NB: journal entry for the Jewellery and Small object module at South bank Griffith university (QCA) to view the full journal click here
Week 3 : Annealing, soldering and texturing copper, brass and aluminium : jewellery and small object making
The following projects resulted in the creation of a ring (copper) using annealing and soldering , brass soldering experiement and three textures into aluminium plate
Annealing is a heat treatment that alters the physical and sometimes chemical properties of a material to increase its ductility and reduce its hardness, making it more workable. It involves heating a material to above its recrystallization temperature, maintaining a suitable temperature, and then cooling.
1. cutting of the brass and aluminium plate ( note that the ring made is copper at the end, this was due to a mixup in the acid bath, resulting in the brass ring being taken by another student by accident. Lesson learnt was to not leave your metals in the bath too long. The copper ring was one that was left over ) its important to only cut copper, brass and aluminium as steel will damage the blade.
Once cut to the desired lengths the next step is to anneal the metal, this will make it possible to bed the metal easily into shape. Bending metal hardens it . Hardened metal is brittle. Brittle metal snaps.
The idea is to heat the metal until it glows, in a well lit room it is very difficult to see if a metal is glowing. To make it easier to see, paint one side of the metal with flux.
When heat is applied to the flux (ie using a propane torch) it will become transparent once it has reached annealing temperature.
Above is a Fire brick, which will be used as a base when heating up the brass strips, a spark lighter ( gas lighters may explode ) and a propane torch. I found getting the right amount of gas to flame ratio difficult at first, it takes a little experimentation.
Essentially you are heating the metal strips up to annealing temperature ( flux goes clear ) then using tweasers, placing the hot metal strips into a ceramic container that is filled with water for cooling.
The next step is to place the metal strips into a citric acid bath. Why ? well when annealing metal, oxodisation occurs leaving some interesting paternisation. If you with to reduce/remove it, place it in the citric acid bath. Use the tweasers provided ( they are bigger and easier to handle ) also USE EYE PROTECTION
Soldering
Sorry for the lack of images for the soldering section.For the soldering I used silver solder, its stronger, safer and wont damage the metal unlike lead based solder. But it requires a much higher melting temperature than the lead based.
Step 1 : bend the strip of metal that has been Annealed into the desired shape, it does not need to be perfect, the shape will be refined after soldering.
Step 2 : cut pieces of solder into tiny sections, approximately 1mm in length
Step 3 : paint the join that you wish to solder with FLUX and place the solder segments onto the join, for a ring 2 small segments should be sufficient
Step 4: Light the propane torch, apply heat to the FLUX/solder until the solder looses form. Using a titanium tool spread the solder over the join and smooth as desired (this takes practice)
Step 5 : again place the metal into the ceramic container of water to cool then place in the acid bath.
NOTE: that the metal in this process is being annealed as well as soldered, so it is ready for reshaping once taken out of the acid bath
Step 6 : remove the ring from the acid bath, wash off with water and try with paper towel. The ring is now ready for reshaping
Step 7 : Reshaping, the tool used is similar to the tool used for measuring the size of a ring. Put the ring over the tool pushing it all the way to the bottom, by doing this the ring becomes rounded. Using a soft mallet gently tap the ring until it is rounded.
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| the above ring is the "replacement" ring after reshaping and some polishing. Bit disappointed as it looks like a bit of copper pipe but oh well. |
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| I also used the process of annealing and soldering on an irregular shape |
Adding texture to a metal surface
The metal used in these experiments was aluminium. Its a softer metal which makes it easier to work with and easier to get better detail. |
| Press roller for texturing metal surfaces |
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| These two samples were run through a press, which looks similar to a printing press |
Step 2: setting up the press, place the metal plate you with to emboss, the base plate ( in this case brass) and the material you wish to imprint into the metal into the press. Turn the cranks till they are firm and set the dials located on the top to 0. This is your start point.
Step 3 : now release the press and remove the materials from it
Step 4: re-tighten the press to 0 point, then go a further 1.5 marks to tighten the press fully. Why ? the added pressure will enable the metal to be imprinted
Step 5: run the metal,baseplate and materials through the press. Now your done.
Second technique for imprinting
The second technique is for larger less detailed patterns. The idea is to apply even pressure to the entire metal surface allowing for a higher relief of embossing.
Above , essentially a hydrolic car jack with two metal plates. Try to keep the presure between 1000 and 8000 psi
Step 1: setting up the design , The intention is to embose a piece of wire into the metal plate. Using the red card, register the piece of metal and the wire into the center of the plate. Place the red card into the center of the two acrylic panels.
Step 2 : Open the press to be just wide enough to fit the two acrylic panels ( which contain the card, wire and metal )
Step 3: Using the jack spanner apply presure to acrylic plates, I used approximately 3000psi of pressure.
Step 4: release the pressure of the jack using the release valve ( on this jack located at its bottom right hand side ) and remove the acrylic plates
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| This is the result of the impression of wire into the metal. |
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