what kind of materials would I need for a cheap DIY caldera with inferno insert for wood burning

Others have more metallurgical experience than I, but I can't imagine aluminum failing so quickly that you can't test it out. Sure long term use it'll get burned through but for a half dozen tests you should be fine.

Also if your systems has a meltdown…well then you've probably got a decent design that will burn plenty hot for any of your needs ;)

The temperature that you get inside a wood burner depends a lot on the type of wood, the dryness of the wood, and how finely divided it is. If you get just the right amount of air underneath, it can get very hot.

My results were always limited when I had too many pine needles or if the wood was damp. Shoot for wood pieces no larger in diameter than a pencil.

The advantage of working with steel or aluminum first is that you can get your design dimensions worked out before you go to titanium. The disadvantage is that it is still a lot of work, and if your metal gets deformed within one or two burns, all of your work goes up in smoke before it can be thoroughly tested.

–B.G.–

Before I designed my FireFly stove, when playing around with my ti tri CC, I made an aluminum insert out of a "disposable" aluminum roasting pan (heavy aluminum foil, essentially), lighter than aluminum flashing for sure. It has a 3" square piece of carpenter cloth as a central shelf and the aluminum makes a very shallow inverted cone to come up close to the inside of a ti-tri CC. It essentially serves as a fire basket inside the cone to concentrate the burning twigs and give the fire more airflow from underneath the twigs. I used this at least a dozen times and it held up OK. I think this works because the aluminum is essentially under and/or to the side of the hottest part of the fire and is not subjected to melting temperatures. It was also easy to fold up and store under my pot in it's stow bag.