Help soldering broken bandsaw blade

I'm pretty sure they needed to be welded.

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Never having done that, I feel qualified to advise that this guy *has* done that:

--Winston

I've only welded blades, not brazed them, but I'm going to guess the blade is cooling fast enough to quench it, making it brittle. After you've made the joint remove it from your jig, shine it up with sandpaper, then heat it gently by waving your torch flame around 'til the steel turns blue. You've tempered the steel enough that it should no longer be brittle.

Well, I'll be. Learn something new, every day. In college, we learned to weld them.

Winston fired this volley in news: snipped-for-privacy@news2.newsguy.com:

Winston! Winston... Winston...

First of all, get some 'real' silver solder -- the stuff you buy in the Forney section of an ACE hardware, or at a welding shop. Second, be prepared to see the metal red before the solder will flow. The Oatey

LLoyd

Silver solder (low silver content) or silver braze (high silver content)?

Wes

-- "Additionally as a security officer, I carry a gun to protect government officials but my life isn't worth protecting at home in their eyes." Dick Anthony Heller

IIRC We always welded them and then did some annealing process to soften the weld so it wasn't brittle by giving shots or current after the weld and grind. Been a long time since then...LOL

"Ned Simmons" wrote in message news: snipped-for-privacy@4ax.com... I've only welded blades, not brazed them, but I'm going to guess the blade is cooling fast enough to quench it, making it brittle. After you've made the joint remove it from your jig, shine it up with sandpaper, then heat it gently by waving your torch flame around 'til the steel turns blue. You've tempered the steel enough that it should no longer be brittle.

Aha! Thanks Winston, that's a nice site. He's using 1/2" on a .035 blade so 3/8" on my .025 ought to be in the ballpark. Now to figure out how to do it - the Dremels out for sure. I've give it a shot on the grinder or beltsander. Art

Ill come in here, Ive silver brazed my band saw lades for 40 yrs. as linked, the scarf joint needs to be minimum 3/8ths in long, you do this scarfing on the top wheel of a band sander set up vertically. Jig as also described, but bend the lower blade end up a little and he top blade down a little. You need to use a 50% if you can get it silver solder in foil form, 5 to 10/1000 in thick. cut a piece exactly to size, place between the 2 blade ends. mx up some easyflo flux paste preferrably s/steel grade, apply arround the joint area. heat gently till the flux goes clear, continue to heat till the joint goes a dull red under the flux and the silver solder flows to wet the scarf area. allow to cool clowly. Remove from jig, fftle up and grind both sides of blade so that the thickness is the same overall, as you said .025 thick. dont over tension the saw blade. Hope this helps. Ted. Dorset UK.

It is soldering and not brazing that I'm trying to do so I don't *think* I need the 'real' stuff. I'm attempting to do what these guys are doing without buying their package.

If you don't have foil, a clean hammer face and anvil surface can make some foil for you with a blow or two. :)

Wes

That's kind of what I was thinking to make the scarfs. Thanks. I don't have an OE torch. Can I use propane with the 50% silver solder? Mapp? Mapp/oxy? Art

Heh! I asked Ernie about reassembling my 10" chef's knife with

Ergo, I figured that my Oatey 5% lead-free, cadmium-free would be plenty good for bandsaw blades.

Now I'm confused. :)

Relurking.

--Winston

:Xns9D93DEAA4F54Blloydspmindspringcom@216.168.3.70...

Lloyd is right. You're using a soft solder and it=92ll never hold for this job. The real silver solder that you need is a hard solder and melts at a brazing temperature. Usually you use oxy-acetylene for silver soldering. You just have the wrong tools to do this job properly. See:

You can count on it. True silver solder is not gonna melt with that joke kit. At the very least you will probably need propylene fuel, if not oxy/acetylene. Quit clowning around and invest in a welder.

For a piece that small your propane torch should work . Dad silversoldered that way - though not bandsaw blades . Bigger pieces he put on mom's gas range plus the torch .

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As Lloyd and Ted mentioned, the higher silver content solder (ca. 45-50%) is probably what you really want.

Beware though!

Compatible flux is critical. Match the flux to your solder WRT temperature or be very frustrated! DAMHIKT

--Winston

You CAN silver solder band saw blades, very well, with a propane torch and hard silver solder. Been there, done that with never a break. You don't have to weld them.

CP

PS: I have only done it up to 1/2".

This is the best flux for silver solder. You need the Stay-Silv white. Note the temps. A propane torch should get you there. Still better off with the welder. Good luck.

nb