REAL bubbles in kiln glass

Not sure what you call large. Place a clear chip between the layers where you want the bubbles. Watch at your top temp so the bubbles don't break or get too near the surface.

The traditional way of making bubbles is baking soda (bicarbonate of soda) It can be used with molten glass. The amount of gas and therefore the size of the bubble depends on the amount of soda and in this situation clearly the size of the bubble depends on how much gas leaks out during the relatively slow heating process. You will have to experiment.

Thanks Mike and Jack for your suggestions!

Using baking soda between two layers of glass, how do I go about it? Would I mix it with a bit of water? I am not blowing glass, it´s kiln-worked.

Deet

Do some tests with a tiny dab of baking soda and see what happens. You could make a solution, put a drop where you want a bubble. let it dry before putting the top layer on. If the bubble is too small/large use a more concentrated solution or more drops, allowing drying time between drops. I've heard there are bubble compounds available but they shouldn't be necessary.

How about if we somehow give you the bubbles that I don't want in my projects.

I like that last idea - "Now opening - the Bubble Exchange - lookup your bubbles by category (actual sized bubbles by diameter and height coming soon. List your own bubbles - all bubbles must be transportable, any bubbles made of biodegradable soap or other transient substances will be deleted automatically."