Step 4: Step 2: Reinforcement and sealing

Picture of Step 2: Reinforcement and sealing
I glued on the aluminium L brackets to provide some additional strength to the structure, and sealed the inside edges with silicone sealant.
Pro tip: if you cover your fingers in washing detergent, the sealant will stick to the Perspex but not your fingers! Otherwise it’s very difficult and messy.
*Ignore the silicone around the top of the apparatus in the last photo – that shouldn’t be there