Justin Popa

muds sketches of the current rocket engine and how we might use it as a forge. using either the hot gasses or the coals themselves.

Hey everyone! im super excited to do some metal working with yall this summer and it seems there is a lot of interest in a rocket forge experiment so lets get it started!

tickets to the PTJ can be found here! --> https://wheaton-labs.com/permaculture-tech/?f=625

The goal of this project is to build a forge and bellows, and to experiment with a rocket forge.  students will learn the basics of forge design, hammer work, and heat treatment of tools.  experiments will be conducted to incorporate rocket design features (clean burn, self feeding, natural draft) into a functional forge.  the Lab will be left with a functional forge that will burn wood, charcoal, or coal and a bellows to provide the air.  

phase 1. Building the forge and bellows:
we will build a "regular" forge.  using simple materials from the site we will construct a forge that anyone can replicate at home. an ancient design that still sees use by talented metal workers to this day. Uncle Mud wants to call it a Dirt Forge. people on the smithing forum "iforgeiron" sometimes call it a JABOD (just a box of dirt) (pics to come)

a set of hand operated bellows will be built to provide air for the forge. (pics to come)  the forge can be run with a thrifted hairdryer as the air supply if people are feeling anxious to get a fire going before the bellows are done.

the dirt forge and bellows will work as our control so we have something to compare our rocket experiments to.

phase 2. rocket experiments:
broadly speaking there are two approaches here.
1. direct the hot exhaust gases from a rocket engine into a insulated work chamber where the iron is heated. this is most similar to how modern propane forges function and is how the current rocket forge functions.

2. use the strong draft of the rocket riser to pull air thru the fuel (wood, charcoal) and bury the iron to be worked directly in the coals. this is most similar to how solid fuel forges work and takes advantage of the greater heat transfer between the coals and the metal, rather than just using the hot gasses.


we will have a beautiful 8in rocket engine to play with for these experiments, as well as the basic materials to cobble together a simpler rocket core

note: throughout phases 1 and 2 we will be using both forges to construct blacksmith tools that will stay at the lab  

phase 3. goofing around:
building a small retort for making charcoal that can be placed on top of the rocket riser. wood gas can be sent back into the system.
make the bellows pedal powered!
find other projects around the site that could use some fancy iron work

did a bit of poking around the forums and gathered up some good information about the work thats already been done:

the rocket kiln project last year produced some great data here: https://permies.com/wiki/184037/Inch-Portable-Modular-Rocket-Engine

my notes from this thread:
8 in engine kiln in low position 2077 bottom 1945 top. 2 hours (pass thru)
6 in engine kiln on top of riser 2296 bottom 2259 top. 5 hours (pass thru)
Pauls 2088 top 1945 bottom 5 hours (captive design)
these numbers represent the "heat work" done inside the kiln.  for hobby smithing work these temps are fine, the question is can we get the steel to these temps in a couple minutes rather than a couple hours.

this thread has a lot of good ideas too. dealing with forge design (for smithing) and furnace design (for melting metals): https://permies.com/t/166851/rocket-forge-steel-insertion-crucible

my notes from this thread:
A hole or door in the vertical riser in the sweet spot. (this is the current version of the rocket forge)
The hole could have a foot activated door. (not an uncommon design on modern propane forges)
Built in retort after the forge area for making charcoal, wood gas to be sent back down to the feed tube. (there seems to be interest from others here. might as well utilize some of that wasted heat)
Multiple feed tubes with risers spiraling around a central crucible. (love the go big or go home energy)
Paul says no shop vac for the rocket forge/ furnace experiment. (i agree. if we are gunna use a forced air draft its not really a "rocket" any more)
Paul thinks crucible access should be from side. (meh. top access for loading materials during firing is nice)
Insulated chimney above work area to increase draw. hopefully will help the forge draw better even if the forge doors are opened

Bellows talk!

there are lots of ways to push air.

modern smiths tend to use what is often called a blower. a fan or impeller that is turned by a motor or hand crank to push air into the fire. the air flow rate is easily adjustable and they dont take up a lot of space. we are not going to make a blower but we can thrift a hairdryer or old furnace fan to work as one in a pinch.

before the blower was the bellows and they come in lots of designs.
to keep things simple id like to make a pair of single lung bellows. they should be easy to make, easy to transport and store, and give us the ability to adjust our air flow rate.


if we build two bellows, each one 2-3 feet long and 1-2 feet wide, we can keep a steady and adjustable supply of air moving into the forge. they can be operated by one person while another person uses the forge or we can rig them to a frame and have them operated with a single lever.

tools needed to build the bellows:
saw, drill, rasps, scissors/ razor

materials needed:
wood, nails/tacks/screws, glue, leather or similar "skin", some bits of pipe

are these tools and materials available at the lab? specifically im concerned about the material for the skin of the bellows. soft leather is the best but a tight canvas might do. if push comes to shove im sure a bit of old vinyl billboard will work too.

thoughts?

things are coming together!

Beau. a shade sail sounds great. we can rig up something extra if its still too bright but i woulndt worry about it yet.
the forge cares not where the air flows from, only that it flows! a hairdryer or a proper bellows will be interchangable.

Thomas! thanks for the pics, my dude!  it looks like yall have more than enough steel to play with.  im sure we can find a way to hook a bike up to the bellows as well, in fact, i insist.  people have always been looking for a way to not have to pump the bellows. in big shops they were often powered by a water wheel, but ive seen at least one 18th century image of a nail making shop where the bellows is run by dogs walking on a giant hamster wheel!

