Mould Making Material for Resin Jewellery

Using do-it-yourself or ready-made moulds to make resin jewellery expands your horizons. Almost unlimited shapes and sizes of ready-made jewellery moulds to make cabochons, pendants and earrings are available to add diversity to your jewellery designs.

Moulds come in many shapes and sizes and are available ready-made with both plastic vacuum formed materials for simple shapes and surfaces or do-it yourself moulds made from rubbers such as silicone or polyurethane, to provide extra detail to the surface of your finished piece.

Types of ready-made moulds

The epoxy, polyurethane and polyester resins commonly used to cast resin jewellery require the correct type of plastic moulds to be used for success. The usual plastic moulds used to cast plaster and similar materials are not suitable instead special polypropylene and polyethylene resin moulds are used. These moulds have a distinctive greasy surface feel to them and enable easy release of resin jewellery products.

For beginners we recommend that a release agent be used. This guarantees easy release from the moulds and gives additional length of life to the mould. With experience you can selectively omit the use of a release agent with the result that the resin is released from the mould with a more brilliant finish. Test with a small project before embarking on any major production.

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Do-it yourself resin jewellery moulds

I am often asked for simple straightforward instructions on how to make jewellery moulds and how to go about making a mould of a simple flat backed object such as a pendant or a badge or even perhaps of a wall plaque. The techniques for making any of these objects is basically the same.

Silicone resin jewellery moulds can be made either by brushing or by pouring. For flat backed objects it is easier and quicker to make the mould by either using a pouring silicone or using the new silicone putty.

How to Make a Silicone Mould for Resin Jewelery

CraftSil Silicone comes in two parts, the silicone and the hardener. The first step in making a mould is making a mould box in which to make the mould. The instructions for doing this are contained in the article “Making a Mould Box”.

For the purpose of these instructions we are going to make a mould of a flat backed ornament.

  1. Adhere the ornament to a flat and level sheet of plastic or glass using a glue gun.
  2. Using a then ribbon of Plastelina clay fill in any areas underneath the ornament with the clay. Smooth the clay to prevent the silicone from getting underneath the ornament.
  3. Place a mould box around the ornament, using either one of the methods given in the mould box article. For these instructions we will use the top part of a plastic cup cut in half.  
  4. Adhere the mould box in place by using a glue gun. Smooth Plastelina clay around the base of the plastic cup to prevent leakage.
  5. To estimate the amount of silicone we will require, fill the plastic mould box to a level 1cm above the top of the ornament with dry rice. Water could be used but would require time out for drying. Pour the dry rice out of the mould box into a measure to give you the volume of silicone required to make the mould.
  6. As silicone is measured by weight, place an empty measuring container on the scales and then tare the scales to zero. Pour in a similar volume of water to the dry rice and see how much it weighs. This will be the weight of silicone required.
  7. Weigh out the silicone and hardener required in separate containers.
  8. Pour the hardener into the silicone and mix thoroughly until no streaks are showing. Incomplete mixing will result in pockets of non-cured silicone which will never harden to form the mould. Scrape the silicone mix from the sides and bottom of the mixing container. For best results we recommend pouring into a clean second mixing cup to ensure that we cast the mould with a properly mixed silicone.
  9. The next major problem is air bubbles, the bane of our existence. In mixing the silicone a considerable amount of air was incorporated into the mix. The professional way to eliminate these air bubbles is to use a vacuum pump and chamber. Instructions on using this method is given separately.  However for over 10 years we have been making silicone moulds using the thin stream method with great results.
  10. Stand with the silicone mixing cup about 1 metre above the mould and aim to have the thin stream of silicone enter the mould at its lowest point away from the ornament. This takes a steady hand and an accurate eye, but the air bubbles are broken once the thicker stream of silicone leaving the mixing cup thins out to be so thin that air bubbles are broken and disappear. The silicone gradually flows over the surface of the ornament and fills the mould with no problem with air bubbles. Pour in a draft free environment.
  11. Leave the rubber to cure overnight and then remove the mould.

Containers in which to make do-it-yourself moulds

As with any poured mould the first thing we have to consider is how we are going to contain the liquid silicone around the model.

Fortunately with these smaller objects many suitable containers are to be found ready to hand. Plastic containers are suitable and come in shapes and sizes. What we want is a container that is about 1 to 2 cm bigger all around and about 5 cm taller than the model. The clear disposable plastic containers used for take-away food are ideal and come in a variety of sizes.

For smaller items we fix the model to a small board and surround it with a non-hardening clay such as Plastelina rolled out flat to about 1 cm thickness and cut and shaped to make a suitable surround. Another method is to use Lego blocks built up to the make a closed container around the model.

All of the methods require the model to be fixed to the base of the container to save it moving or floating up out of position when the silicone is poured in to the container. The model can be glued with a hot glue gun or simply press the model down on a small ball of Plastelina. This will squeeze out any surplus clay from under the model and firmly adhere it to the container base. It will be necessary to clean any excess clay from around the base with a small pointed tool.

Resin Jewellery Decorative Fillers

The use of fillers and dyes can vary the variety of jewellery that you can produce. By using clear resins transparent dyes and inclusions, beautiful faux amber, abalone, jade or opal jewellery can be made. Sandblasting clear resin gives a unique frosted appearance.

A new look for resin jewellery has been achieved with the use of dichroic glass. Stunning results can be seen by embedding small pieces of dichroic glass in clear resin.  There is an almost limitless colour and design range of dichroic glass available.

Opaque resins can be coloured by adding pigments to make faux carnelian, turquoise or jade. Unique colours can be easily made by judicious mixing of pigments.

 

Removing and finishing castings from moulds

Remove the castings from the mould by flexing the mould and gently pressing from the bottom of the mould. Any rough edges or flashing can be removed by sanding with wet/dry sandpapers under water, to smooth the rough edges.

 

Use of Dyes

One of the most beautiful effects possible using resin is that of faux amber. In nature amber has been formed from ancient pine or spruce trees. Over time plants and insects have sometimes become embedded in the resin resulting in fossil amber.

Simulation of these effects can be achieved with the use of amber dye, a little dried organic matter such as crushed dried rose petals, bits of bark or leaves and some small pieces of gold metal leaf.

This is just one of the many jewellery making effects possible with these new versatile resins.

For more information on casting materials to make resin jewellery click here: . http://www.aldax.com.au/newtechtiparticles/makingjewellery.htm

Aldax CraftSil Silicone can be purchased here.

©2016 Stan Alderson   Aldax Enterprises Pty Ltd All Rights Reserved                      BL1027

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