I’m experimenting with glass-to-metal hermetic sealing using spray-dried glass powder and Kovar components. As part of the process, I’m preparing glass preforms using PVA and forming small discs with a center hole for pin placement.

Binder Ratio I’m using 5–10 wt% PVA binder relative to glass powder. Is this appropriate for good green strength and burnout?

Binder Type Currently using partially hydrolyzed PVA (~88%, MW ~85k–124k). Would fully hydrolyzed PVA improve or weaken preform quality?

Mixing Method Using wet mixing of PVA solution with glass powder, followed by air/oven drying. Is this preferred over dry mixing or dry pressing for small preforms?

Shaping and Hole Formation Planning to press the paste into a mold and insert a pin or create a hole before drying. Should the hole be formed pre-drying or post-drying (e.g., drilling)? Which method gives better stability and alignment?

Drying Process Drying preforms at 150 °C for 30–60 min. Would a slower drying process (e.g., 80–100 °C for a few hours) reduce cracking or warping?

I’d appreciate insights from researchers who have worked on similar glass frit or ceramic preform systems.