A forge I plan on building when I get home.

I can make tweaks and modifications as needed. This is just a rough concept.

The air supply is going to be a 442 CFM centrifuge fan with a charcoal filter(that's whats on the back of the fan itself) and it has a speed selector switch so it's adjustable. 

It will go from ducting into a pipe that will hopefully be able to be placed at the bottom to supply the forge with the airflow it needs. If I do run the piping down the center like that, holes will be drilled to allow the airflow to go through but I'm not sure how that would effect how it's displaced through the forge itself, or how long the length of the pipe leading to it would effect it as well. I.e. whether or not it would be getting sufficient air supply.

The inside is lined with firebrick(the brown-yellow inside), I'm just not sure what to build the outside or base from for it to be the best or what would be the best for it.

Any suggestions?

First: Can you tell us the fuel you plan to use? Charcoal, bituminous coal, anthracite, breeze, industrial coke?

Second:  Mock it up as a JABOD and play around with it a while till you figure out if it's what you need or modify it a few times till you like it and then make the fancy version!

I plan on using charcoal most likely. And a JABOD would be good to start and tweak it, I'm just not too sure as to what I want the outer walls and stand to be for the final version. Steel, maybe? Plus how's the design of it look too? Seem practical enough? When I make a final version of the model, I'll be adding the dimensions of it too.

Use the JABOD as a test platform. You can easily change and modify to get the best results for you before you build the next forge.

Don't worry about the final version yet; work on figuring out what style/shape/fuel works best for you and then worry about how to make a more permanent version of it.

All great advice they have given, JABOD let’s you find the shape and size you want before putting money and effort into something permanent. 

One note on that blower, IT IS HUGE. 100cfm is more than enough and will need throttling. Not saying to not use what you have, just saying to be aware of what you are dealing with, variable speed or no.

Have fun!

Steve

Thank you Steve, and I know 400 is a lot but it also won't be right next to it. I'm gonna figure some stuff out for it and do tweaks when I get home.

Instead of the elbow where the air pipe from the fan turns 90 degrees towards the forge, install a tee with some kind of gate on the open end. That will allow you to waste your excess air in a controlled manner.