weight of tray

Size, material, etc etc etc. Too many variables to give even a vague answer. Of course the tray manufacturer would be able to give you an exact answer but I guess that is too obvious. Get the drawing, calculate volume and multiply by density is another way, you could even weigh a section.

The detailed mechanical construction drawings for the column, which will either be dimensioned or scaled, are the starting point.

Thank you very much for your kind attention.. I think ill do the calculation based on your suggestions..