Silver booty

[Rik ShawParticipant @rikshaw]

I was just going through yesterday’s car boot purchases when I found this age blackened coil in amongst an old box (3 quid) containing equally aged brass, copper and PB. Cross section is 5mm wide and 1mm thick and about three ounces total weight. I snipped of a small piece and a brief squirt of my cooks blow torch confirmed my hopes – its silver solder.

I obviously have no idea what the melting point is but it seems to melt as readily as my known stock of Silver-flo 55 but I can only do the rough comparison particularly as my Silver-flo is only 1mm diameter.

Without suitable equipment I am unable to more accurately check the melting point. Can anyone come up with a cunning plan?

Rik

[Rik ShawParticipant @rikshaw]

[not done it yetParticipant @notdoneityet]

Don't know how you might do it, but I would snip off a tiny piece and pop it in our kiln. Could even compare it with the other sample.

I remember someone who once picked up a new palladium/gold crucible, thinking it was platinum and subjected it to 'loss on ignition' temperature of over 1000 Celsius. That was an expensive mistake!

Take it to your local college is one option, if you don't have a kiln, and ask for help?

[mark smith 20Participant @marksmith20]

How do you know its solder and not just silver strip?

[pgk pgkParticipant @pgkpgk17461]

Hmmm.. a cunning plan? I know my daughter gets the jewelry she makes hallmarked… it can't cost much to get stuff assayed which would at least let you know % silver?? Then really all you need is a guide to whether this is low , med or high melt point if convinced it's likely solder from the assay result. Diameter of your other solder shouldn't have a bearing on comparisons so long as both are side by side on a good fluxed conductor such as copper??

[Rik ShawParticipant @rikshaw]

"How do you know its solder and not just silver strip?​"

​Mark – If the original owner/model engineer? had chosen to keep his silver solder in the same box as his non-ferrous stock it would make sense to me. Also, silver solder (55%) melts at a much lower temperature typically 630-660C than silver which melts at around 961.8C. —-Rik

 

Edited By Rik Shaw on 19/12/2016 17:04:19

[Michael GilliganParticipant @michaelgilligan61133]

Rik,

First … Congratulations !!

This is far from infallible, but the harder grades of silver solder strip are usually the wider ones: **LINK**

http://www.cooksongold.com/Solders/-Alloy=Silver_Solder/-Type=0/&prdsearch=y

MichaelG.

[mark smith 20Participant @marksmith20]

deleted

Edited By mark smith 20 on 19/12/2016 18:18:51

[mark smith 20Participant @marksmith20]

Hi Rik, i know this as i use Sterling and Britannia silver almost every day in my work. Although i use proper silver solder which melts between 667 centigrade and 800 centigrade. (usually between 55 -75% silver content)

How do you know who put the silver in the same box as brass etc… as it was bought at a boot sale

I was going to suggest putting a small piece next to a similar size piece of aluminium and seeing which melts first..

The higher silver content solder usually is stiffer than the lower melting point ones.

[Rik ShawParticipant @rikshaw]

You are confusing me Mark – "The higher silver content solder usually is stiffer than the lower melting point ones.​"

​Should that not read "The higher silver content solder usually is stiffer than the HIGHER melting point ones.​​" or what?——Rik

[mark smith 20Participant @marksmith20]

Hi Rik, im confusing myself but the solder i use tends to feel stiffer than the 55% stuff or lower that model engineers use for hard soldering. The extra easy stuff i use is lower silver content like 55% and is alot softer than the high melting point stuff. I think is the increase in zinc content that lowers the melting point alot. Whilst the copper content generally goes up with the higher temperature silver solders.

The so called medium silver solder i use is a bit of an oddity and has a higher silver content than all the rest.Melts at 720-765 degrees cent.

[Keith HaleParticipant @keithhale68713]

The stiffness of a piece of silver solder is no reflection on its'composition.

A rod directly extrudes to size is softer than one produced by spin-straightening a hard drawn wire!

1) Cut a small piece of your strip to a similar size to that you can make from your 1.0mm 55% cadmium free rod.

2) Place both pieces on a small sheet/strip of copper and apply flux paste.

3) Heat the two pieces eveny from underneath.

4) Observe when the two samples melt.

My bet is that the unknown material will melt just earlier than the known. It may even spread a little further!

My bet is that you have a 42%silver alloy with cadmium. 5 x 1 strip was commonly supplied to shipyards and the automotive industries. One way you could put down metal slowly. Turn it through 90 degrees and you had a thick rod and could put a lot down quickly

For the alloy to become so tarnished implies that it has been lying around a while. This may date it before anyone became concerned about the health risks for the model engineer of using such small amounts of silver solder.

All my other thoughts on original source etc stay with me!

Keith

[Rik ShawParticipant @rikshaw]

Thanks Keith – Just the sort of info I was looking for. I will follow your advice. I will experiment and post results here for anyone who is interested. Your "other thoughts on original source" are understandable given your business interests and I for one would not wish to press you for further detail — a nods as good as a wink ! ——–Rik

[John Stevenson 1Participant @johnstevenson1]

I found a bundle of silver solder in a metal skip years ago about 8 or 9" long pieces, 3mm diameter [ from memory ] and the bundle was about 1 1/2" round, used odd bit over the years repairing brass brush boxes on traction motors.

 

No idea what grade it is.

Edited By John Stevenson on 19/12/2016 23:12:05

[Rik ShawParticipant @rikshaw]

What flux did it work with John? —–Just curious.—–Rik

[John Stevenson 1Participant @johnstevenson1]

Tin of white flux that just said silver solder on it, Still got the tin, I'll look tomorrow.

Only have two tins of flux, pink for brazing, white for silver solder.

[Rik ShawParticipant @rikshaw]

Keith – CuP —– I followed your instructions but the Easi-flo 55 melted FIRST. Just to make sure I tried it a second time and still got the same result.

I have now unwound the coil of old solder in the pic and measured the length. If anyone is interested in guessing the length please have a go.

Nearest guess by this time tomorrow gets a brand new pack of ten top quality German made 3mm HSS drills in the post from me (UK bods only please) . Merry Christmas.

Rik

[ASFParticipant @asf]

Guessing 780 mm

[pgk pgkParticipant @pgkpgk17461]

1 cubit ,1 span, 2 handbreadths and a fingerwidth

Edited By pgk pgk on 20/12/2016 17:21:00

[Michael GilliganParticipant @michaelgilligan61133]

1800 mm

MichaelG.

[Colin HeseltineParticipant @colinheseltine48622]

2800mm

Colin

[Clive HartlandParticipant @clivehartland94829]

3100mm

Clive

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, 1176

Regards Nick.

[WatfordParticipant @watford]

try 2401

mike

[MetalmuncherParticipant @metalmuncher]

15 feet

[Author]

Posts