Monday, November 3, 2014

In The Studio - Making Rivet Heads

See how close the rivet heads
are to the U shaped elements?
The other day a friend of mine asked for help getting ready for a show after she injured her hand. One of the tasks I agreed to do was to rivet a brooch that had been partially completed. Kim had already cut the backing, soldered pin parts, drilled holes for the rivets, and attached squared off, U-shaped elements to hold a chain. The rivet holes were really close to the U elements, and since I don't do much riveting on a regular basis I was worried that I would mar the metal or the U elements while hammering the rivet head. I was originally taught to rivet both heads on the wire while it was in the rivet hole - moving back and forth from one side to the other, but I knew I needed to alter that technique to complete this project.

I curled the ends of the wires, so they
wouldn't fall out. 

First, I tried to rig a micro bench block. The rivet making theory is that metal has to touch metal has to touch metal - hammer to wire to steel bench block. But with all the bits that were soldered to the back, I couldn't easily place the wire on my 4" block to rivet it. So, I took a small dapping tool, turned it upside down, fitted it into my vise, carefully settled the wire onto the flat end of the mandrel, and started tapping away. It worked, but the wire kept slipping around and I formed a very unattractive rivet head.

You could also perform this technique
using a wire gauge. Instead, I just took
a scrap piece of brass and drilled holes
with the drill bit/wire gauges I use most often.
Then I thought if one rivet head was already formed, I could easily thread it through from the back and just complete the connection on the front of the pin. I used my butane torch to form a ball on the end of a piece of 18g wire (the size of the existing holes), drilled an 18g hole in a piece of brass and all the way through my bench pin, threaded the balled wire through the brass and bench pin, and hammered the ball into a rivet head! So easy. I'm going to use this method from now on. I'm sure other fabricators have already discovered these tricks, but they were real "aha!" moments for me.

Some folks have trouble balling the end of sterling wire without getting an unattractive rippled surface. This ripple is just like reticulation, it's the copper content of the sterling moving under the top layer of silver, deforming it. Don't quote me (perhaps our Tech Advisor and resident goldsmith, Janet Alexander, will chime in in the comments section), but I think this effect has to do with the rapid cooling of the metal.

Oxidation formed by balling wire
is really thin and can be removed easily
with sandpaper. No need to pickle.
What I do is to hold the wire perpendicularly at the very tip of the inner blue flame (which is the hottest part of the flame) until a ball is formed, but instead of quickly removing the wire, I linger a second or two slightly above in the bushier part of the flame and very slowly move the wire upwards to cool it. Then I drop it in water to quench it. This slower ball forming method has never failed me. I always get a smooth sterling ball. Of course you could use fine silver, which doesn't deform at all, but fine silver is softer than sterling and isn't always an option.

I'm so glad I was able to help out a friend, and learn something new in the process.

Posted by Lora Hart ~
Artistic Advisor

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