How to repair...

    --My drafting machine finally died. One of the two tensioning bands failed at the original join point. Would silver soldering be adequate or
should it be spot welded? The material is incredibly thin; maybe 1/4" wide, maybe .010" thick. I'm thinking if I heated it enough to hard solder it I might cause general annealing; not sure if that's good or bad. Anyone ever fixed one of these things??
--
"Steamboat Ed" Haas : Never thought I'd live to see
Hacking the Trailing Edge! : our "iron curtain" crumble...
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adequate or

1/4" wide,

it I

Anyone ever

We used to spot weld small stuff like that with a charged capacitor, adjusting the charge voltage to adjust the oomph. This lets you practise on a scrap bit before comitting yourself
AWEM
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    --Hey neat idea! Must go fiddle.. ;-)
--
"Steamboat Ed" Haas : Never thought I'd live to see
Hacking the Trailing Edge! : our "iron curtain" crumble...
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wrote:

We welders are a talented group. Now, why is it that they won't let us be in the driver's seat of this nation for a year or two? We'd figure it out, get it fixed, and probably do it cheaper.
Steve
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A friend used to have some very small silver solder, about 1/32" dia. He would cut off a very small piece, (less than an 1/8") to do delicate tasks. He would then flatten this piece with a small hammer. He cleaned the pieces to be joined, applied Silfoss flux, and then laid the tiny piece of silver solder (almost pure silver) on the joint. He would then take a small propane bottle torch and being very sensitvie heat the joint from the bottom, until the solder melted. The solder would flow into the joint... worked great.. The solder he used was much more softer than the refrigeration solder I was used to. His was, I believe, a jewelry solder. This is also a good way to mend broken band saw blades.
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Yes. What he was using is Jewelers' Hard Silver Solder. It has a much higher silver content than most general use solders. The technique he was using is called Chip Soldering. Where you place the solder chips directly into the joint.
Jewelers' Solder comes in 3 grades, Hard, Medium, and EZ (easy flow).
If you start with Hard solder, you can do at least 3 solder actions on a single piece by using progressively softer solders.
However since every time you heat solder it burns out a few alloying elements, and therefore requires a higher temp to remelt it, you can actually get a lot more solder actions on one piece. I have known jewelers who could get 4 solderings on each grade, for 12 total solderings on one piece of jewelry.
That takes very good heat control. Traditionally Batters Flux is used, but any high temp Silver Solder flux should work.
The other trick is to boil the water out of the flux without ejecting the solder chips. Again it takes good heat control.
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    --Would that be the 56% stuff? I might have some in the shop..
--
"Steamboat Ed" Haas : Never thought I'd live to see
Hacking the Trailing Edge! : our "iron curtain" crumble...
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56% silver content is still in the repair solder category. Jewelers Solder is more like 70% - 90%.
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    --Yikes! Where to get??
--
"Steamboat Ed" Haas : Never thought I'd live to see
Hacking the Trailing Edge! : our "iron curtain" crumble...
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I tend to get mine from Rio Grande. https://www.riogrande.com/home /
I used to buy from Swest before they were bought out.
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Wow, Swest was big. I am surprised they got bought out.
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It was few years back, but if I remember right, they were bought out by Stuller. Which was a pain, because they wanted a business license just to talk to me. I buy my bulk silver from Hoover & Strong now.
Btw, moving the laptop out to the shop is nice. I can read newsgroups while I'm waiting for the mill to run a pass on the power feed.
Now I just need to get heat out here other than the forge...
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My favorite dealer is Indian Jewelry Supply
http://www.ijsinc.com /
Rio Grande is OK too.
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Ed,
What kind (make-model) of drafting machine is it? I have an old one (but no scales), sitting in my office at work, looking for a home.
Ken
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    --It's a Mutoh. No sweat tho; I've got the ebay replacement together and working fine.
--
"Steamboat Ed" Haas : Never thought I'd live to see
Hacking the Trailing Edge! : our "iron curtain" crumble...
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