OK...so now I have built a containment area for my furnace but I need to cover the top, and the top needs to be movable and maybe reconfigurable so I can simply drop in cans into the crucible within the furnace. In trublue Mark fashion I will over engineer and over build the top. I started out with some 2 in (or so) angle iron and I cut, clamped and welded a 20 in square frame. Into this angle iron frame I laid expanded steel mesh...actually I had to use two pieces as they didn't quite fit the frame. The big 1/2 inch rebar grid I made thinking I would suspend the angle iron frame (loaded with 1 inch firebrick) from it and then with a simple pulley block system I could counterweight the top and have a one hand operated furnace lid.
Of course if had measured the firebricks before I built the frame I could have made sure that they would fit properly into the channel. So instead I had to play the puzzle game positioning and stacking the fire brick to create a covering with an access hole to ad material to the crucibles.
Well by this point I had abandoned the heavy rebar support grid and have welded a couple pieces of #2 jack chain to the corners of my angle iron furnace top...these I bolt to another chain running through a shackle and then to the opposite corner, a 1/4x20 bolts with fender washers joins the two chains. The shackle on top is attached to some witre rope running over two steel pulleys and counter weighted with two steel plates from my son's old weight bench. Glad I didn't throw them away!!
Here is another view of the front of the furnace showing how I had planned the angle iron/fire brick to cover the top of the furnace. Even with this much weight on the frame I was able to counter weight it enough that it is a simple one handed operation to raise the top. As you're looking at other sites you will see this isn't how to open the furnace efficiently...most folks use a cam style foot or hand operated lifting mechanism to lift the lid which is then swung out of the way for working.
