I want to start this out with I know I'm probably over killing this project from the begin but, I'm trying to make tray organizers for my toolbox. So the project is I wanted to make a vacuum form of both the tools laid out how i plan to have them in the drawer, then vacuum form the inside of my drawer hot glue the two forms together then fill them with some type of medium ( e.i. foam or gel). I'm having problems finding said medium that will not cost a small fortune and is not extremely heavy. I have tried foam for insulation and the problem that i have ran into is it doesn't want to harden proper inside the form. which I this is because there is a lack of air for it to expand any suggestion or has someone made something similar that I could try to make.