When you create or modify a Masterwork Weapon, you can add the Explode property to any weapon that deals Fire damage. This property uses the following rules.
Melee Explosions
You can add the Explode property to a Melee weapon. When you use this property with a Melee weapon, the explosion is centered on a point within your reach, and you take no damage from the explosion.
Saving Throws
You can use the following calculation for the save DC of your Explode property: 8 plus your Intelligence modifier and Proficiency Bonus.