Hair spray...It's shellac for your head.

Shellac is a bodily excretion from the asian lac beetle. [:'(]

Shellac is fairly brittle and probably will crack over time. It probably won't fill in the grain of the fabric since it's so lite. It's not film forming either.

In addition, it's water soluble and becomes sticky when wet. It's ok as a fixant on drawings or as a lite sanding sealer. Personally, I'd use real shellac for a sealer, not hair spray.

You should seal the fabric with nitrate dope. It's light weight, flexible, and will fill in the grain of the fabric.