Trial #3 - Copper grid with white non-reactive glass

There seems to be a couple of attributes that are consistent when using copper. To date, in everything that I have fired using a clear glass cap over any form of copper (foil, heavy foil, grid, etc.) the copper turns crimson.  On close inspection, the area around the edges of the copper contains more bubbles than any other area.

Trial #3 - White non-reactive glass with 3 stars cut from copper grid, and topped with clear glass post-kiln firing.

The air bubble pattern in the grid copper is fascinating.  Look below in the star grid.  Inside almost every grid within the copper mesh, there is an air bubble - each looks like it is trapped by the walls of the grid.  Notice, also, on the lower right hand side, there is a larger air mass that runs the length of two side of the star points.  When copper heats, it not only chemically changes to result in a different color, but it is also releasing something (I am assuming O2,) as well. 

Trial #3 - White non-reactive glass with close up  of one star cut from copper grid, and topped with clear glass post-kiln firing.

In another example, I tried laying a clear 2mm stringer perpendicular to the copper material, and run it to an outside edge.  It appears as though the released gas follows the path of the stringer.  For smaller pieces, less gas appears to be trapped in the fused piece when using the stringer and running it to the outside edge.  In larger pieces, the gas appears to have traveled along the stringer and made it about 2 inches. 

Trial #3 - White non-reactive glass with close up on one star cut from copper grid, and topped with clear glass post-kiln firing.

That would suggest to be that there is a time factor involved.  At a specific interval of time, the glass "above" the stringer slumps down (impact of gravity on a fluid,) and seals the escape pathway before the gas has had a chance to escape.  The time factor/temperature relationship must also play in to the trapping of gas in each of the non-copper grid openings (notice the regularity of the pattern of trapped air in the close-up of the copper grid above.) 

After additional experimentation, I think it would be interesting to further establish gas-release patterns when using copper and use that information in the design process.  For now my main question is, "....where do they sell fine copper mesh/grid material??"  Any ideas??