Did you know that hairspray can be a really great tool for sandcarving?! Hairspray?!....I mean who knew!
Hairspray can be applied to the surface of what ever type of substrate you intend to sandcarve, also known as pre-treating. In terms of pre-treating stone, the purpose of the hairspray is to act as a barrier so that when you apply glue, or blastable adhesive, the glue won't absorb into the porous medium.
Another great reason for adding hairspray as an accessory to your sandcarving workshop is mask application. A quick spray of unscented hairspray to your substrate will help adhere photoresist masks because it has a slight glue tack to it. The key is to let the hairspray dry before you apply the mask, but the drying process is very quick, about 1-2 minutes depending on the substrate material.
If you're performing a color-filling technique post-sandcarve, hairspray can also be used as a barrier to prevent paint bleeding before you remove the mask, however, a matte clear coat can easily work better for the application. The reason IKONICS suggests a clear coat vs. hairspray for this method is because you don't want an extra tack after color-filling that could result in your paint sticking to the mask and the walls of the carved areas. This could potentially lead to paint peeling out of carved areas.
IKONICS Imaging suggests using unscented hairspray, preferably AquaNet. Plus, you'll have this amazing spray on hand if you're feeling 80's nostalgia or need a quick hair fix.