Make some abs sluge to do the filling and scuff up plastic and drill some holes for the glass.
If u wanna fill cubby Just use some t-shirt material and glass add like 2 layers of mat and your good use filler and sand smooth.
Or if move ac or what ever take some abs plasic put it in a glass jar and put accetone or mineral spirts in it it will eventually turn the plastic gooey. Then take it out use a spreader and fill it will harden like new plasic once it dries.
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