[Crex]

You can also use a section of black pipe as an internal "oven". It will block the direct heat from torch and even out the temp nicely preventing the "hot-spot" issues in a lot of forges. Just give it time to come up to even heat before trying it out.
Or....take a section of medium hard fire brick, scoop out to look like a canoe with no ends and use it as you would the pipe for a even heat tunnel.
Both are simple tricks.

On that trashcan forge......he's burning off zinc oxide around the portal....highly toxic to humans.
Not very smart, has been credited with killing a lot of people especially in the WWI trenches in Europe.
Basic ingredient for simple mustard gas.
Also reports of several modern day knifemakers suffering from similar illness when using galvanized metals during forging process.