Continuing the build and again, publishing on FtB first.
The second part of manufacturing my new forge was finishing the mobile base. It was easy – I just filled the newly made wheelbarrow in three steps.
© Charly, all rights reserved. Click for full size.
Firstly I have put a few bad fire clay bricks on the bottom. Their main purpose is to provide ballast and lower the center of gravity in order to stabilize the future forge.
© Charly, all rights reserved. Click for full size.
The rest was filled with pearlite. It weighs nearly nothing but it is an excellent inflammable thermal insulator.
© Charly, all rights reserved. Click for full size.
And finally, I have put thin (ca 2 cm) fire clay bricks on top. I was considering making one big fire clay slab but I think this is a better solution because the heat transfer between separate bricks will be slower than it would be within one big continuous slab. This way the heat loss should be lower. And whenever a fire clay brick cracks so much it becomes unusable, I can replace it anytime and easily.
Thus filled wheelbarrow is sufficiently heavy so I cannot easily knock it over by an accidental bump, but not so heavy so I cannot move it. And the top layer of firebricks makes a large inflammable working space ca 38×100 cm where I can weld, or put my current small gas forge, or build a charcoal fire. And I also can build a new gas forge on top of it – about that next week.
Typically, one builds a forge atop a metal plate lifted off a table with allthread. Of course there is firebrick above the plate. But the air temperature under my forge at full blast (2200F+ interior temperature) is room temperature.
But I’m sure a wheelbarrow full of bricks and pearlite is pretty stable thanks to gravity!
@Marcus, it is very stable. I have decided to go for this construction because I need it to be mobile so I can tuck it away out of the rain and wind when not in use and this was easier to make than trying to weld some mobile table like for a BBQ. Welding some metal mobile table was actually my first plan but I did not have enough suitable material for that. Not to mention that I suck at welding and I could not weld now anyways because I have to do it outdoors and the weather is not good for that kind of work for over a month now.
Mobility is a nice thing to have on something like a heavy forge. When working on large things, you can move the forge close to the work, instead of trying to fit your work into a crowded shop space.