Whether you have past experience of silicone moulds and polyurethane casting resin or are a complete newcomer to these exciting materials, Easy Composites' Silicone Mould Resin Casting Starter Kit is a brilliant way to get everything you need in one great value package.
Using this kit you can take just about any original part including RPG figures, small sculptures, figurines, scenario models or even engineering components and use them to create a flexible silicone rubber mould of the original part.
With the original part removed from the silicone the mould can then be used to create accurate and detailed reproductions of the original part by pouring mixed casting resin into the mould. The resin included in the kit is a very easy to use Fast Cast polyurethane resin which will flow easily into the fine surface details of the silicone mould and then cure quickly (within an hour) to a strong plastic copy of the original part.
The number of uses for the Silicone Mould Resin Casting Starter Kit are almost limitless. Some of our customers use the kit to make a whole army of modified Warhammer characters whilst others use the process to reproduce simple plastic parts that you just can’t anymore. Engineers can use the process as part of their rapid prototyping work whilst artists can easily make copies of their original work as samples or demonstration pieces.
Included in the kit is everything necessary to first create a silicone mould and then make plastic (polyurethane resin) castings of the original parts. No additional equipment or supplies are required.
Full details are included with the kit but for simple mouldings the process can be summarised as follows (more complex shapes will require slightly different techniques):
1. Position the part in a 'set-up' box
Position the original part in a 'set-up' box that will hold the silicone rubber around the part whilst the rubber cures. For small figures or parts the mixing cups included in the kit make suitable set-up boxes. For larger parts use one of the included plastic set-up boxes. The part can be suspended from above or bonded to the bottom of the box.
2. Mix a quantity of silicone rubber
Measure a quantity of silicone rubber sufficient to fill the remaining space in the set-up box with the correct amount of catalyst. The silicone and catalyst are mixed at a ratio of 2-5% catalyst
3. Pour the silicone rubber into the set-up box
To ensure a good surface finish on the parts that are made using the mould it is important to ensure that the silicone rubber does not contain any air bubbles.
In a professional environment this would be achieved through the use of a vacuum de-gassing chamber and so without this equipment we need to firstly be careful not to mix air into the silicone in the first place and then secondly using a process called 'stretch pouring' to remove any trapped air.
Position the set-up box either on the floor or on a low table and then very gently and carefully pour the mixed silicone into the lowest point of the set-up box. As the silicone pours it will stretch out to a very thin 'stretched-out' trickle of silicone and in doing so any trapped air will be forced to the surface and out of the silicone. Done carefully this process can be highly effective at the removal of air from silicone and yield excellent results.
4. Allow the silicone to cure
The condensation cure RTV silicone included in the kit will take about 24hrs to cure at room temperature and average humidity.
5. Remove the original part from the silicone mould
Once the silicone has fully cured the resulting flexible rubber block (containing the original part) can now be removed from the set-up box.
Depending on the shape and complexity of the part it may be possible to simply stretch the mould slightly and pull the original part from the mould. Other shapes will require that the mould is cut open to remove the part.
If necessary, using a sharp scalpel blade the rubber mould can be carefully cut through into two halves (which will fit back together perfectly) and the original part removed. The mould should be flexible enough to allow extraction of the part.
If the mould has been cut into 2 halves these halves should be taped or otherwise held together in their original shape before using the mould in the next step.
6. Mix the casting resin
Mix enough Fast Cast Polyurethane Casting Resin to fill the new mould. The Fast Cast resin included in the kit uses a convenient 1 to 1 mix ratio.
When mixing, it is again important to avoid unnecessary air inclusion.
7. Pour the mixed resin into the silicone mould
Carefully pour the mixed resin into the lowest part of the silicone mould. Continue pouring into the same place and allow the resin to fill up the mould.
8. Allow to cure and then de-mould
The Fast Cast resin will cure and be ready to de-mould within an hour. Once the resin feels fully hardened the new casting can be removed from the mould (separating two halves of the mould if necessary).
The mould can now be used to create many castings in a single day!