Beeswax and moulds
You will need
Item to be moulded
2 part silicone rubber
Small piece of plywood
Scales 0.01 g ideal
Water (to work out how much mould)
Gloves for use with 2 part mix
suitable item to be moulded -the model
variety of elastic bands
a IR thermometer is also useful
Some way to melt beeswax
A few things are important in making a mould. Beeswax is a fantastic material for casting, but it will take on any imperfections on the object being moulded. So, ensure that the item being moulded is as clean as possible.
So, what follows is how I make my moulds, please note that there are many ways to make moulds, this is just one of them.
First, obtain a sheet of thin ply wood to form a sturdy base for the moulding activity, add a thin layer of plasticine using a rolling pin to flatten out, it doesn't have to be perfect.
The next step is to position the item to be moulded in to the centre of the plasticine base. A little time is always worth spending on thinking about the orientation of the mould. The key thing to remember is that with every moulded object there is always the side that the beeswax is poured into, this creates a rougher surface and should be ideally hidden from sight. So, with this in mind, place base of the item to be moulded directly onto the plasticine base. This will be the end that the beeswax will be poured into.
Next, is the fun part, make a surrounding collar of thin plasticine slightly higher than the top of the mould by rolling out sheets of plasticine and placing around the item. The idea is to create a watertight container that the silicone stuff will be poured into. It needs to be a little wider than the model. The wider it is, the more silicone stuff you will use, this equals more expense. Aim for around 1 cm on small objects and 2 cm on larger objects.
Next step involves adding water to check for leaks in the plasticine, if the amount of water is weighed on a kitchen scales then the amount of 2 part silicone stuff required is the same. Ensure that there are no leaks with the water, if there are, the 2 part mix will leak out too! Empty out the water leaving the plasticine to dry out.
So, now mix up the appropriate amount of the 2 part mix using the 0.01 g scales, accuracy is reasonably important. Getting the wrong amounts means that the mix will set faster or slower than required. I would suggest that the fast setting mix is used anyway, this takes 5-10 min to set.
This mix needs to be well stirred, following the instructions supplied. You will only have a few minutes to poor into mould, so make sure everything is at your fingertips.
Poor into the mould slowly, pouring in one place only, allow the liquid to flow around the model naturally. Keep pouring until all is used. You should have a min of 1 cm of 2 part mix covering the model.
Now, all you can do is wait. The manufactures of the 2 part mix will state how long the stuff takes to set.
Once set the surround of plasticine can be carefully peeled off, once all is removed lift off the set mould from the palatine base. Obtain a sharp craft knife (not kitchen!) the knife needs to be razor sharp and thin, this allows a perfect cut in the silicone, easier to align the mould afterwards -see later. Using the knife cut through the silicone to the model inside, start at the top and cut in one motion going down towards the bottom. Stop before the bottom though, this gets better with practice. using the knife again, repeat the cut on the opposite side of the mould. I find that aligning the cut to any edges produces a better mould.
Once cut the model inside can be carefully extracted. This leaves the mould almost ready for use, finally clean using water and fairy liquid, make sure any plasticine has been removed.
The mould is now ready for casting beeswax into the shape of the original model.
So, now onto melting beeswax. Beeswax is a delicate material, to hot and it discolours, it's also flammable too ! Heating needs to meet the following conditions, gently and temperature controlled. One way is to use an old food steamer, this has the advantages of limiting the temperature to 100C and in my mind a very gentle way of heating compared with some other methods. Think carefully how you will melt beeswax, safety should be taken seriously. Overheating and having a wax fire is not safe!
I use a food steamer with a 2 L plastic jug inside. Other materials can be used for the jug, but my preference is plastic as it is easier to handle when hot. Note, that some cheap plastic jugs will be degraded by the continuous heat of a steamer.
Setup and melt a suitable amount of beeswax.
While the beeswax is melting prepare the new mould.