You can easily set Default cart weight to 0.00 or to a specific value when scale is disabled. You can do this from Settings Tab using the steps outlined below.
1. Click the Settings Tab from navigation menu on Homepage, then click on Users -> Scale from side bar. It will open scale settings page.
2. In order to disable scale and set weight to specific value , click on Disable scale radio button.
3. Scale Weight can be set to
Weight From Cart: Default cart weight will get applied while shipping
0.00: Weight will set to 0 while shipping
Other: if the option is selected it will show text box to set weight specific value while shipping
4. Click on Save button at the bottom, it will disable scale for you as weight will get applied as per set while shipping.