Create an equation for multiplying weight of part with QTY. (you can create variable for QTY also so that just need to be updated only at one place) and use that.
Here is a similar post: display-mass-in-dual-units
Thanks for that, this should work ok.
You get correct answer
Yes I know I could add an equation in a BOM, unfortunately where I need the total is not in a BOM it is in a drawing title border.
Thanks for taking the time to reply.