The Rocket Forge

Hi to all,

Blacksmithing has been a persistent, albiet underindulged hobby for me, but it seems as though there is enough need for handcrafted iron that it might be worth an experiment to try to make a little side out of it.
I have wood aplenty, and access to red or softer oaks with petty good btu value.  My question is how can I optimize the rocket stove idea into a super hot rocket forge for plasticising metal and soft metal casting?
Any help most appreciated.

To date I was considering a fire brick liner, a blower, a layer of insulating sand topped by more stones and Earth.

Many thanks...M

Have you seen this plan for a rocket canner fryer and forge. https://permies.com/t/rocket-canner-fryer-forge

If I were to attempt this I would create an aperature in the riser whereby one could insert the metal to be worked directly in the upward flowing combustion path.  That should be about the hottest part of the burn.  Now the trick here is determining just how long you want the heat.  J or L tube design, or batch box?

Hi Thomas,

Cant really visualize what you are saying. Here is a rough schematic, if you have (or anyone else on the board) has  paintbox and wants to tweak it, I wouldnt mind.  Its still evolving. Many thanks.

Bought a 22 lb anvil to start and a kit to assemble some tongs. Got three 2 lb sledges on sale for less than $8.00 each and that gives me a total of 6 faces when I grind them.

What you have here is what's known as an "L" Tube configuration.  Cleaning chute is probably overkill.  You don't want to allow too much air into the combustion chamber.  What's more important is you allow the fire to go up and out of that forge zone.  You don't want to slow it down.  I can see a five minute riser coming into play here, terminating just before the forge zone.  Trick is to bleed off excess heat before exiting the chimney.  Is this going to be an outdoors thing?  Or can we work on a means of capturing excess heat for warming the space?

Its going to be outdoors.  I have lots of trees so I was actually thinking of attaching a bellows to a limb if I needed extra air.

I still dont understand the idea of the riser, sorry.  So narrow or reduce the air intake (or make it adjustable) and elongate the horizontal part of the tube?

The oven itself i thought of as a kind of Pizza oven style, or pizza box style I should say, with a low maybe 4 inch ceiling at the most.  So what is the purpose of the riser?

Thanks for the assist.

M

Rocket Forge 2.0

The "Riser" is the path of the combustion gases that move vertically.  It creates the draw through the firebox (combustion chamber).  By opening that up, the fire is less restricted and can reach maximum temperature.  Since your build will be outside, then you could have a shroud over the forge area, like a pizza oven, just as long as it's open enough to let the exhaust gases out in a safe direction away from the user.  I think what you have sketched up is a very good start.  Have a look around at the various building and insulating materials for refractory work like this.  If you can imagine it, you can build it.  Looking forward to seeing this happen.  One more thing I might add is to make your feed tube a bit shorter to make it easier to start.  Ideally the riser should be taller than the feed tube is long.

Yes I can see it. I thank you for all of that. I will make it happen and post pics.  Much appreciated. Very excited with my toys and the opportunity to learn skills. M

Hey Michael;
Its not a rocket stove,  but check out this homemade wood stove forge.
Its a great video all the way, but part way in he melts down his own zinc and copper to make brass slabs.
Very cool.
https://permies.com/t/164581/Hand-Oak-table

Something for Michael to consider is the possibility of having a fuel bin with a lid that, once he got his fire going,  he could pressurize with a blower of some kind and supercharge the fire coming from his riser.  Of course that would take us out of the realm of the naturally aspirated fire, but if the electricity is available, why not pump it up when the heat is needed and turn the blower off when it is not?

Thanks Thomas I had thought of that in terms of a dampener on the top, which could be constricted to slow burning and pulled back again to let it rip. Also some projects call for lower or higher temperatures depending, annealing, spring and tool making etc, require some temperature control, so there should be a number of hot spots for different for different things......Traditional blacksmiths forge usually have some sort of forced air source, Ive seen a couple of rocket stoves that were used for backyard cooking and was really impressed--I know where it got its name "rocket" looking at the flames eminating.  I may not need any forced air. But we will see. Maybe I'll want to melt iron one day?

Thanks great thought.