Glass Painting Enamel Questions

I am experimenting with glass painting by screen printing onglaze enamels and then firing the glass. Is there any glass enamels you can recommend that can withstand high firing temperatures and have a CoE for working with Bullseye glass?

Milly's answer:
This is a very good question, given the complexity of glass compatibility issues.
The good news is that there's no compatibility issues with onglaze enamels, as long as they are applied thinly. Screenprinting is perfect - you can't get thinner than that!
To explain further: the term 'enamel' is a broad term, and covers two types of glass paint:
1. The type you're working with, which are a mixture of powdered clear glass and highly coloured oxides (eg Ferro, Heraeus)
2. Powdered frits that are simply crushed coloured glass ground down to powder form. (eg Bullseye, Thompson and Schott Artista)
Because type 1. includes intensely coloured oxides, you don't need a thick layer to get good results - especially with opaque onglaze enamels - and so, thinly applied, this type of enamel is compatible with any glass.
With regards to temperature, type 1. enamels are either low or high-firing - ask the manufacturer which range to choose from. The high-firing ones are nearly always opaque, although the blues can be transparent if fired thinly enough. I use Ferro - their Sunshine Series is high firing - and Heraeus. Reusche are supposed to manufacture high firing transparents, but I haven't tried them.
Last thought: transparent enamels contain lead and should be used with care.
I hope that answers your questions on glass painting.

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