Can I turn this cast iron grill into a usable firepot with possible tuyere?

Question

I have bought a cast iron grill or furnace and saw the top part had a nice shape for a possible firepot. The bodywork under the pan and grill is entirely hollow and looks like a pot. The hollow bodywork could help construct a tuyere inside. For airflow I have created a separate system that outputs an adjustable airflow through a 3.5 inch tube.

I'm wondering how feasible this is in terms of efficiency, as I am worried this will be as effective as a brake drum forge, which I don't find a good choice. The top bowl and grill can also be removed separately. Would it be possible to construct an efficient firepot with this or is it just not the right design or shape? If it's not the right choice, would that mean this is completely unusable as blacksmithing implement?

Answer 1

Will this be mounted inside a larger 'table' made with firebricks, refractory, or something else or do you intend it to be 'free standing' as is? If free standing it should be suitable for light use (demonstrations and such) but I would keep to hand crank blowers as an air source. I knew a smith who used a cast iron frying pan as a demonstration forge (he cut a hole in the bottom for the tuyere) and what you have looks similar in thickness.

It certainly could be used as the basis for a blacksmithing forge and IMHO would be no less efficient than a brake drum.

Answer 2

I would say no, on a few points.

1. the bars in the grill are too far apart .. you will lose all your burning coals once it burns into coke form and starts fragmenting
2. The pot itself is small so has no room for a supply of fresh coal to be raked in to freshen the fire
3. punching holes in cast iron to attach the pipe for the air flow is hard due to its brittle nature.

better to make one centred in a larger tray from heavy sheet

suggestions on this board

Answer 3

Yes, it's nearly ideal for a tuyère. You didn't explain how your forced air will enter. If I may, I suggest a tangential opening as the swirling air flow has many benefits for an even burn and economy of fuel. As has been pointed out a steel or brick pan can easily be added.

Bear in mind that liquid slag will drip straight down from the hottest area directly above the grill. Typically the air intake will be placed to the side to allow this slag to pass into the clean-out trap. Usually closed with a sliding or swinging door. A waste pail, often filled with water is placed below.

The main feature of most good tuyères is a shaker or rocker with a handle extending to wherever your standing edge comes out. You'll need to break slag and clinkers which will build up and block the air flow. That's probably only an issue if you're running it full time. You can scrape it with a poker. Make sure your clean-out is easy to operate while hot. Don't make the catch or hinge too fussy that it will get stuck when hot.

All in all it's built very similar to most of the portable rivet forges I've had, it should last a lifetime and then some.