North Brisbane Lapidary Club

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Until the 1.5m social distance restrictions are relaxed numbers attending the club will be restricted, therefore bookings are essential. 

Faceting Competition

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 *****     Congratulations to Brenda on her wins in the Cairns Show Lapidary Competition    *****

The criteria was a Standard Round Brilliant, with faceted girdle design in any colour quartz. Competing with 19 other entrants she achieved 1st and 2nd prize for her work. Check out her scores they are amazing.

Brenda thanks her expert mentor Vicki for all the help over the last couple of years.

1940’s Brooch

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by Thierry

Enhancing a 1940’s Sterling Silver Brooch – The original Brooch had a Green Cut Glass Stone with a Golden Mirror backing. The patterns were covered in black paint of a sort and the Brooch took a bit of bashing. I first removed the back paint and restored it to shape, to discover a delightful and intricate Brooch. The Green Cut Glass didn’t do it justice, so I cut a piece of Maryborough Chrysoprase as a Cabochon. The Apple Green colour of the “Australian Jade” adds Charm and Elegance to this Sterling Silver brooch. A Christmas present for my Mother in Law … Why on Earth should I be so nice to her?

Topaz Ring

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by Thierry

"The Brilliance of a Topaz" or "The Art of Fitting a Round Gemstone in an Oval Ring!"  - A rather humble but elegant Lost Wax Casting Ring designed for an Oval Gemstone. I had the perfect stone for it! A brilliant cut blue Topaz, but it was round! So I carefully reformed the ring to accommodate the Gemstone. I did set the Topaz low so to enhance the ornate design of the ring, but also to give it this magical brilliance as if the ring was alive. Cast by Joyce, embellished by a 'Frog'!

Butterflies

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by Carol M

I have been playing again. This time using silver foil and enamel paints.

It started with a demonstration of sawing/piercing to some of our newest converts to the Silver Smithing area.  I thought I would demonstrate that sawing can be used not just as a means to cutting links for making chains.  I had seen some beautiful enamel work on Facebook with leaves and butterflies so thought I would give a butterfly a try.

I started by using my Wildlife of Greater Brisbane book to find a butterfly with the colours I thought I could reproduce, especially some of the transparent colours that can be achieved on silver foil.  See the Meadow Argus (pictured above). I then drew a diagram with a plan of the colours I would use and how that would relate on the copper. I then used a flux on the copper before placing silver foil on the areas I wanted to shine.  The rest was wet packed and finally enamel paints on the final layer.

Most of the work was torch fired, because I was impatient and doing it at home, but ideally as the piece was so big it would have been better kiln fired.  It was hard to keep the heat on the whole piece.  The last fire I did do in the kiln just to give it the gloss finish.

Conversion of a Brooch

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by Thierry

Brooches tend to stay in drawers, unloved nowadays, but many of them can be adapted to wear as pendants by making some simple inserts.

Here is an example of two inserts. A chenier and rabbit ears bail fitted over the pin; and a square with a standard bail.

Chains

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by Mary

Chain variations that Mary has worked on since the President’s Challenge, a bracelet and necklace.

Bezel set ring

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Made by Lisa

Lisa is one of our budding beginners, who has now completed all the beginner projects, the last one being this ring.  There was no bezel wire so she chose to go ahead with the stepped bezel making a feature of it.

I am really looking forward to seeing what she chooses to make next.

Stained Glass part 2

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by Carol M

So this is my second attempt at Plique-À-Jour enamelling. Not good enough to give to my friend for her 60th as I had planned, but ending up as an addition to my ever growing collection of earrings.

I started out laying the piece's flat using the mica sheet, as with the test samples on the previous post, and filling in the areas with enamel. The enamel still sticks to the mica sheet and has to be then cleaned up, this led to cracks or the enamel falling out completely. I think maybe using 0.5mm fine silver was too thin, not giving enough thickness for the enamel to adhere to.

I then switched to the suspension method, using trivets and only very small amounts of enamel in the areas to be enamelled, building the layers very gradually. The first firing I let the kiln get too hot as the enamel dropped out, but I persevered being very careful not to let the kiln temperature reach over 785°C on subsequent firings.

This is very time consuming and I think I have spent at least 12 hours on these earrings, I am afraid to say this technique will have to wait until I have more time before trying again!

 

So I then tried the Champlevé technique, where areas of silver are either etched away to allow enamel to be laid into them, built up until they are the same height as the silver.  Instead of etching I tried another first for me and having pierced a design in a piece of silver, I fused it to a base plate.

Fusing, again a technique to be practised, there is a fine line between fusing and melting. I was getting better but as you can see there is some reticulation. The idea behind fusing is that you get the very shiny surface as a base for the transparent enamels but I have also read that by texturing the base it gives an interesting look to transparent enamels.  In this case I went with the texture.

Filling the areas with enamel was a much simpler solution than the Plique-À-Jour, but the enamels have still not come out as transparent as I was hoping.  Not sure if this is due the textured base or not freshly cleaning the enamel.  Maybe there will be a part three to this post ......

Feldspars

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by Ray Wilson

Feldspar is the name of a large group of silicate minerals that can be found in igneous, sedimentary, or metamorphic rocks.  Feldspars are commonly used in lapidary.  The coloured varieties make great cabochons and the clear type that can be found at Hogarth’s Range (west of gold coast) or Springsure Qld. can be faceted.  Feldspar has a hardness of 6 on the Mohs scale, so not as hard as quartz or agate.

