Did you know that your Athame does not have to be metal? When I was searching the internet for Athame ideas, I saw several for sale that were made entirely of wood. I saw another website where the blade was made from slate. Check out the website for ideas; http://www.spiritofold.co.uk/general_shop/athames.htm
As far as the hunting knife goes, I understand from research that if a blade has been used to cut meat or human flesh(as in stabbing), not to use it. You stated it has not been used so, that would be OK. Also, I understand, it is better to craft your own. As a metal blade would be difficult, that is why, some witches have one that is made of wood. You see, the Athame is not for cutting material objects as it is really meant only to cut through spirit and astral realms.
I bought a plain wood handled metal blade Athame, and as I could not make tiny perfect symbols as I seen in a book to decorate the Athame's handle, I copied the symbols and reduced them to a comparable size for the wooden handle. I glued them then, I polyurethaned them so they would not get dirty from use. I suppose I could have used a wood-burner to etch in the symbols but, that would have been extremely difficult.
As far as blessing or, consecrating the Athame as well as all your other magickal tools. There are many. Try a search here press the spells button then enter bless athame. If you want more information as I did, google consecrating the athame that will cough up several methods.