My husband is always trying to help me when I get involved with things. Like when I dedcided I wanted a fish tank I drew up a design and he built me a very nice stand. Now that I have a guinea pig he wants to build me a cage. I told him about this site. He really liked the cage designs but wants to use plexi glass in place of the grids. I told him I didn't think it would allow for enough air flow. Am I right or is it safe to us plexi glass? I suggested that he could make the coroplast part out of the plexi glass with 5 or 6 inch walls. This I think would be a safe way to use plexi glass.