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I want to make some glass jewellery with copper foil, but obviously can't use my usual lead solder that i use for my stained glass art, which is the best lead-free solder and what flux would it need. Will my soldering iron work? its just a normal hobby one that i use for lead solder.

Thanks Emma

Emma
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  • Site quote "Questions seeking recommendations for specific products or places to purchase them are off-topic as they are rarely useful to others and quickly obsolete. Instead, describe your situation and the specific problem you're trying to solve." – Harry Svensson Jul 14 '17 at 04:33
  • Why won't your ordinary solder work with copper? I have soldered so much copper with ordinary leaded solder and also with lead-free which needs a higher temperature. Is it for aesthetic reasons? – Solar Mike Jul 14 '17 at 04:38
  • @SolarMike: Ordinary lead solder will of course work just fine on copper foil. It has two down sides, though. Lead solder isn't very strong mechanically, so isn't good for anything that may be pushed or pulled - jewelry made that way would tend to fall apart. Second is that it IS lead. Do you really want to wear something with lead in it? – JRE Jul 14 '17 at 05:29
  • You will probably want to use silver solder. I don't think you can use a regular soldering iron with it. It won't get hot enough for one thing, and you'd have to at least change tips since you don't want to get lead in with the silver. Best thing is to ask at a hobby supply store, or someplace else where people make jewelry. EEs can tell you a lot about solder and flux, but very little about making jewelry. – JRE Jul 14 '17 at 05:33
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    I'm voting to close this question as off-topic because it has nothing to do with electrical engineering. – JRE Jul 14 '17 at 05:35
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    @JRE if the joints are not in contact with your skin then the lead content is academic... Lead-free solder is also a possibility which i did mention - needs a higher temperature and strength issues may be reduced by the design. Silver solder is closer to brazing processes in terms of temperature and will definitely need a better / hotter iron. Also, engineers use silver solder for many things (tool making etc) and I, personally think, Emma made an intelligent assumption that some useful info could be found here. – Solar Mike Jul 14 '17 at 05:46
  • @SolarMike I partially agree with you. Although the problem of the OP is not directly related to EE, the technical problems involved do have relevance for EE (e.g. soldering a copper foil for EM shielding; soldering silver-plated copper (or other alloys) in waveguides manufacturing/assembling, etc. ... – LorenzoDonati4Ukraine-OnStrike Jul 14 '17 at 07:48
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    @SolarMike ... I said partially, because: 1) the question as it stands could have been formulated in a way that better fitted this site (the title is quite off-topic), without impeding the solution of the OP's problem; 2) probably (but here I'm not sure) EE.SE is not the best site of the network to find a solution, maybe Engineering.SE could be a better place to search for an answer. – LorenzoDonati4Ukraine-OnStrike Jul 14 '17 at 07:48
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    @LorenzoDonati I think as soon as jewellery appeared in the title or body it raised warning flags... but sometimes it is worth remembering that processes can be used in many walks of life! – Solar Mike Jul 14 '17 at 07:52

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You can try flux-core lead-free solder. It's typically mostly tin with a bit of copper and sometimes other metals. It's not as shiny as electronic grade eutectic solder (dull grey). The flux is in the core and is sufficient for soldering clean bright copper surfaces together.

I have no information on the biocompatibility of (for example) Sn99.3Cu0.7 solder for long-term contact. You should clean the flux off after soldering with an appropriate solvent such as IPA or lacquer thinner).

Melting point is higher than normal Sn60Pb40 or Sn63Pb37 solders- by perhaps 50°C so set your soldering iron to a higher temperature if it is adjustable.

Jewellery making suppliers may have other options for you such as colored solders that match metal colors, but I think they are mostly silver solders that will require a small brazing torch rather than a soldering iron. Some silver solders may still contain cadmium so take care if you start looking at unconventional sources. NSF approval is a good indicator it's probably not overtly toxic.

Spehro Pefhany
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