/diy/ - Do It Yourself

Nothing but fucking useless replies outside /diy/ so I'm going to try here. I'm building a 4x2x2 reptile enclosure out of HDPE (Starboard specifically and I want to know if 1/4" thickness will be sturdy enough. Basic design, it's a box with 1 open side and a bottom/top horizontal brace on the open side. I just don't want it to bow in the middle. The shop selling it to me says it'll do, he talked me down from 3/4" so I assume he's being helpful to me since he could have just said "sure" and take more of my money. Has anyone worked with HDPE and will 1/4" thickness hold up on a 4x2x2 enclosure?

and for the last fucking time yes I checked fucking dubia and no they won't anything to me