Part Suggestion : Mass simulator (Boilerplate)

[Fatboymicro]

When you build and test stages, especially first stage, you need some part that have mass and volume and do not have other properties (i.e. fuel, elrctric charge etc) 

right now it is very difficult job to construct "mass simulator" from fuel tanks or engine or smth else.
It would be cool to have different size (mass) dummy steel discs for this purpose.

 

Thnx.

[dr.phees]

Absolutely necessary. And there is no reason why tanks should not have a toggle button to switch between various fuel setups and a "mass simulator" option (probably using hot liquid lead or quicksilver, as far as I understand Kerbals)