Thursday, February 7, 2013

Soldering Tips 2

This is the second of my series of posts on the wonderful world of soldering. If you missed the first one you can find it here, but before you read any further, a health warning - learning how to solder can lead to creating even more wonderful jewellery and is highly addictive! However, turning on the torch for the first time and then turning it on a piece of silver that you've spent ages preparing can be pretty daunting. Hopefully these tips will help make you feel more confident.

Bangles are one of my favourite pieces of jewellery to make - and my solder joins are hard to find by the time I've finished!

The theory!
When silver is heated to near melting temperature its crystals move apart, opening up microscopic spaces. Soldering uses an alloy that melts before the silver does and then flows into the spaces in the silver, so that the solder actually becomes part of the piece of work. This is why you can file and sand the excess solder from the surface of your work and (hopefully!) leave a piece with an invisible join.

What you need for soldering to work.
First of all, you need a clean piece of work (dirt will stop the solder from flowing) with a good fitting join. If there is more than a very thin hair-line gap between the two pieces of metal then the solder will flow into the two pieces and not hold the join together.

Secondly, you need flux, a chemical that makes the solder flow when it's melted. If you don't add flux to your work then the solder will just ball up rather than flow into the join.

Thirdly, you need the right sized flame. Solder is melted by the heat of the piece of silver, not by the heat of the flame. If you don't use a torch with a big enough flame then the piece of silver won't heat up to the temperature needed, but then again if you use a torch with a flame that is too big on a relatively small piece of silver then you risk melting your work! I've got two hand torches that I use in classes - a small butane torch that I use for small pieces of work, and a larger butane/propane mix torch that I bought in from my local DIY store that I use for larger pieces of work. I've also got a more professional torch that runs on propane gas bottles, but the other two will do for now! You can see the torches in the photos in my first soldering post.

And of course you need some solder! Use just enough to fill the join. It's quicker to cut a new smaller piece of solder than to file off the excess solder afterwards!

When you heat the silver the flux will first of all bubble up - the piece of solder may "jump" off as the flux dries. If it does (and it does it to everyone at some point!) just turn your torch off and move it back again!

The flux has dried and bubbled. The solder is inside the ring and the heat will draw it through the join.
As the silver gets hotter and closer to soldering temperature the flux will start to take on a glassy appearance and the silver will glow a cherry red - if the glow becomes a brighter, orangey red then take the flame away immediately as you are getting too close to melting!

Nearly at soldering temperature - the flux has taken on a glassy appearance
 If your solder doesn't melt and flow then take a deep breath, remember that it happens at times to every silversmith, no matter what their experience, and try again! You will need to quench your work, clean it in safety pickle and apply more solder and flux as needed.

The flame was on the outside of the ring. As the solder flows towards the hottest part it flowed through the join to the front. If I can see a line of solder on the front of the work I know that the join is strong.
Oxidisation forms on sterling silver when you heat it and this needs cleaning off in safety pickle (see the first soldering post) - it will then take on a white-ish appearance.

It is surprising how long you can keep the flame on your silver without getting close to melting it, but the trick is to keep the flame moving and to watch out for the colour changes - as I said, an orangy-red colour shows that you are getting close to melting temperature. I often get my beginners to deliberately melt some scrap silver before they start soldering so that they can see the colour changes that the silver goes through as it gets hotter, and if you do this and want an idea of what to use the melted scrap for, have a look at the earrings tutorial I wrote before Christmas.

A couple of trouble-shooting tips for you:
  • If the solder has jumped to one side of the join rather than through and across the join then you have probably heated up that side more than the other as the solder will flow towards the hottest part of the metal. With more experience you will be able to move the flame to help draw the solder to where you want it to go.
  • If the solder has balled up rather than flowed across the join then you have either directed the flame to much onto the solder itself rather than onto the silver or have not used enough flux.
Probably the most important tip I can give you is to take your time. I find that a lot of beginners I teach think that they have to be very quick with the flame. Afterall, they've just spent ages sawing, filing and sanding, and it's natural to be worried about melting that first piece of work, and to assume that the best way to reduce the chance of melting it is to be as quick as you can. However, if you slow down, keep the flame moving and watch for the colour changes you will actually have far less chance of melting your work and the solder is far more likely to do what you want it to do.

Good luck - and have fun! Soldering opens up a whole new world of jewellery making! My next soldering post in a couple of weeks time will include a tutorial to encourage you to use your soldering skills.


  1. Thank you, I'm just learning and this post will help me so much

  2. Thank you so much for sharing your experience with us. I've not much experience in soldering jewelry components - although I've made many a stained glass window. I can't wait to try this.

  3. Another great post and look forward to your next one! Thanks so much for sharing your wisdom!!

  4. Thanks so much! I'll go back and read Part One too! I'm itching to try soldering!

  5. Thanks Jo, I'm really interested in soldering but I think I have a few skills to learn before I jump on this!

    For those of you in the know, how big do you have to go before you need to move up to a plumbers torch? I have my eye on a max-flame hand torch that will apparently give me a bigger flame than a standard torch, any idea what the limits of that wuld be?

    Looking forward to your next post :)

  6. Thanks for this post, Jo. I once melted a ring that I'd spent hours on, so I appreciate your advance to take your time and pay attention to the color of the silver.


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