You can use royal icing, which is merringue and powdered sugar. You
should be able to find a recipe for that in any cookbook that has
cakes. Or you can go to your local craft store and buy Wilton
Merringue Powder in the cake decorating dept. The recipe for royal
icing is in the can.
But, if you want clear “cement,” just melt 1 cup sugar in 1/2 cup
water in a skillet over the stove until it turns golden. Then dip
your edges in it and they will stick. You can also use that for
“glass” windows, and chimney smoke. Pour it out onto waxed paper to
the size you want. Good luck.