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Solders for Enamel

  • December 21, 2015

    Please clear up for me what the difference is between eutectic and IT solders.  I bought eutectic solder for soldering under enamel, but have since been told to use IT solder.  I can find very little information about IT solder.  I trust this site to set me straight.

    Mary

  • Leader
    January 1, 2016

    You were right M.

     

    Euctectic Solder contains  71.9% Fine silver - 28.1% Copper  - Melting point is 1460 degrees -

    If you plan to place enamel over a solder seam, then EUTECTIC solder is used because it contains NO ZINC. You can fire colors directly over a eutectic seam or joint without enamel pitting. If using transparent colors over Eutectic solder on Sterling silver, it should be depletion gilded until the surface is bright silver before enameling.

     

    IT Solder contains 80% silver, 16% copper, 4% zinc - Melting point is 1490 degrees - Use Eutectic, IT or hard solder if the soldering operation will be done before the piece goes into the kiln or is torch fired - any enamel that touches IT or Hard solder will discolor because of the zinc content.

     

    Hard Solder contains 76% silver, 21% copper, 3% zinc - Melting point is 1425 degrees

     

    Before Enameling, if you solder a piece carefully that the enamel will not touch the seam, you can use Eutectic, IT, or hard solder.

     

    I have always used HARD solder to attach my findings on the back of my Saw n Solder Champleve before enameling the piece and have never had an issue with them falling off in the kiln -  When I first was starting out,  I was told to use IT for all findings because it melts at 1490 degrees, but later was taught by Kristin Anderson  and Linda Darty to use  Hard - I have never looked back. 

    In Linda Darty's book she states, " Use eutectic, IT or hard solder if the soldering operation will be done before the piece goes in the kiln or is torch fired. I find that hard solder holds up very well for the vessel forms I make and I like it better than IT because it is easier to work with. I also find it to be less brittle than eutectic solder and less likely to come apart if the piece gets too hot.  Keep in mind that the enamel will pit or discolor if it is applied over hard or IT solder because they both contain zinc. I always use eutectic solder that is made of only copper and silver, if I plan to enamel over the solder joint. If using transparent colors over eutectic solder on silver, it should be depletion gilded until the surface is brigh silver before enameling."

     

     

  • January 1, 2016
    Thanks for the comprehensive enameling solder education. It explains a lot of what previously seemed like conflicting information.
    M