dragonfly railing drawingSculptural Art Railings :
Silver Soldering Metals

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silver solder - catails

cattails forged from solid copper and steel

"One of the design elements I like to include into many projects I work on is the addition of color through the use of copper or brass. But the biggest problem which can arise is in the joining of dissimilar metals."

I don't like to paint the work I do because paint takes away from the natural colors and textures which can be achieved with patinas on both ferrous and non ferrous metals. Copper and brass both have the ability to generate natural colors from the formation of oxides on the surface of the material, but the biggest problem arises from joining dissimilar metals.

I use to think that it was impossible to join copper and steel until I ran across silver solder. This low temperature alloy of silver, copper, and zinc has the ability to join dissimilar metals and still give strong joints.

The trick to achieving a good strong joint is in preparation of the joints to be soldered. The pieces to be joined must be clean of all grease, oxides, and should have a smooth surface to allow capillary action for the flow of solder throughout the inside of the joint.

silver solder - applying flux

applying flux to surfaces to be joined

silver solder - flux dried surface

flux only surfaces to be soldered

After cleaning the pieces and checking for proper fit, the areas to be joined are coated with a flux which prevents oxidation of the joint. Flux also helps keep the metals clean during heating with an active acid in the paste.

The silver solder I use is a hard wire solder which comes as a roll. The flux is separate from the solder and is usually thinned with a little water to help achieve smooth application. I use a separate container that I add water to and then apply it only to the surfaces to be joined. After applying the flux, I allow the flux to dry before setting the pieces together.

One of the things you should be aware of when soldering joints is that of distortion and movement while soldering. If your joint is complex or angled, wiring of the pieces may be necessary to prevent them from moving.

Since these cattail joints are simple and the material is heavy, the only concern I had was with the sliding of the joints due to gravitational pull. I made sure that the pieces were plumb and level in all directions and simply allowed the weight of the pieces to keep them from moving.

You see, as the temperature rises from the heating operation, the flux liquefies and becomes real slick. If the pieces are not set properly, they will simply slide off the joint.

silver solder - soldering catails

oxyacetylene silver soldering of joints

silver solder - completed catail

finished solder joints prior to cleaning

The silver solder I use has a melting temperature just under 1000° Fahrenheit and requires the use of a #10 rosebud due to the thickness of the copper and steel being joined. Uniform heating is required for the solder to be pulled into the center of the joint.

I slowly heat the joint all around and use a slightly reducing (more acetylene) flame until the copper and steel start to get a dull cherry red color. Then I touch a straightened section of silver solder to the edge of the joint and barely touch the solder with the tip of the flame.

What happens next is that the solder begins melting and is pulled into the center due to the increased heat in the middle. After depositing the solder, I go back over the joint with the torch and watch for the solder to spread over the outside edges of the joint.

Once both solder joints are completed, I pause and allow the piece to cool just enough to loose it's red color, then quench it in my slack tub. This action helps blow the scale and flux off the piece. The cattail is then left in the water to soak for several hours to help remove the crystallized flux.

Design

Processes

Installed


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E. Vega Studios

p h o n e : 9 1 9 - 3 6 7 - 7 2 3 3

apex, north carolina

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