Help soldering broken bandsaw blade

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On 06/11/2010 02:09 PM, Leon wrote:

Excellent idea. Where on the lawyers should we drill? I'm guessing heart area, plenty of room where the heart should be.
techomaNge ---------------------------------------------------
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Comrade technomaNge wrote:

Forget their skull. Too thick for a rivet. Maybe a 'blind' rivet? ;-)
--
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have a DD214, and a honorable discharge.
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http://www.woodcraft.com/Product/2004491/8461/WoodRiver-Deluxe-Bandsaw-Blade-Brazing-Kit.aspx
No, they are not. Are they being serious? That little torch is a joke. I have a couple and they will not heat anything unless it is very small. I would not be surprised if the solder joint as demonstrated were rather poor. The saw blade is going to conduct the heat away from the joint faster than that torch will heat it even if you *can* keep it lit :-) Note that the picture of the final result in the video was not seen well, if at all.
OTOH I wonder if using one of these pastes would be an option. I like the concept of precise application to the joint:
http://www.riogrande.com/MemberArea/ProductPage.aspx?assetnameP3053&page=GRID&category%7ccategory_root%7c126=Soldering+Equipment+and+Supplies&category%7ccat_4428%7c4440 ºse+Metal
Has anyone used them?
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Michael Koblic,
Campbell River, BC
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I have silver brazed ( often called silver soldering ) numerous things using small propane torches. Propane is hot enough. It is no problem to silver braze bandsaw blades using silver braze. I have done it. Silver brazing larger objects takes some thought. Insulating fire bricks ( IFB ) are useful. You can take some IFB's and build a little corner that keeps the heat from being conducted away. Silver braze flows at dull red heat.
Dan
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I have purchased boxes of a half dozen alloys of silver solder. Some are vary hard and require a hotter flame, others flexible and a lower flame.
Martin
Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net "Our Republic and the Press will Rise or Fall Together": Joseph Pulitzer TSRA: Endowed; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal. NRA Second Amendment Task Force Charter Charter Founder IHMSA and NRA Metallic Silhouette maker & member. http://lufkinced.com /
On 6/11/2010 9:12 PM, snipped-for-privacy@krl.org wrote:

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Silver soldering is sometimes referred to as hard soldering.
It's become more confusing because old style rosin core electronics soldering is going leadless and slowly replacing the lead in lead/tin solder with a percentage of silver. When I used to hard solder large stainless steel vacuum components to copper and brass fittings, we called it hard soldering and it was the "hard" high silver content solder that came in long thin rods like brazing rods and required oxy/ecetylene to bring up to useful temps. Of course I'm talking heavy metal mass, not thin saw blades. Bernzomatic torches may be enough for thin saw blades. The key is the flux. That Sta-Silv flux is the best. Very forgiving of wide range of temps, even severe overheating.
nb
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On 6/12/2010 8:43 PM, notbob wrote:
(...)

The black 'high temperature' stuff rather than the white stuff, yes?
--Winston
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The black is primarily for stainless steel, but we used both interchangably. If I were buying only one for general use, I'd go with the black.
The stuff is water soluble, so it will eventually dry out and become crusted over in the container, even completely dry out. Even new jars sometimes have a crystaline crust on the top. Not to worry. Just add water and remix. Its normal consistancy is a paste, about right to put on with a simple acid brush or small spatula knife. Don't be afraid to lay it on thick. Better too much than too little.
When the joint is hot enough (dull red), the flux will bubble and boil and then become like warm honey, flowing everywhere and filling and whetting the joint. Add the solder to the edge of the joint and let it flow into the joint. If it doesn't flow into the joint, it isn't hot enough or you used too little flux. Try and use only as much solder as needed. Too much and it will flow out the bottom and drip and you will end up having to grind down the blade so it will fit in the guides.
Water will clean up the post solder flux crust. A good stainless steel brush, the fine ones that look like a tooth brush or a small wheel is good to dress it all up.
nb
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On 6/13/2010 7:44 AM, notbob wrote:

Excellent. Thanks!
--Winston
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snip---

http://www.woodcraft.com/Product/2004491/8461/WoodRiver-Deluxe-Bandsaw-Blade-Brazing-Kit.aspx
That's your mistake. You don't "think" you need the 'real' stuff.
You do.
Lead free solder has no tensile strength to speak of. It doesn't come close to resembling silver solder, even if it *is* silver bearing solder.
Get the 'real' stuff and enjoy success, although you must have a greater lap area if you don't want to experience joint failure.
Harold
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Amen to that!
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Michael Koblic,
Campbell River, BC
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On 6/10/2010 6:53 PM, Lloyd E. Sponenburgh wrote:

Heh! I asked Ernie about reassembling my 10" chef's knife with *Real* silver solder. He advised the use of the *barely* silver solder rather than the real stuff because of possible temper loss.
Ergo, I figured that my Oatey 5% lead-free, cadmium-free would be plenty good for bandsaw blades.
Now I'm confused. :)
Relurking.
--Winston
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Plumbing solder is a "soft solder". It's designed to melt at low temperatures, is brittle when frozen, and is NOT designed to be structural in any sense -- it's job is to seal a joint well against leakage when sweated properly.
Your knife repair would have been better served by making the repair with a good hard solder, then re-hardening and re-tempering the blade.
LLoyd
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On 6/11/2010 4:25 AM, Lloyd E. Sponenburgh wrote:

Yup. That makes sense. Thanks!
--Winston
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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
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On 6/10/2010 7:58 PM, Artemus wrote:
(...)

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
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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
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Just thought I'd throw this in: I wouldn't even attempt to weld/solder a NEW blade, much less a broken one.. WHY did it break? Old? Bound up? Bad weld? If any of the above, I wouldn't reuse the blade anyway.. I buy good blades for less than $15 each (105") and if it's dull, bent or whatever, it gets recycled.. Not worth the few bucks I might save to take a chance on a bad joint popping loose and ruining the work or a body part, IMHO..

mac
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On 6/11/2010 2:36 AM, mac davis wrote:

Perhaps he cut it deliberately in order to make an inside cut-this is commonplace in metalworking and many band saws intended for that purpose have a blade welder attached.

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wrote:

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.
--
Ned Simmons

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