We recently had some interesting questions on Facebook about casting and mould making basics with glass. Here are the answers Simon gave, which I hope you will find useful too if you are considering glass casting. This customer wanted to cast small historical replicas in blue glass like those in the image below:
1. What moulding composition would you recommend to cast mould forms in which to melt glass? We would like to use it several times.
A: The best mould release for this is Primo-primer.
3. What kind of blue (not completely transparent) glass would you recommend to express all the details on the best way? Powder, sand, a liquid variant, pasty mixture?
A: From your image I would recommend fine frit in True Blue or Light Sky Blue, this will give you an opaque blue. For more transparency you can use larger frit sizes or billet.
4. Will you provide us with firing programs?
A: For the fine frit you can use the following firing so long as the pieces are no more than 25mm thick.
- 222C to 804C and hold for 10 minutes
- 999C to 482C and hold for 1 hour
- 83C to 371C and leave to cool to room temperature
5. Will it be necessary we to glaze the product?
A: This will not be necessary.
If you have any other questions about casting and mould making, feel free to post a comment and we will try our best to answer!