Cube damage only by certain weapons?

So i want to make my cubes(blocks of all tier) not take damage by weapons and only by siege equipment(treb and ballista) I have went into the blueprints.default in the mods folder and changed all the values of damagebyweapon to false and then saved it but then when i restart the server it all reverts back? and you can damage the blocks with weapons. Also the wooden club does 1000 damage to a stone block.

 

You shouldn't change anything in the default files.
Copy the blueprint file and remove the .default from the name.
You can edit the data that is in there.
Example:

 

Thaks alot bro.