Torch-enamelling of a 925 silver bracelet with multiple solder points

25 september 2014 // Door webmaster //
28-01-2005
Shubhra Singh
Could you please advise me regarding torch-enamelling of a 925 silver bracelet with multiple solder points which I’m afraid will break apart and constituting wires which I’m afraid may get deformed/burnt?
The item to be enamelled is a rhombus shaped cast sterling silver piece 2cm on each side and 1.5mm thick which is soldered on top of an open bracelet formed by three 2 mm diameter wires which are wider apart at the center and soldered together at the two ends. (The bracelet looks like a wrist watch.) Only the central rhombus piece is to be enamelled.
I use a butane torch for enamelling and use both transparent and opaque enamels. I do not counter enamel my pieces.
Thanks and regards,
Shubhra
29-01-2005
Philip Quanjer
I think I get the general picture, and I shall ask advice from some silvermiths/enamellist. However, could please clairfy the following. Have you already soldered the 3-wire bracelet, and if so, with a hard solder? Did you have in mind to enamel the rhombus and then solder it to the bracelet, or were you planning to do all the soldering first and the enamelling subsequently?
Please clarify these points, and I will forward your question.
29-01-2005
Shubhra Singh
Yes, the piece has been soldered using hard solder. I’ve never tried soldering an already enamelled piece…so far I’ve been enamelling small silver pendants using a paste of brick dust (that’s what they call it in India, I don’t know the technical term, sorry!) to protect the soldered loops and bails. This is the first big item I’m trying to enamel so I’m jittery. If enamelling doesn’t seem possible I’ll get the recess oxidized.
29-01-2005
Allan Heywood
The same technique should work for the larger piece – provide as much protection for the wires and anything that isn’t to be enamelled from the direct flame as possible by using the wet brickdust and little bits of cut up tin can as shields, so that only the underside of the rhomus receives direct flame – start with a cooler bushy flame and if that doesn’t give enough heat gradually increase the amount of air until the bit is hot enough.
Don’t have the tin can bits in contact with the silver though – if the metals get hot enough the tin might alloy with the silver (unlikely but possible).
Allan
29-01-2005
Irene Schildkamp
Difficult problem; due to the clay you must add more heat, without it the piece will fall apart. I only do such jobs in the kiln. Would make a thin layer of clay upon which the bracelet rested. However, in a kiln one can control the temperature. I think it is difficult with the torch….
Irene
29-01-2005
Walther Carpaij
As regards enamelling soldered object: I have done that before, but never with a torch. If the seams have been soldered with 800 °C (1472 °F) solder, the job can be done. Covering the soldered points with clay or plaster, cool paste, is not so effective. At any rate one must be very careful not to contaminate the enamel, as this will affect the colour.
Why not use a kiln, when you can control the temperature? Because silver is such a good heat conductor, using a torch to fire the enamel will apply the same heat to the joints.
Walther
29-01-2005
Phil Barnes
I think the answer to this is where to begin ???
I can envisage the bracelet, and I can see the concern in raising the temperature close to the hard solder running point, during enamelling. when firing with a torch the problem is one of iregular heat, also a firceness of flame.
Suggestions….before enamelling the actual piece, try out the way in which you will fire, i.e what sort of trivet or mesh would be better, how can I give as much support to the piece as possible, in what direction will the flame be applied, always bring the flame on from behind the enamel, never directly onto the surface, rig up the stand on which you are going to fire the piece, and try and imagine what will heat first, what will be most likely to be effected etc. by placing small pieces of firebrick over the delicate wire work for instance, would absorb some of the heat and help even up the firing, solder joints can be protected. Rouge powder mixed with water and painted on is probably what he means when he says brick dust. There are such things as cool heat, that will protect stones even when soldering right next to them, but personally, I would suggest looking carfully at the way in which you are going to fire….. that is probably going to be the difference between success and failure, under fire slightly on the first coat, increasing intensity as you go. He says he uses butane…. but what sort of torch? compressor? mouth blown, foot bellows.. who knows in India what is available.
Start with a soft flame, gently increasing the heat, and keep moving the flame in a circular motion to heat on an even level…… take it easy, slowly, and be brave !! keep your eyes not only on your enamel, but also keep a close eye on all your solder joints…. even when you take away the flame.. the piece is still building heat, so keep this in mind, and look to take the flame away sooner than later.
I take it that the piece was made by the same person…… so he has gone through several solderings, the enamel will always fire before the solder, so as long as he is carefull and doesn’t OVERFIRE then all should be well…. Best of luck,
Regards,
Phil
29-01-2005
Karen L. Cohen
I might try this in a kiln at low temperatures (1350-1400 °F), but I’d be wary about using a torch. But to try it, my inclination is to detach the rhombus from the bracelet – enamel it – and then solder it to the bracelet using a low temp solder. To enamel, though, I’d first depletion guild it so that fire scale doesn’t interfere. Linda Darty teaching champlevé on sterling where she solders a pierced piece of metal to a back plate with hard solder, depletion guilds it, enamels it, then solders the finding on the back. So this could be doable, too.
I’m curious what others have to say.
29-01-2005
Lilyan Bachrach
re enamelling on sterling: My book, Enameling with Professionals, should be helpful for torch firing. Two of the texts explain how those enamelists enamel with a torch.
Basically to enamel on sterling – you need to bring the fine silver to the surface. I’m not certain if that is too high for keeping hard solder intact. I usually use IT solder and enamel either on fine silver or copper. For jewelry piece that is to be set or attached, I use the thin 28 ga.
Lilyan Bachrach
29-01-2005
Edmund Massow
How shall one help here? Every advice can be wrong.
Soldering correctly with hard- or enamel-solder, an ocher or other soldering-protection isn’t required. Perhaps the anxious lady should make some samples at first before she works on a labor-intensive workpiece. Or she should make a silversmiths/enamel course too !! But if the lady is courageous, she shall make the workpiece like she has made it till now: fire carefully, or find an expert in his workshop. One really cannot advise her increase.
Friendly regards,
Edmund
29-01-2005
Irakli Megrelishvili
Hello dear friend!
I have closely read your letter and I think that I can help you. Very much frequently we jewelers – enamellers collide (face) with a problem as to save from high temperature of a place soldering. The main condition in such punctilious a question it, calculate all technical operations up to that while we shall start performance our work.

