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Hello all! Was wondering if anyone had any pearls of wisdom - I'm making a dress ring for a customer using 2mm thick flat gold wire which has been melted down from her old 9ct gold jewellery. However, every time I try to solder it (ensuring everything is properly positioned, clean etc) the join is brittle and just snaps. I'm wondering if the metal is simply too thick or whether it's the way the gold has been melted. Any suggestions? :-)
Hi Cat,
When you say it just snaps, do you mean when you are stretching it to size by hammering on a triblet?
When gold has been melted, it needs working to restore its properties, so has it been rolled in a mill to achieve that?
Next are you using pallions of solder, or paste? Paste solder will have a tendency to burn before it can flow properly, so causing a week joint.
Lastly, flat rings like you describe tend to open very slightly when heated for soldering, so it is best to prevent that with binding wire. It also helps to apply heat at the point farthest from the joint, at least to begin with.
Regards, Dennis.
Hi Dennis,
No, this is before I've started forming it into a ring. Basically, I'm trying to make a ring which curves down the finger at the front and back (see picture A) I formed the gold into a strip of 2mm thick, 7mm flat wire on a rolling mill. I then cut a v in the middle and bent it down and positioned it for soldering (see second picture) My intention with this was to begin to curve the wire to the right shape before forming it into a ring. However, each time I have soldered this section and gone to move onto the next step, the join has snapped. (see picture 3)
I have been using both hard and easy solder pallions with au flux, coating the whole piece in au flux before soldering. I have also let the piece cool naturally without quenching too quickly. The join has always been clean and fits together perfectly before I begin soldering (not evident from last picture as that was after a bad failed attempt!)
I appreciate your help with this!
Cat
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Sorry, I have very few further ideas about this, except that the metal appears to be unsuitable for re-use. Therefore:
Was it all hallmarked gold that you used? You can re-melt it and have it assayed at your assay office to be sure.
Depending on the result, you might add some higher carat to it, or sell it for scrap and buy new with the proceeds.
I notice that you are not using a charcoal block, which is more conventional for gold, but very much doubt that in this case you would do better.
Dennis.
This morning I thought that, if the assay is satisfactory, a caster might also be willing to cast your ring from your used gold, if you make it in wax first. Dennis
I have the same problem with gold d-wire (9ct) bought from cooksons. I have tried everything I can think of including working under extremely clean condition. I am trying to make a ring and have placed the ring flat on the charcoal block, both with the solder placed on the joint and pick-soldering. I have tried it with the ring held in tweezers and heating from the bottom - again with solder placed on the joint and pick-soldering. I have tried fast heating on the joint only all the way to slow heating of the whole ring. Every time I break the joint I can see that the solder flowed into the joint but it stays brittle and breaks when I try to round the ring on the mandrel. I have even tried soldering the joint with hard silver solder and that worked perfectly. The solder I am using is 9ct hard bought from cooksons. I have been at this for at least 12 hours now and I am reaching the point of despair. I solder both 925 and 999 silver without any problems - what trick am I missing with soldering gold?
If the joint is close fitting, so that you can see no daylight through it and the solder flows easily when the gold glows red, then it should be strong.
Check the flow of a small piece on a scrap of silver to see what happens. Use borax or Auroflux for this. Could it be that you ordered solder wire and were sent gold wire instead?
Phone Cookson for a replacement and if you want to get on, request medium solder instead. Dennis.
Afterthought.
A second possibility is that the joint is opening when you heat the ring. Use binding wire to keep it together and heat at a point remote from the joint until soldering temperature is reached. Dennis
Thanks Dennis. I do use binding wire but after your message I tried to ensure that the joint stays closed by using clamping tweezers and heating from the opposite side but the wire fractured into four pieces. Guess it has been heated too many times. Will I have the same sort of problems with 18ct? I only used 9ct as part of my self training.
No, gold is really easier than silver and 18ct is easiest of all to solder. You have done all the right things by your description, so we must blame the solder (you haven't mentioned flux). As I said above, I would test a bit of your naughty solder on a scrap of waste and see whether it will flow. If not it is not solder. Dennis.