Help soldering 18ct white gold!

[Jensi]

Hello,
I am new to the forum and I'm looking for some help!
The problem I'm having is soldering 18ct white gold flat surface to flat. I bought it in strip form to make rings using two layers of sheet soldered flat together and then turning that into a ring. I bought the medium 588 solder to go with it. I use my borax cone and dish for flux and my torch is a Go System from B&Q.
I was never taught how to use gold but have previously made 18ct yellow gold rings which has worked quite well!!
I was wondering if i'm doing something wrong with the 18ct white gold, or if it's just difficult to work with?
Thanks
Jen

[Dennis]

Hi Jen,
As I understand it you are sweat soldering one piece of sheet on top of another but what exactly is happening? It should work perfectly well.

Anyhow, here is a check list:

1. Make sure the surfaces to be joined and also the solder are cleaned with an abrasive pad.

2. I am assuming that the top layer will be narrower than the bottom layer. Slightly bevel the lower edge of the top piece to hold back the solder from escaping later. Turn it over, warm it slightly and flux well. Personally I would prefer Auflux.

3. Thin the solder, distribute fluxed pallions evenly on the fluxed surface about 4.0 mm apart and melt them until they just run. Leave to cool a little to avoid the metal buckling, and if quenching, just use water and then dry the surface.

4. Again slightly warm and flux the surfaces to be joined. This pre-warming makes for a more even coat of flux. Now put the surfaces to be joined together and heat until you see the solder glinting at the edges. Always move your torch aroud a lot to avoid over-heating one area. Allow to cool a little again before quenching in water.

5. By not pickling until you have inspected the work, you have a chance to reflux and reheat it without contamination.

6.It is also helpful when sweat soldering to stop the top sheet sliding around as the solder runs. For this I use two or three cotter pins as clips, adjusted to exert very light pressure. If new they need to be well heated to burn off their zinc plating. For gold it is usual to use a charcoal block, but not essential.

Regards, Dennis.

[Jensi]

Hi Dennis,

Thank you for your quick reply and check list!
I knew there would be some vital piece of information I missed out, the problem I am having is the solder is not running. The solder is melting in the usual fashion but it staying very close to it's original point of contact. This has left me with a length of sheet with solder joins every 5mms along and big gaps elsewhere so I am having to add more solder into these points by trying to place it in between the two bits of sheet!
I have done my best to keep the heat even over the whole length and have actually bent the rings round to their ring shape to help keep all the metal under the flame so it's always the same temperature.
That's clever about the cotter pins, great tip! I also wasn't aware charcoal would be used. I have both charcoal and honeycomb style block.
Thank you for the tips. I was wondering if my flux was the problem, or perhaps I have now heated the metal too much and ruined it?!
It's all a lovely learning curve really!

Thanks for your help.
Jen

[Dennis]

Yes sadly an expensive learning curve with gold, but if you are doing more I would suggest you get a small bottle of Auflux/Auroflux. I also use it for silver actually, as it bubbles much less.
Once soldered inadequately it is difficult to add more solder neatly, but the big deterrent will be residues of pickle. these are best removed by boiling in a solution of soda crystals (from the supermarket) and then clean water before you start again.
I sympathise, because I did a lot of that when I started. regards, Dennis.

[Jensi]

Hi Dennis,
I will try some of your tips at the workshop this evening. Here's hoping some of them work and I make some progress!
Thank you very much!
Jen

[Jensi]

I tried the soda crystals in boiling water followed by a washing out brush with washing up liquid and some clean water. Got out my old charcoal block, changed my canister on my butane/propane torch and tried a gentle flame for longer. Now the white gold bands are properly soldered though I'm still getting little gaps and pockets where the solder seems to be creating dips in the join.
However your tips were great.
Thank you again!
Jen

[Dennis]

Yes it is really difficult to add more solder at this point, but maybe you will use more pallions from the start, the next job you do. Pallion shaped dips, called ghosting, sometimes occur when a piece of solder is heated directly with the flame and sinks in to the surface.

Well done to have improved on it, kind regards, Dennis.