Silver solder strength

I'm new to jewelry and I've been practicing my soldering by soldering flat copper wire strips (3mm x 0.76 mm, solid copper) to pennies. I've been using a small butane torch with silver solder. I do clean the surface of both the wire, the pennies and the solder with emery cloth.

My solders LOOK pretty good, and seem pretty tight...however I AM able to pull the wire away from the penny surface with my fingers - with some effort. Its not easy, but I don't have to use plyers. Once I've torn off the wire, the solder does look nice and evenly embedded in both the penny and the wire itself.

So, I guess the question is; how strong should my solder be? Is this a sign I'm not doing it right, or is this just the limits of silver solder under the circumstances.

Thanks!

P.S. It's only 2% silver in the solder. Maybe that's why its so weak?

If you can pull the strips (how long are they?) off the coins I'd be astonished if they are being properly soldered on.
Perhaps you could show us a close-up photo of a soldered joint and/or the two pieces once they've been pulled apart.

I think we need to be sure that you are using hallmarking quality solder and also whether hard, medium, or easy and what flux, or is it a paste solder? Dennis.

When done properly, no , you should not be able to break off by hand.
It may be that your torch isn't getting the items hot enough for the solder to flow properly.
Paste, in particular, can see to have melted but completely fail.

Hi, and thanks to all for the help. So, some pics and more information. (Sorry on the dropbox links. For some reason, Cooks is choking on the file size, even though they're all less than 300KB :"> )

This is 2% silver solder wire. I ordered some high silver content solder from cooks, but it is yet to arrive.
https://www.dropbox.com/s/6y2j3guenu...104411.web.jpg

The steps used:

1. First I cleaned the coin and wire with an electronics deoxidizer. Wiped clean with clean cloth. Used emery board to polish the solder points (both coin and wire…you can see the polished strip in pic 1). The wire, you may notice, is recycled (read: wrinkly). I don’t know if this matters.

https://www.dropbox.com/s/lh4v7svg4r4co7j/1.web.jpg

https://www.dropbox.com/s/ax3ofig1tzf05g2/2.web.jpg

2. I put flux on both the coin (center strip only) and the wire. Let dry

3. I heated the coin (only) until the flux bubbled. I touched solder to the coin, and it seemed to flow nicely. I then placed the wire onto the molten solder, and held both coin and wire under the torch for about 30 seconds (I learned this technique from an Andrew Berry video, as to not disintegrate or weaken the wire). The torch never left the coin.

It turned out to be a sloppy solder job, but it’s Monday :D I don’t know if it matters.

4. I let the coin/wire solder cool in air for about 60 seconds, and then quenched with room temp tap water.

5. Pics 3 and 4 show the solder right after, and again after being scrubbed with a wire brush, rinsed again, and polished with a cloth.

https://www.dropbox.com/s/c9g2zlrrkyazde7/3.web.jpg

https://www.dropbox.com/s/xj709baovjazg2b/4.web.jpg

6. Pic 5 shows both after peeling the wire off. The thing I notice is; both the coin and the wire seem to have a nice even layer of solder on them. It doesn’t look like I’m pulling the wire/coin from the solder…but I’m tearing the solder apart down the middle – leaving solder evenly on both parts.

https://www.dropbox.com/s/iqrk9nsiu2kf0l3/5.web.jpg

Do I just have cheap a**ed solder?

Thanks again!

OK. Well in a twist of irony, as soon as I made that last post, my good solder showed up and - problem solved. Beautiful, clean lines and I can't pull it apart anymore :D

Good to know. You CAN, in fact, pull apart cheap solder :D

Well as per my questionnaire above, I suspected that you used soft solder, which is also marketed as silver solder, but intended to be used with a soldering iron.

Jewellers would not give houseroom to that stuff, because it contaminates our work space with base metal filings and fragments, which can cause irremediable damage to precious metal work.

The confusion arises, because by tradition, jewellers call what they do 'soldering', when it should be called 'brazing'. The solder used in Jewellery making comes in four grades according to melting point. For most purposes we use Hard (750-780 degree melting point) and Easy (700-725 degree melting point). The medium quality does not flow as well, so many of us skip it. The generic name hallmarking quality solder is also used to denote its high silver content.

This solder re-melts at a higher temperature when reheating a piece, so contrary to general belief it is not necessary to change to an easier solder for sequential soldering, for at least two or three stages. Dennis.