Joining Meshes

I have recently started Blender and have encountered some problems after joining my mesh:

I have built the model in 3 pieces as shown in the first picture,
once I had finished sculpting it I went on to join the blade and the separating peice between the blade and the handle, everytime I join them the blade sort of pushes into itself.I have also put a picture of this too. How do you get rid of this?

im fairly sertain that is due to a modifier, cause when you join modifiers, the object will keep the modifier of the object that was last selected before joining the meshes together.

Oh, ok thanks, i had the mirror on and hadnt applied it