Brazing Bandsaw Blades cut from Coils

[Karl Loeblein]

Here are some pics of my brazing process for anyone interested in the brazing their own bandsaw blades cut from coils stock:

**Blades can be cut to link from coils using tape measure and tin snips.

First word of warning: Suggest grinding at a pretty high angle on a smooth wheel to avoid a catch.
Don't hold the blade down toward the platform or it could be grabbed if it gets caught between the wheel and platform.


First step is to grind a kerf about 3/8" so ends overlap when brazing.


Then clamp blade to a piece of angle iron or aluminum with a sharp 90 degree angle
(rounded inside angle are no good) with a small section removed brazing.


Add solder paste a a small section of silver solder ribbon that is a little wider than the blade.
Don't be stingy because it's pretty cheap per blade.


Heap blade and solder with Propane or MAPP gas torch until solder melts. It's about done when blade starts turning red.
Slowly back the heat away.


Clean up solder joint with a cheap (i.e. Harbor Freight) diamond file.


Note: I take a handheld air grinder to smooth out the joint after mounting it on my bandsaw so it runs smoothly through the guides.

That's it. Process takes about 5 minutes from start to finish.

 

[Lou Jacobs]

Karl, thanks for this clear tutorial! Standard propane torch like I use for sweating plumbing fittings?

 

[Clifton C]

Well, I seem to have all the components to practice. I have medium and hard silver solder and flux, some old blades and a short piece of aluminum angle I've been saving for years. I would assume hard solder, but sometimes my assumer is off. Any idea?

 

[Karl Loeblein]

The ribbon silver solder and flux can be found on eBay from this seller for $15.

https://www.ebay.com/itm/313464940696

Other places may carry this if you search online, but I doubt it would be much cheaper.

 

[Karl Loeblein]

Karl, thanks for this clear tutorial! Standard propane torch like I use for sweating plumbing fittings?

Standard torch for plumbing works great. Either blue (propane) or yellow (MAPP gas) tank will work but most of the time I use the yellow tank because it is slightly quicker.

 

[Don Wattenhofer]

I did that many years ago and I believe I learned the technique from a how too book that might have been Delta's "getting the most out of your bandsaw".

 

[robo hippy]

Hmm, interesting. Can't remember how my bandsaw shop does it. I thought they welded it, ground it, then annealed the joint. I would need a hands on class to do it properly, but think I would still prefer to have the shop make mine.

robo hippy

 

[Richard Coers]

I prefer MAPP. One of the reasons I think this kind of joint is successful is that the heat soaks into the steel and anneals it. Traditional blade welding localizes the heat and then an annealing cycle has to be used. We had a blade welder at my day job and it was more like magic if the annealing worked or not. When not the joint was very brittle. Could have just been me, or the guy that trained me, but I have more success silver soldering at home. I've done up to 3/4" blades . I grind the skive joint on a disc sander with a miter gage for a nice accurate angle.

 

[robo hippy]

When looking into making the Big Ugly tools, consensus was that the old MAPP torches would get things hot enough to properly melt the silver solder, but the newer ones won't. I guess they new and improved them or some thing so the newer ones don't get as hot. Do you use flux first?

robo hippy

 

[Karl Loeblein]

When looking into making the Big Ugly tools, consensus was that the old MAPP torches would get things hot enough to properly melt the silver solder, but the newer ones won't. I guess they new and improved them or some thing so the newer ones don't get as hot. Do you use flux first?

robo hippy

I can melt the ‘ribbon‘ type silver solder with a propane torch so I would expect any MAPP torch would do. The flux paste gets added to the blade kerf before inserting the ribbon solder.

 

[Tom De Winter]

I use a Smith Little Torch with oxy-acetylene. Ribbon silver solder would be a good option and I’d use it if I had any. I cut off a short piece, lay on the joint and let it suck in when the temperature is right.

 

[robo hippy]

Hmm, maybe it was for making the Big Ugly tool where I was trying to heat 5/16 thick metal hot enough to melt the ribbon. Top metal was 1/8 thick tantung. The more light weight torches might work better for bandsaw blades than for the Big Ugly tool. The only thing I really know how to use torches for is setting off fire works...

robo hippy

 

[Don Wattenhofer]

Hmm, maybe it was for making the Big Ugly tool where I was trying to heat 5/16 thick metal hot enough to melt the ribbon. Top metal was 1/8 thick tantung. The more light weight torches might work better for bandsaw blades than for the Big Ugly tool. The only thing I really know how to use torches for is setting off fire works...

robo hippy

I was thinking of how to get the point across that it isn't the flame temperature but rather the volume of heat that is needed to get the mass of metal involved up to temperature. To demonstrate the difference cut a 1/2" wide strip of steel from a steel can then using a propane torch compare how long it takes to get red hot verses a 1/2" band saw blade.

 

[Karl Loeblein]

The ribbon silver solder and flux can be found on eBay from this seller for $15.

https://www.ebay.com/itm/313464940696

Other places may carry this if you search online, but I doubt it would be much cheaper.

Current link for eBay seller with the silver solder & flux for brazing bandsaw blades. Price has risen slightly in the last two years, but that’s understandable.

Good for brazing about 40 to 80 blades.
https://www.ebay.com/itm/256003081427

Splicing jig if you don’t want to make your own:
https://www.ebay.com/itm/255895888033

 

[Doug Rasmussen]

I've brazed blades, but definitely can't do it in 5 minutes, more like 20 minutes. It's a good process to know if you need a blade on Sunday night when there are no other options than DIY.

Two saw shops local to me will weld blades, one with a crabby lady for 10 bucks while you wait and the other 12 bucks with a smile for pickup a day or so later. Both shops guarantee their welds forever against breakage at their weld and won't re-weld used blades. Neither one particularly likes to only weld, they want to sell the blade stock which is where they make their money.