what adhesive are you all using to get the styrofoam to glue together, i have liquid nails interior projects and it is not holding the pieces together after 12-14 hours the pieces just pull apart and the glue seems to still be wet. The tube i got is brown and red in color, am i using the wrong stuff or doing something wrong? any advice would be great, and for sealer can i use modge podge or is there anything better for around the same price? thanks guys