Awesome!! How long did this take you? How thick should the Perspex be for highest performance? Is it worth going any thicker than your 5mm? How much expansion did you allow for with the expansion and contraction you mentioned with the Perspex? 2mm all around?
A few additional notes. Nails would be neater than screws, but i want to be able to get in-between the panels if i need to. Particularly if this idea failed or to refill silica at some point. Also perspex isn't critical in the design, glass would work well too. However, there is better thermal performance from perspex, especially thick perspex. 🙂