Bullshit detector: claimed welding experience

silver solder is a recognised type of solder used in brazing.

The chap then told of high times and much money made when welding using solid silver rods. He said that when the rods were spent, he and co workers would pocket the stub ends for selling as silver scrap. Most of the prior conversation concerned arc welding, so I assume that is the flavour of work he was referring to.

Later, he elaborated on the extent of his welding skills by claiming that he could weld aluminium foil.

Both of the above strike me as bullshit, especially in the context of industrial applications, being the claimed field of expertise. I could perhaps imagine some fancy jewelers being able to do something along the lines of what was claimed.

So, was this all clearly bullshit, or could there be a grain of truth somewhere?

Cheers. Terry.

Silver soldering is done with gas. (Akin to brazing) Usually it's a silver alloy, not pure silver. Usually on copper with very fine joints. Done on copper pressure vessels where soft soldering is not strong enough. Only tiny amounts are needed in the fine joints. Nothing is wasted, the stub of one rod is usually welded on to the next rod (only takes a second) to prevent waste as the job progresses. Unless they were on the fiddle (but where would you sell such stuff?) Last thing I saw it on was mains pressure under sink electric water heaters. Not skilled work at all though, virtually anyone could learn in a few minutes.

I have only seen very thin aluminium welded by laser but is was an automated job, not by hand. I have been told it can be done by resistance welding. Doing it by hand would be some trick.

Jewellery can be repaired using pulsed arc welding and sterling silver filler. It gives a much better colour match to silver than the traditional silver soldering. However, I don't know a jeweller who would be likely to lose track of precious metal welding rod ends.

This video shows aluminium foil being TIG welded.

It would be a strange employer who didn't know the value of such scrap and allow it to be pinched.

Silver solder is commonly around 60 - 75% Silver and rarely ever higher. Items that subsequently require hallmarking need to be 65% or higher. The higher the silver content the better the colour match but joint gaps should be thin enough to be near invisible anyway.

A competent welder makes enough money such that buggering about flogging scrap rod is pointless.

That is possible with tig welding *if* you are very good

If he claims he was a welder a good check is to see if he has a daughter and no sons (a standard test that is quite accurate)

Notice that he used 2 metal blocks underneath the foil so that the heat would dissipate quicker from the actual welded joint

Damn! I'm a welder and I never knew it.

As others mentioned - silver solder is a genuine product, but it is not pure silver - far from it.. I have only ever seen it used as a brazing process ... there would be no stubs , as rod gets shorter would usually fuse it to next rod .... in any event don't think it would have high scrap value.

We used to friction weld aluminium conductors are, but not sure how you could do that with foil.

But ultrasound welding seems quite common:

I solder aluminium foil: All it takes is the right flux. Carrs grey. Evil stuff and do NOT use it without at least an open window, preferably in a fume cupboard.

doesn't need specail solder..60/40 works.

The silver solder that plumbers use for copper pipe is usually only 2% silver

Plumbers don't use silver solder for copper pipe.

Can't for the life of me think of any application where a plumber rather than say a boiler manufacturer would need to use silver solder and especially one with such low silver content

The low melting point solder I very occasionally use on some electronic circuit boards contains 2% silver (the remainder being 62% tin 36 % lead) There are also a number of high melting point soft solders containing the same amount of silver with the remainder being nearly all (90% +) lead and a very small quantity of tin.

On the other hand refrigeration engineers do commonly braze or hard solder* copper pipes, so they may sometimes use silver containing alloys.

Occasionally they do. I'm a retired plumber and on a few sites in London it was stipulated that silver solder must be used.

I expect someone else has already mentioned this (but I can't be arsed to read the entire thread). You can weld aluminium foil by friction. Two layers of foil are layed on top of one another. You then create the welded seam by spinning up a nylon disk to several thousand RPM and skim the foil surface with it. Now if someone could weld tin foil with an arc welder, that really would be a most remarkable feat!

You must have strange plumbing practices or a different set of words.

Look at the first one mentioned.

It is extremely common in Australia and I can not believe that it is not in UK by professionals. There is a whole range of fittings made specifically for the purpose. Home handymen have a different range of fittings with a band of soft solder in them, professionals do sometimes soft solder when they can't get their oxy near(or mapp gas in a pinch)

Quite common. It depends what's in the pipe.