clairemaloney

Once shaped ready for enamelling, copper must be cleaned with soapy water and a scouring pad to remove all traces of grease, including that from fingerprints. Once washed and dried, hold only by the edges – do not touch with your fingers or the wallpaper paste won’t stick and the enameling will fail.

1. Clean copper with soapy water & scouring pad, dry and hold by edges only.
2. Cover copper area to be enameled with wallpaper paste
3. Sprinkle over enameling powder (powdered glass, same as ceramics glazes.) Make sure you have an even and thick covering, using a sprinkler and holder, tapping gently allows more control over where the powder falls and gives a more even covering. Start with the edges and work inwards, making sure no metal is left showing.
4. Leave to dry on top of kiln on a trivet for a minute or 2 (wear gloves as top of kiln is burny burny hot hot!)
5. When kiln is at 800 degrees, using tongs and wearing gloves, place copper on trivet in kiln.
6. Leave it in the kiln until the temperature gets back up to 800 degrees.
7. Check enamel is smooth and melted – if still bumpy leave it a bit longer. Once it’s ready remove it with tongs & place on metal strip between the kilns.
8. Leave it for a minute to cool slowly – if you plunge it straight into the water the enamel will be shocked, seize and crack or come straight off.
9. Plunge into water to quench after a minute or leave to cool naturally if you have time.

Small Metals Workshop week 2

In the morning we learned to use the small spot welder for joining thin sheet steel or steel wire/rods up to 1.6mm thick. Anything larger needs to be done with the big spot welders in the downstairs metal workshop. In the afternoon we learned copper annealing, which is the process of heating copper to a point where it glows cherry red, then cooling it rapidly, to make it more malleable and easier to cut.

When using the spot welder, stand to the side to avoid sparks and never use with copper as it will stick to the electrodes rather than welding pieces together. To straighten any kinks out of wire, use the pulley tool to stretch, pulling the wire back and forth (see 1st photo). Alternatively, for circles wrap tightly around suitably sized pipe or straighten manually by pulling taught or teasing it straight.

When annealing, heat the copper evenly with a blow torch on a fire brick until it glows cherry red, then using tongs plunge into cold water. This will make the copper black, but easier to bend, cut and work with. Small shapes can now be cut out with snips, or a small metalwork coping saw if more detailed shapes are required. Should the metal become tought to work with again, repeat annealing process. The black can be removed by soaking in pickle solution (various chemicals available but many websites suggest using a vinegar & salt solution) or can be scrubbed off afterwards with wire wool depending on your desired finish.

In this instance once I had cut out my shapes, I wanted to add holes, so I tapped the points where I wanted them to be and used the big drill to make tiny holes. I then used the hand drill to make them larger and  used this wooden bracing contraption to keep the copper still and my hands out of the way. All rough edges then needed to be filed – remember to clean the files with the wire brush after use.

My first day of workshop inductions today! I have 3 Tuesdays in the Small Metals workshop, followed by 3 Tuesdays in the Big Metals & Woodwork workshop, then finally 3 Tuesdays in Ceramics.

Today we started with Pewter Casting and I need to type up what I learned or I will forget!

Plaster Cast Mould Pewter Casting

• Make a large block of plaster in a pop bottle or the like, leave to dry completely & saw into small suitably sized blocks. Sand down and scrape the surface of the block until there are no grooves and you have a perfectly flat surface to carve into that Pewter won’t run out of.
• Carve in your design with tools. Make sure the pouring funnel is about an inch wide and half an inch deep – plenty of room to pour the pewter in.
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• Dust the finished carving with talcum powder.
• Place a piece of wood on top of the carved side, making sure it is higher than the top of the funnel you have carved and clamp on either side (not in centre). Put top of clamp on plaster & screw up against the wood. Clamp tightly but not so tightly as to break the plaster!
• Place clamped mould in sand bath, making sure that it is at a bit of an angle.
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• Heat pewter in crucible. Hold Pewter with pliers in left hand and torch in right. Once you have sufficient melted pewter, put stick down on heat proof pad, pick up crucible by handle and, whilst still heating the pewter with the torch move over to mould and pour in. Put down crucible on heat proof pad and turn off torch.
• Test Pewter has set by tapping the top with an instrument and wearing heat resistant gloves unmould. Pewter should be cool after 5 minutes.

Flask Mould Pewter Casting

• For a 2d design, draw your design on a 6mm piece of wood that will fit in the flask mould. For a 3d design, you can draw a relief design over 3 layers of 2mm wood. Cut out designs with a hand saw leaving a funnel or sprew at the top to pour pewter into.
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• place wood cut out on half of flask and tickle with talc. Place other half of flask on top & clamp tight, making sure the funnel on the flask matches up with the sprew cut in the wood. For detailed designs you may need to scratch in air channels.
• Place clamped mould in sand bath, making sure that it is at a bit of an angle.
• Heat pewter in crucible. Hold Pewter with pliers in left hand and torch in right. Once you have sufficient melted pewter, put stick down on heat proof pad, pick up crucible by handle and, whilst still heating the pewter with the torch move over to mould and pour in. Put down crucible on heat proof pad and turn off torch.
• Test Pewter has set by tapping the top with an instrument and wearing heat resistant gloves unmould.
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Bangle Mould and Delft Sand Pewter Casting

I didn’t actually have a go at the bangle mould casting, but watched the demonstration. As such, best check with Martin when actually having a go to make sure I didn’t miss anything. Always easier to remember when you’ve actually done something.

• Take the bottom bangle, place on a flat and moveable tray e.g. tin lid. fill with delft sand and compress with a small hammer. Make sure you leave room for the joining of the top and bottom bangles. Has to be delft sand, which is oily, not dry sand. Compress so that it won’t fall out of the bangle when you pick it up, but so that you can still push the item you wish to cast into the sand deeply enough. Leave object in sand. This is so that when you indent the other half of the bangle, both sides will line up.
• Repeat process with top half of bangle, placing top half on top of bottom half to complete the 3d impression.
• Take top half off again, remove object and tickle both sides with talc.
• For the top half, insert thin metal rods at the extremities to create air channels for air to escape. Then insert a thicker metal rod to create a sprew. Turn the bangle upside down and using a stanley knife, cut a cone to enlarge the sprew to make a good sized pouring funnel.
• Clamp the 2 halves of the bangle together.
• Place clamped mould in sand bath.
• Heat pewter in crucible. Hold Pewter with pliers in left hand and torch in right. Once you have sufficient melted pewter, put stick down on heat proof pad, pick up crucible by handle and, whilst still heating the pewter with the torch move over to mould and pour in. Put down crucible on heat proof pad and turn off torch.
• Test Pewter has set by tapping the top with an instrument and wearing heat resistant gloves unmould. Make sure you don’t waste any of the delft sand as it is expensive and can be re-used.

Once the pewter is cast, you can add the finishing touches – remove the sprew and any other rough edges with a metal hand saw or a file, etch designs into it with tools, buff to a shine, make holes or loops for attaching to keyrings or necklaces etc…