The Arc Furnace Electrode Engineer's Blueprint Item ID 7414:2, has a 6.8% chance of spawning in the Stronghold Library and a .4% chance of spawning in a blacksmith chest, it's a /very/ rare item and cannot be copied to be resold, like the Applied Energistics Presses can. It's the last part needed to create a functioning Arc Furnace, without it, you have a very expensive lawn ornament. Not saying it should be cheap, mind, the Arc Furnace is a powerful item once it's finished. This is on the Infinity Modpack.
