Silver solder technique

[Dan Schultz]

There was a day when I could MIG-weld pin holes in beer cans!

Regrettably, you and I weren't acquainted during those days - as I had a considerable backlog of pin-holed beer cans that required those services.

[roweenie]

Dan, I hope you weren't welding up those pinholes while there was still beer in the cans (unless it was Rheingold, and then who cares?)

The solder I'm using is 35% silver, and like you Wade, I don't do enough of it to feel all that confident, especially a tricky joint like this.

Dan, the lathe idea is an excellent one. I dont have one, but if I did, I'd certainly give it a try. (Someday I'm going to break down and get one - I've always wanted a vintage South Bend 9" Junior, or something similar. Since I probably wouldn't use it as much as you pros, it's the one tool I've always wanted to "splurge" on, but just could never justify the cost).

[Cameron Gates]

Roweenie, how long are the 2 pieces of tubing and what is the diameter?

Dan's lathe idea seems like a winner, but I would think the pieces would have to be fairly long. My first thought was that, on a shorter work piece, the Chuck would suck up the heat and not allow the heat to be controlled at business end very well.

Dan, do you find that when using a BBb 3-jaw Chuck for this purpose that the actual jaw's contact point with the tube is small enough to not draw a good amount of the heat away?

[Dan Schultz]

.... Dan, do you find that when using a BBb 3-jaw Chuck for this purpose that the actual jaw's contact point with the tube is small enough to not draw a good amount of the heat away?

Give it an inch or so on either side of the joint.

BTW... all of my chucks are BBb. Do they make other keys?

[Doug Elliott]

Wouldn't a 3-jaw be in Eb?

[roweenie]

I seems to me it would be a pretty interesting lathe set-up to cut a half inch or so out of the middle of a tuning slide crook and braze it back together (in order to fit a slide to immovable geometry on a particular instrument without making a crook from scratch, etc.)

Bloke, you must be related to Karnak the Magnificent - this is exactly what I am (trying) to do, right down to the amount of material I'm removing.

[Donn]

All a "soldering jig" has to do is

- hold something still
- not become a serious heat-sink
- not catch on fire

If I were trying to butt two tubes, I'd think about a support that would hold them in place via gravity, a trough of some kind. Like a couple tubes wired up parallel. I'm assuming that the work doesn't tend to crawl around on its own, so gravity would be plenty.

If you had a lathe or some other way to do this somewhat precisely, would there be any point in trying to sort of mortise the joint, by tapering the edge? Taper in on one end, out on the other, so the joint sort of plugs together dry?

[roweenie]

Donn, believe it or not, the force of the flame coming from a torch is enough to move the item you are soldering, especially the heat involved in melting silver solder (@ 1125°F).

I'm sorry for asking what might seem obvious or simple questions, but my whole line of questioning is based on the fact that this kind of job requires extreme precision, coupled with permanent results. I want to "do it right" the first time!

[roweenie]

Excellent!

bloke "I told you there's always a reasonably easy way, and one that doesn't require a bunch of fancy $h!t."

THIS is why I come here to ask questions - what may appear to be "simple" to you pros, may actually be a major revelation to a challenged amateur like myself.

Thanks!

[Dan Schultz]

This type of thing is what makes repair work so interesting for me. Every job, no matter how simple on the surface, usually presents a unique oroblem.

Now that I understand what you are trying to do... I think I might just expand the ends a bit and insert a rolled piece of .010 thick patching brass inside to align the parts. Then apply the filler solder ... then sand the outside smooth.