Keeping weight under 1.5Kg is going to be a lot harder than I thought. The mass calculations in the OnShape CAD very quickly highlighted that the initial design was not viable without some radical rework. So bulk heads will have to be lightened. I am still working on the idea of using those 12.7mm thick Bonzer Chopping Boards for these components, as they are such good value; but I may have to go thinner.

Bulkhead.png
The idea remains to build a sub-frame to bolt armour on to the outside and to fix the internal parts to. M5 counter sunk bolts should suffice to hold the structure together. Well back to the CAD for me...