This pattern is from Stan of Sizzling Solar Systems, his email and mobile are on the pattern if you have any technical questions.
Stan said an optional extra is a computer fan connected to a small solar cell which when positioned at the air outlet will draw the warm air through faster thereby hastening the drying process.
I haven't added either the optional reflector or fan and mine works well.
I didn't have any of the squat boxes at the time so used the standard broccoli boxes, dumpster diving outside the local fruit and veg provided them.
The standard broccoli box needed 3.5 meters of square dowel for 7 sets of shelf rests.
The plastic coated mesh for the shelves I found the hardest to find, eventually found it in a 5 meter roll at Bunnings for just under $50, only needed about a meter. I'm going to make another dehydrator with the squat boxes I recently found but after that I will have 3 meters of the mesh to spare. If anyone wants to purchase some at $10 per meter just contact me, otherwise I'm sure I'll find a use for it in my new veg garden.
For the thin metal heating element/sheet I used some offcuts of 'small curved' corrugated iron I had lying around, this gave me a greater surface area than a flat sheet.
Painted the metal heating element black with pot belly black paint which doesn't need a primer and can withstand high temperatures.
After the dehydrator was finished I thought I'd paint my boxes to both help preserve the polystyrene and to blend them into the garden. It did neither as I didn't know that aerosol paint was oil based or that oil based paint eats polystyrene. It is now quite pockmarked but still works :) Next time I'll use water based paint.
Trust this helps someone else,