[Edit and Warning 12/1/2015] This did not turn out as I had hoped. The Dura Lar is too flexible, resulting in buckling/rippling and generally not lying flat on the shells. as is concluded toward the end of this thread, a thicker more rigid clear plastic sheeting is required. I have not as yet sourced such a material.
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Beginning the test phase of this new process.
To recap, last time I affixed the glitter to the Dura Lar using Triple Thick Krylon Glaze, shook off the extra glitter and glued the "rough side" to the shell using wood glue. This worked for a glass-hard surface and looked great, but the drying action of the wood glue caused a "blown up" orange peel texture to form, large-ish waves or ripples. It's also no good if I want to make some wrap for others - you can't ship it with one side open, merrily shedding glitter all the while...
At first I thought, two layers of Dura Lar with glitter sandwiched between, but then realized it's a waste of Dura Lar putting a sheet of it on the "inside", on top of which it is an ultra smooth plastic surface, not ideal for affixing to the shell. Also the base sheet would require an application of paint, and not just any paint [shiny surface again] to enhance the glitter and hide the wood underneath.
While at the art supply store I looked at construction paper and initially felt it was too "weak" for the purpose. But then, this is drum wrap; not anything that will be batted about or abused to any degree, and it will be sitting on the shell nice and tight, so really only the outside has to be strong enough to withstand the odd bump without tearing. The great bonus of construction paper is that it comes in many colours, negating the need for any paint.
I purchased two sheets of construction paper, one an off-white and the other a light blue/gray putty colour, as in the base for Ludwig silver sparkle. Now Ludwig used mostly hex glitter, cut from sheets. If you look real close you'll see there is a lot of the base colour showing. Anyway this is real German Glass Glitter, so the base colour won't be as important but still a good idea I think.
So I have simplified the process to this - acrylic gloss gel on the paper; apply glitter; wipe off any loose glitter after drying; nice thick layer of gel on the top sheet Dura Lar; apply top sheet to glitter encrusted paper; squeegy out any air bubbles; let dry and glue to shell. You could also just tape the seams, but I like to hear that woody sound all around the shell when I knock on it.
Pics show glitter in a jar. Watch this space....:)
Mitch