ASK METALSMITH SOCIETY - WHEN YOUR SOLDER IS BLACK AND WON’T FLOW

Posted by Corkie Bolton on

Recently a member of the Metalsmith Society community contacted me because they were having a soldering issue and were looking for some feedback. Their medium silver solder was not flowing and turning black. They had sent me this photo:

A little background information - they use a butane torch (which I personally have no experience with) they were using dandix flux, they soldered on top of a charcoal block, their solder joint was tight, their solder was clean and from a reputable company.

The following are some thoughts from various members of the community. Thank you to everyone that reached out! It's always hard to determine the best advice to give as there are so many factors, so these are just some considerations and suggestions:

  • Try using more flux.
  • Try focusing your heat on the ring and not directly on the solder.
  • It’s not getting hot enough, and they could also try reducing the amount of solder used.
  • Their butane torch might not be as hot as other butane torches.
  • They could try easy solder, since the butane torch doesn’t get as hot as other torches.
  • The butane torch doesn't  provide enough heat, when you put any heat on metal (solder and your ring in this case) it will star oxidizing, so the ring is getting hot enough to oxidize but by the time the ring gets to the right temperature for solder to flow too much oxidation is built up. They need a hotter torch, I use a hydroflux welder. Otherwise they need an acetylene or oxy-acetylene. Heating faster = less oxidation built up.
  • This happened to me because my solder wasn’t clean enough. They can pickle it and try again. Also butane gave me tons of problems because it doesn’t get hot enough. If they are using any kind of heat reflecting surface to solder like a brick it should help keep the piece hot. I ended up getting a map gas torch from Home Depot . I didn’t have the money to buy an acetylene or acetylene oxygen so I grabbed a map gas/propane at Home Depot. They are affordable. I got mine for about $60. The flame is big but it does the job and I haven’t melted any silver or fine silver. It melts the solder very quickly!
  • Their torch might need a refill. My flame gets weak when my fuel is low and sometimes the heat can’t get high enough to melt medium solder.

If you are struggling with a butane torch it is worth while to save up for another torch system, but I know that is not feasible for everyone. Hopefully this post helped with some ideas to improve the problem. Feel free to comment below if you'd like to add to the conversation!

Be sure to follow @metalsmithsociety and if you have a question feel free to DM me or use #askmetalsmithsociety
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3 comments


  • This post is so timely for me, I’ve had so much trouble lately with medium solder and my butain torch. I have an oxy/propain set up that I’ve been afraid of. This will light a fire under me to start using it (did you catch that?😄). Thank you so much for this blog.

    Jo ELLEN on

  • I use a butane torch and when my solder isn’t melting, the #1 reason is usually bc my torch needs a refill. After I fill it, the solder melts since the flame gets hot enough!

    Catpawgems on

  • There could be a few different reasons the solder is not flowing, but in this case, I agree with the others who said the torch is likely not getting hot enough. In particular, I think the last point about the torch needing a refill is most likely the case here as it happens to me with butane, too. This is one of the main reasons I am switching to acetylene. Try refilling the butane torch, pickling the ring to clean it, addding more flux and then firing it up again. Good luck!

    Lisa on

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