How to make a silicone rubber mould using a toy train track as a model. Prince August Hobby Casting.

This project covers how to make a silicone rubber mould of a toy railway track. The track itself is plastic. Silicone Rubber comes in two separate tubs that will need to be combined to make the rubber for the mould.
We are also using modelling clay to create the base for the initial mould as well as the containing walls.
The use of a vacuum chamber is important to remove air bubbles that naturally get trapped when mixing the rubber together. This however does not take long and when completed the rubber is ready to pour. You can use this rubber without a vacuum chamber and if an air bubble is a problem you can fill that air bubble with silicone later. Air bubbles only matter if they are attached to the casting.
This demonstration was done over several days. We leave each mould side for about 24 hours to properly cure before removing the walls. This makes sure the rubber is completely cured before we put any metal into it.
We use Model Metal in this demonstration but other metals would also work, provided the temperature was slightly adjusted. Model Metal is one of our brand alloys that consist of Tin, Bismuth and Lead. Alternative lead free alloys include 5-Star Metal and 6-Star Metal.
The metal bars are melted in our Solder Pot. This is a very easy to use device that allows you to melt in a basin up to 1kg of metal. The steel ladle can be used to scoop out metal as shown in this video.
Cooling times for metal vary depending on the scale of the figure and how bulky it is. Adult supervision is always required if casting with minors. Allow at least 10 minutes when dealing with large moulds like this before opening the mould otherwise the metal may be distorted, weakened or broken at any vulnerable spot as it will be soft. After about 10 minutes you should be able to open the mould. Give another 5 minutes and you should be able to remove the casting safely enough. Never try to rush the cooling process.
This project incorporated a custom job so we do not supply the track in this video. We offer custom mould services on our website.
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[@TheRich107]

This looks great, thank you for making this video and talking it through so clearly.
I didnt know this was possible as a hobby and by hand. With a 3 year old making traintrack hits home for me.
What is model metal actualy made from?

[@princeaugustcasting]

Tin, Lead and Bismuth.

[@waywardmedia4491]

how many castings will the silicone mould do

[@princeaugustcasting]

It varies depending on the complexity of the master figure and what metal you are pouring in. You will get dozens perhaps. The rubber is more delicate than our standard rubber. Normally make the metal master and then convert it to a full black rubber mould by sending it to us. A direct press for a strong black rubber mould is a service we can provide.