  1. In the first if you be going to enamel an openwork complex (difficult) thing. Mine to you advice (council); use only pure (clean) silver of 99.9 % of test.
  2. In the second, you should solder a product high-temperature solder.
  3. In third, (after end jeweler operations) use the furnace, (for roasting enamels).

Composition of high fusible solder for silver (in a percentage parity (ratio).

  • Pure (clean) silver 80%
  • Copper 8%
  • Zinc 8%
  • Tin 3.5%
  • Aluminium 0.5%

It will be very interesting to me to receive the answer from you, after that when you perform your work!
Yours faithfully jeweler – enameller
Irakli Sergio’s Megrelishvili

29-01-2005
Christine van der Ree
Dear Shrubhra,
I think it is possible to enamel your piece but it depends very much on the construction you made for the bracelet. Does the centrepiece rest on the wires or are the wires soldered onto the rhombus shaped piece? And if so, did you for example drill holes and soldered the wires into those holes? The stronger the construction the less fear you need to have while enamelling your piece.
It is also very important that you make a good trivet for example out of steel wire mesh, to support the whole thing. It should be steady and you have to be able to get your torch underneath. Although you will heat the centrepiece the most, the whole object will heat up because of the good conducting properties of silver. Beware that wires will expand as well because of the heat. So don’t tie them up, this will only cause stress. Since you have been torch-enamelling before you probably know how to do it. Keep the flame under the piece (don’t let the flames touch your enamel).
Good luck with it!
Kind regards,
Christine van der Ree
29-01-2005
Victoria van den Bergh
Very interesting! But also difficult to visualise only from the description. The part that needs enamelling has been cast, I guess, and is hence solid. If so, it needs a lot of heat before the enamel starts flowing whereas the bracelet is vulnerable to the flame. My recommendation: suppport the frame very well with netting or other trivet(s), you must really ‘build’ some support and then cover it with ‘brick clay’. Give it time to dry and then check whether it is supported efficiently, add some more wet clay if need be. You subsequently have the advantage of a torch: you can aim right at the center of the part to be enamelled. Please give a report of how you fared!
Another recommendation: I would enamel the central part separately!!!! And subsequently apply a technique of joining, such as the use of screws or nailing.
29-01-2005
Nancy Levine
I would think using a kiln in this case might be better than the torch since the temperature can be more controlled. If this is not possible (which is implied), then the worker needs to build a rough copy of the piece and solder it together with hard solder. A first coating of enamels should then be applied to see how the hard solder, which should allow leeway for the piece to be fired and the solder to remain intact, reacts. If all goes well with this, there are additional considerations to be addressed. Sterling silver should be covered with enamels which have a melting point less than that of hard solder (1450 °F) and which also have a coefficient of thermal expansion that fall within the limits of 280-450 as indicated in Thompson Enamel’s catalogue #867, otherwise there is danger of cracking as the expansions will not overlap sufficiently. This same catalogue lists the expansion ratios for all enamels in the Thompson line at that point as well as fusion flow at 1450 °F, and dilatometric softening point. It is a wonderful treasure for those of us who have old enamels left. A full discussion of thermal expansions can be found in Glass on Metal, Vol.2, #3. Additionally, the fewer the firings the better as the silver will tend to darken with each firing to the point where it is unsightly and the solder points may weaken further.
Good luck!
Nancy Levine
29-01-2005
Diane Merrill
Don’t do your project this way. You can expect much contamination & uncontrolled effects and an unrefined product which will not be durable. Bracelets get the most wear and tear of any item of jewelry — if anything they should be REALLY well made so they can survive this use. Counter enamel enables the enamel to resist flaking off. Not using it reduces the reliability of your workmanship lasting. Hard solder (melting point of 1400°F) will release at the temperatures of medium fusing glass (1450°F). Not a well proposed method here. Try another tactic. Yellow ochre will retard the melting of a solder joint …. but it reacts with enamels and makes for a dirty color and contamination.
29-01-2005
Shubhra Singh
Well, I’ve done some experimenting …. I made a cruder form of the bracelet using a 2 mm diameter wire bent to a U-shape at two points (forming the ends of the bracelet) with the ends of the wire meeting at the center where I soldered a similar 2 mm thick rhombus shaped piece. I placed it on one corner of a flat wire mesh with the central portion resting on the mesh and the ends dangling freely. I first tried torch enamelling it after protecting the soldered portion with a paste of brick dust, but the enamel took an eternity to fuse, though eventually it did. I removed some part of the enamel and tried re-enamelling the piece with the soldered part exposed to the flame – it took a relatively shorter time and the wire and the soldered portion still remained unscathed.

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