The trailer I designed on 2d autocad, basically I measured the length of the tank and made the trailer to suit. The tank weighs around 8kg, so the trailer needed to be fairly strong.
My idea was to make to spines the full length of the trailer and bolt it altogether with cross members and outriggers.
I made the spines from 4 pieces of 1mm sheet steel and sandwiched perspex between each pair.
After making wooden templates and cutting out the steel, this is what I ended up with.
The next fun part was cutting them out.