Incompatible

Different glasses have different CoE e.g. Bullseye and Effetre. When these glasses are heated up and then allowed to cool the outside of the glass cools quicker than the inside. This is what leads to glass cracking and the failure of the bead. If you use 2 different glasses that have different rates of expansion then this proces is magnified and the incompatability will definitely lead to the demise of the bead!