Talk Composites - The Forum for Advanced Composites

Beginner to casting and mould making for sculptures and jewellery

http://www.talkcomposites.com/Topic24839.aspx

By Helenegg - 1/5/2018 1:46:46 PM

Hi , I make heart sculptures in fired clay and polymer clay including for jewellery. I am interested in creating clear resin versions with the addition of glitters and possibly pigments. Looking at the products available I guess I will need to make a silicon mould first and then use a clear resin product. My sculptures can be as large as around 11cm wide by 7cm deep and maybe larger. All pieces are fired and baked. I have also considered perhaps making wax versions if necessary for casting. I have looked at the videos for making a mould and using resin which are helpful and read the forum and see that there is a new product out soon that does not go yellow over time. I would welcome advice on the following:

1) Which resin and silicon mould products would be the most compatible and easy to use for a beginner to create nice clear glass like and shiny pieces with no stickiness?

2)  Will I be able to cast the larger pieces in one go  or will I have to do it in stages so it will set in the middle?

3) The sculptures have rounded bottoms so how best can I structure the mould to allow for this? Will I have to pour into the bottom of the shape so that it extends out a bit then sand and polish? How much space do I need around the piece in the mould?

If you have any other useful tips that would be great!
I look forward to advice and getting started!
Many thanks 
By Helenegg - 1/8/2018 10:32:07 AM

 
Warren (Staff) - 1/8/2018 9:37:55 AM
In an ideal world, you can degas the silicone in a degassing chamber but for simple casting it is not essential.  Just "stretch pour" instead to remove the big bubbles.  Stretch pouring is pouring from a height as a thin trickle of silicone to help remove the bubbles.  If there is fine detail, you can also brush the silicone into the detail ensuring no air is trapped, then pour the main silicone pour.  That way there is no air on the mould surface where it matters, but the rest might have bubbles.

Thanks Warren actually bubbles are fine for my pieces as they might add an extra dimension ! There is no fine detail either just smooth rounded shapes. Many thanks