Feldspar is an important industrial mineral being used to manufacture plate glass, container glass, ceramic tiles, plastics and other products.

Anyone interested in cabbing some Spectrolite see Carol South as the club has some material for sale.

Labradorite – a variety of plagioclase Feldspar.  Named after a location in northern Canada.   Labradorite displays an iridescent optical effect (or schiller) known as labradorescence.  Most material now comes from Madagascar.

The cause of this optical phenomenon is lamellar structure (very thin plates or flakes) with light being diffracted.

Spectrolite – A variety of plagioclase Feldspar found only in Finland.  Spectrolite is a trademarked name for this material.

Spectrolite from Finland
Labradorite from Madagascar

 The difference between Labradorite and Spectrolite is mainly that the background material in Labradorite is clear or translucent while Spectrolite the background is black.  Spectrolite tends to have more vibrant colours in reds, purples, and oranges.  Labradorite is generally vivid blues and yellow/bronze colours.

Moonstone – an orthoclase Feldspar that shows a pearly sheen or schiller.  This is the basis of the name moonstone.  Its name is derived from a visual effect, sheen or schiller (adularescence), caused by light diffraction within a micro-structure consisting of regular  lamellae.

Sunstone – is a plagioclase Feldspar that has either a hematite (iron stone) or copper inclusion.  Sunstone fund in Kong Bore Northern Territory has a hematite inclusion and appears as a series of rainbow-coloured specks rather than a schiller as in Labradorite or spectrolite

Kong Bore Sunstone

One variety of sunstone also found in the Northern Territory is a very rare Rainbow Lattice Sunstone

Rainbow Lattice


Oregon Sunstone from Oregon in USA has a copper inclusion which gives the stone a coppery coloured schiller.

Oregon Sunstone

KT-100 Mini Magnetic Tumbler

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Views from Thierry

You can get these 100mm magnetic tumblers on Ebay for about $300, supplied with and acrylic bowl, and 100 grams of 0.3 mm x 5 mm stainless steel pins. You still need to purchase some Tumblex Gleam powder ($20 for a jar at AJS).

Italian Brand name made in China. The tumbler is basically a magnet stirring the steel pins in the acrylic bowl.

These machines are perfect for tumbling intricate textured pieces and chains as the tiny pins can go and burnish every spot, unlike a traditional steel shot burnisher as the shots are much bigger. But these machines have a few quicks and drawbacks

  • Machine as supplied
  • Cracked Bowl
  • Machine Settings
  • You still need to purchase some Tumblex Gleam powder ($20 for a jar at AJS)
  • The acrylic bowl is of poor quality in my view, with the base cracking and leaking over time. Sourcing a replacement bowl at a reasonable cost is virtually impossible. So, I use a Pyrex Simply Store 2 Cup Round Storage Dish (11.4cm x 5cm) – $10 at BigW
  • The 100 grams worth of pins is ample enough, but sourcing additional pins is difficult in small quantity
  • The supplied pins look clean, but they are very dirty from the manufacturing. I tumble them twice before tumbling any jewellery pieces
  • You must leave the pins in a Tumblex Gleam solution to prevent any oxidation when not in use
  • You never ever leave the pins after use on the machine or your pins will get magnetised and become totally useless
  • Cleaning the pins is not easy their tiny size, I gently clean them under running hot water
  • As they clean/polish much more in details, chains notably, the solution gets dirty faster than a traditional burnisher. I clean and replace the Tumblex at every use
  • You will end up having pin marks on your pieces if you burnish for too long. 30 minutes is enough or 10-15 mins for recleaning a chain
  • Rinsing the Pins
  • Tumblex and how much you fill
  • Machine in use with Glass bowl

So, this is my method for using it, you may decide on your preference once you start using it

  • First use, clean the pins twice before use
  • In the glass bowl, put the 100 grams of pins, a quarter of a teaspoon of Tumblex Gleam and about 15-20mm of water in the Pyrex bowl. No need to stir the powder
  • Put your pieces (they should have been cleaned up to start with)
  • Close the lid and vacuum seal the lid.
  • Set the speed control to 4 – Maximum. I never bothered trailing different speeds
  • Set the green button to oscillate – it will change direction every couple of minutes
  • Put the glass bowl on the unit
  • Adjust the time control – 30 mins is ample
  • Switch power on
  • Keep an eye on it, to make sure to remove the bowl once finished
  • Once finished, wipe any water spill on the unit
  • Open the lid gently, place the bowl in a sink, gently run hot water over the lid into the bowl to rinse it in case there is some pins stuck under the lid. Gently run the hot water over the bowl to rinse the liquid, gently moving the media and pieces to dislodge any dirt. Once the water is clear, remove a piece at a time and rinse over the bowl to drop the pins back into the bowl. Once finish remove the excess water and leave 15-20 mm of water in the bowl. Collect any runaway pins back into the bowl. Add a quarter of a teaspoon of Tumblex Gleam. Dry the lid and vacuum seal close the bowl. Store on the side of from the machine (not on it!)

Overall an excellent machine if you use it properly. Perfect for home but not ideal in a club as you need supervision to make sure people don’t overfill or leave it on the machine after use.

I use it all the time at home and it is a god send, notably for burnishing chains and castings. I first clean my pieces in an ultra-sonic cleaner and/or use a toothbrush and dishwashing liquid.