Capillary gaps required for silver soldering.

Is it not like Loctite where roughing the surfaces with coarse emery paper provides myriad surface scratches a few thou deep for the liquid to flow through and form a grip?

I know that silver solder is a different alloy to sterling silver (92.5% pure silver) but the following anecdote might be of interest.

Some years ago I was given a small enamelling kiln which I thought might be useful for melting small amounts of sterling silver for casting small items.

To try it out I put a few grams of silver scrap into a dish type ceramic crucible and placed it in the kiln. The silver melted OK but it when cooled down I was surprised to discover that there was a thin film of silver underneath the crucible. It turned out that, unknown to me, there was a tiny, almost invisible, hair-line crack in the crucible.The molten silver had become sufficiently fluid to flow through the tiny gap.

Andrew

Have a look at a gap of 0.01mm., a gnats todger wouldn'tfit through it but the solder will When i got all my bit laser cut byMalcolm i drew them with that gap..no problem whatsoever, plus if too tight you can tweak it a bit but you cannot narrow it

I was scared of soldering, so i practiced on some scrap..No problems now

Hello Ron,

I don't have much problem silver soldering these days, as I have done a good number of boilers. Like most people replying, you state a gap measurement. Most manufacturers supply the gap range for the various grades of silver solder, so that isn't a problem.

The query I have, is how do you set the gap to 0.01mm ? Apart from the centre punch method, there have been no answers, I know the basics of the science behind the soldering. What I don't know is how do you jig the gaps?

Cheers,

Andrew.

I think there is a misreading somewhere, 0.01mm is less than half a thou' I think it should be 0.1 mm, 4 thou'

Duncan Mea Culpa yes 0.1mm

Job vacancy for a well-endowed Gnat

MichaelG.

My apologies to duplicating this thread.

I have asked the same question starting in June in the Workshop Techniques forum.

I also am confused, still.

I have never made any boilers, just about to start though.