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.
- 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.
- 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.
dav- 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.
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…
clairemaloney 