In order to blow glass into a metal structure, the structure must be straight, not curved, and the minimum diameter should be 3cm. For this reason, the glassblowing technique is not ideal for a jewellery collection, as I am very limited in size. This technique is more suitable for larger objects.
Epoxy filled balloons allow you to make very large bubbles and smaller objects. Epoxy is also much lighter than glass. Transparent epoxy is not as clear as glass, it also has bubbles and the balloon is difficult to remove, sometimes impossible. But the metal stays clean and could be coloured. The glass looks very clean and perfect, many different colours could be achieved. The metal is exposed to incredibly high temperatures, so it darkens. It is not possible to clean the metal afterwards with the glass inside without making the glass dirty (polishing is not possible). The glass blowing technique makes it possible to create beautiful objects, but they have to be quite large and straight, it is not possible to blow the class in round tubes. That's why the glass blowing technique does not allow to make small objects in different shapes, while the balloon vacuum epoxy technique does.