Thanks, I've just tried to calculate the armour values, so I can better predict what a bot would weigh with the components I had in mind for it, but when I did an experiment I found the results were a bit mad: 1 square at minimum pixel height of 10mm plastic is 10.6 kg. 2 squares is 17.3 and 3 squares is 23.9. So that's me stumped. Has anyone ever found a way of calculating armour weight to some degree of accuracy?