The use of service vs consumable depends on whether you want to track an inventory of consumable items or not. If not, use the service item. Otherwise, as suggested, put the items in inventory as a Sales Inventory item in a class ID of Consumable. Then when you pull them out of inventory, do an inventory adjustment transaction and change the account number to expense them to the correct departmental account. If you upgrade to V2013, the Reason Codes can be setup so users do not have to change account numbers but can select reason codes such as "Issue to Shipping" and the correct expense account will be hit.
This feature of 2013 is discussed on our video on Version 2013. Visit our website to view it.