not tell me how that was done.  :-)  Later when I no longer worked there I remembered there was this simple way to join blades without an expensive welding machine and I set out to learn it.

    Hard silver soldering, or silver brazing, is not all that difficult to learn, and it doesn't take much in the way of tools.   The most difficult part is learning to file or grind a close-fitting scarf joint on the blade ends.  Unfortunately for me no one I asked bothered to tell me that a scarf joint was necessary - I had thought one could simply butt the squared ends of the blade together and dribble solder into the joint.   Uh no, that doesn't work, and so I gave up on the idea. 

   Several years later I read about scarfing the ends, tried it, and it worked like a charm; it was in an article in FWW in the early 80's.  There was a sketch of a simple holding jig one could make from a piece of angle iron, although you can buy one.  You will need a hot, pencil tip propane or Mapp gas torch, some silver braze wire or ribbon, suitable flux, a grinder of some sort to make the scarf joint, and a single cut file to clean the finished joint. 

   The width of the scarf on each blade end should be at least 3 times the blade's thickness or more, and the angles should be complementary to each other.  I made a simple jig to hold the blade ends against the side of my bench grinder wheel for grinding the scarf.   The bare metal has to be clean and shiney bright.  If you don't have a grinder, the scarf can be done with a file.  In fact, an old man, who had been a millwright once, told me that the large mill bands that he had worked with were scarfed by hammering the ends thin after being softened in a forge fire.  

    Apply some flux paste on the ends, put the blade in your holding jig, and then snip off a tiny piece of solder wire and place it inside the joint; I use a pair of tweezers.  Heat the joint red hot with the torch flame and don't heat any more of the blade length than necessary.  When the joint turns bright cherry red to reddish orange the solder should melt and flow; you may need to press on it with something and hold it together until the solder sets - something small that won't suck the heat out of it.  I use an old screwdriver.  If you build the FWW jig, there is a pointed screw or nail to support the jont from underneath - I found that to work very well in combination with the screwdriver on top. 

   Think of it as you would a glued wood joint - you want a tight fitting joint with very little solder or "glue" in it to have the strongest joint.  Do not let the joint and its surrounding area cool too quickly or it will be brittle.  For a 1/4 inch wide blade it should still be warm to the touch after a minute or two.  Next clean off the excess solder with the file.  If the file skates off the blade itself, it has cooled too quickly and hardened.   Heat it again, but not nearly cherry red - you do not want to melt the solder - and let it cool slowly.   Try the blade on the saw. 

   If I were you, I would practice my soldering technique on some scrap or pieces of old 1/4 inch blade before I committed to a good length.  Half inch wide blades are more difficult to do than narrower stock.  For blades wider than 1/2 inch you may find you need a set of blacksmith's brazing tongs and a forge to heat them.  BTW, if you can not find silver solder, it is possible to use thin brass, but it will take more heat to melt it and you may need some tinning compound for the blade ends.  If you cannot find the proper flux, you can use a mixture of borax and boric acid made into a paste with clean rain water.   A bit of table salt added to it might help as well.   Good luck. 

1. 
   tomwalz | Nov 02, 2009 07:49pm | #3

   Hard to improve on what Oldsaw said.

    

   I would just add that there are lots of silver braze alloys in the world.   56% silver is common and easy to use but fairly weak.   50% silver is stronger.   49% with Manganese is strongest.  

   With a good, clean (oil and grease free) scarf joint any should work.   

     

1. 
   old saw | Nov 03, 2009 05:23am | #6

   Yes, it is all in the quality of the scarf - if the two ends do not fit well, no amount of solder will hold them.  I use a high temperature silver braze wire I bought at a hardware store years ago, along with a special flux.  I'm not certain what exactly is in the alloy or the proportion of silver, but the flux was mostly potassium borate and potassium fluoroborate.  The flux does not keep well for more than a few years.  I have never tried any of the low temperature silver solders or the kind that plumbers use for sweating copper pipes, but they might work - might be strong enough.

1. 
   mike4244 | Nov 04, 2009 12:20am | #11

   None of the plumbers solder or flux will work. Look up website " Stan Rubenstine Associates". They have the proper silver solders in different forms,plus the correct flux.If you have any questions they will answer you in short time.

   mike

1. 
   old saw | Nov 04, 2009 02:04am | #12

   "None of the plumbers solder or flux will work."

   Thanks.  I had a hunch those wouldn't work.

2. 
   charnwood123 | Nov 02, 2009 10:10pm | #4

   Thank you for your informative reply and taking the time to post I have found a company where I live in the United Kingdom who are prepared to sell excess stock at fraction of the retail price
   Therefore purchasing blades that are oversize and either welding them myself or paying for them to be welded becomes a viable propositionregards Charnwood

1. 
   old saw | Nov 03, 2009 05:47am | #8

   You are quite welcome.  BTW, save the left-over pieces of blade that are too short to use on your machine - they are good for all sorts of things.   You can make scrapers and small knives from them or use them for bow saw blades.  Another use it to bind eight or ten short lengths together side by side to make a heavy duty wood rasp.

3. 
   Eef | Nov 03, 2009 12:31am | #5

   o. saw, just wanted to say that your bandsaw blade soldering instructions is a very good read, very enjoyable.
   thanks,
   eef

1. 
   old saw | Nov 03, 2009 05:25am | #7

   Thank-you very much.

3. 
   old saw | Nov 03, 2009 03:22pm | #9

   Here is a link to an article showing a brazing jig similar to what I use; you might find it helpful.

   http://wiki.owwm.com/BandsawBladeSoldering.ashx

1. 
   charnwood123 | Nov 03, 2009 10:13pm | #10

   Again many thanks for the excellent information you have provided and the level of detail contained within your posts

    

   kind regards Charnwood