Sometimes we tend to complicate things far more than they need to be. By taking a look at the elaborate items in use and simplifying the method by which they are made I think that a whole lot can be done with grassroots methods.
Finnr
Files are cheap enough that after A couple cleanings when the are in fact dull, they become stock. Less effort to pick up a new one than fiddle around trying to make a dull fine less dull. Wore out is wore out!
Finnr
Here is a real bad shot of a rose I did for an old High School friend. I will try for a better picture tomorrow when I have daylight to work with.
Finnr
Covforge is exactly right. I used to puddle lead on auto bodies when they weren't made out of used beer cans. The same body files I used for that are now being sold by high dollar woodworking suppliers for shaping wood.
Finnr
Last soda can I welded was long enough ago that it had the pull off tab. It can be done, expect more failures that success till you get it all figured out. That was with an O/A rig.
Finnr
I have never seen a different type other then the horribly expensive copper wash boilers, but a piece of light sheetmetal from your local steel yard is cheap and one less thing to worry about.
Finnr
Give some thought to pulling out the cement unless it's refractory and putting in a layer of clay. Cement is going to spall in no time when you subject it to heat. One other worri I have is the wash tub. Zinc fumes are just plain un healthy. Other than that. Looks like you are up and running!
Finnr