Also also!
early last week i had a nice long chat with Uncle Mud about this project and the work thats already been done on rocket forge designs.  we talked about what people have already tried and about some fun discoveries they made.  he said the realy nice 8in rocket engine they made last year (the year before?) will be available for this project! which will be a huge help in the rocket experiment phase.

at this point the main goal for the project is well established. ill change the top post on this page to reflect the primary goal of "build a functional forge, bellows, and tool set" ill start sharing my thoughts on the secondary "experimental phase" as soon as i can get some sketches down on paper.  

thanks for the feedback everyone!

Beau: a tent is fine as a building and experimenting space. whats most important is some deep shade so that the color of the hot iron can be read easily and ventilation so people arent sucking in smoke.  ive done my fair share of shade tree blacksmithing and its nice to be out in the breeze.  on the other hand its much more efficient to have a bench and anvil and forge all mounted firmly to level ground inside a proper shop.  working inside would mean needing to install some kind of flue for the forge or furnace. even rockets produce gases we dont want in enclosed spaces.  i think the easiest would be a covered outside space to build and play and experiment, and we can work on creating a permanent inside shop space as time and interest allow.

as for material volumes. "normal" forges and furnaces are pretty small and simple so the building materials will be used mostly for the rocket parts of the system. enough junk to cobble together 1 or 2 rocket engines should be plenty to play with  

a final note on air supply.  its already been decided that the rocket forge and rocket furnace experiments will not include any forced air (shop vac, ect). i agree. if youre gunna push the air manually, it isnt really a rocket anymore.  however! for the initial build of the "normal" forge, some kind of air supply is needed.  old hairdryers work great and are easy to thrift. shop vacs work ok but are loud and tend to push too much air unless you run them thru a rheostat to adjust the amperage. and of course we can build some kind of manually operated bellows if people wanna go oldschool.  there are tons of well tested designs for hand pump bellows and i can see them being useful around the labs for future experiments too.  any thoughts on this?  

can anyone tell me about the current metal working space at the Labs?

part of this project will be building a simple forge and experimenting with a rocket forge design. along with that there are a lot of blacksmith tools that we can make once we have a working forge:
tongs for holding the hot metal
chisels for cutting
punches for making holes
drifts for sizing and shaping holes
bending forks and wrenches for bending and twisting
rakes and washers for tending the fire

id love to guide people thru making any and all of these tools. it would be a great way to learn basic hammer work, heat treating, material selection, and finishing.

however there are a few things that would be really nice to have on hand at the start:
a designated covered work area.
an anvil or other large block of steel
a (heavy) bench with a (heavy) vice
electrical access would be cool but not required

to make any of this happen we need materials. no matter what gets built we will need:
earth/ cob
firebrick
rockwool
satanite or other refractory lining
lumber
scrap metal (bar stock, old tools, sheet metal, barrels, buckets, ect.)

also:
Monica, no current plans to make this thing produce electricity but that sure would be sweet

hey all!

Ive been doing some reading and learning about old forge and furnace design and thought id share some really neat examples of human ingenuity in the world of metal working.

First I figured there must be an example of a furnace or forge that uses a natural draft like a rocket, my brother pointed me towards a Reverberatory Furnace used for Puddling Wrought Iron

https://en.wikipedia.org/wiki/Reverberatory_furnace


these furnaces were designed to refine pig iron into more malleable wrought iron but were also used in melting metals for casting. the wiki articles are def worth a read if you like metallurgy or historic technologies.  tell me that thing doesnt look like a rocket!    

i havent found a historical example yet of a forge powered by a natural draft but some of the same principles used in the Reverbatory furnace could be used with a rocket forge.  before electrical pumps and blowers could be used to push air into forges and furnaces large bellows were used. bellows for small forges were hand powered but for large shops they were almost always powered by a water wheel. here is an amazing video of a shop being run with tech that basically didnt change for 100s of years!

https://video.xx.fbcdn.net/v/t42.1790-2/10000000_618012310015050_3883594604958467264_n.mp4?_nc_cat=110&ccb=1-7&_nc_sid=985c63&efg=eyJ2ZW5jb2RlX3RhZyI6InN2ZV9zZCJ9&_nc_ohc=VAdh1sZfMo8AX_aQSjk&_nc_rml=0&_nc_ht=video.fyip1-1.fna&oh=00_AfDfOtXrUohSjMtiq6eIwM8GGrZGIfybNPHEh8IXsnsQeA&oe=645F1E3B

and as a final thing to think about i present to you the Trompe!  an amazing way to turn falling water into compressed air. not a rocket at all but a really cool way to push air without electricity or a ton of labor pumping a bellows.  is there any falling water at Wheaton Labs we can play with?

https://en.wikipedia.org/wiki/Trompe

Thanks for the feed back everyone!

Jules: thanks! here are some of my notes after listening:

2200 gases/ 2000 cones is good for hobby work. Like pottery, we are interested in the temp of the wares inside the forge/ furnace, not just the exhaust temps. The highest temps needed for forging operations like welding reach up to 2400

paul: lots of yellow bricks

Lisa notes the difference between reducing and oxidizing from a potters perspective as the difference between smoke and no smoke. In blacksmithing a reducing or neutral flame is usually desired. Meaning no excess unburnt oxygen should be present where the work is done. The type of atmosphere (reducing, neutral, or oxidizing) desired for foundry work depends on the material being cast and the operation being done. Fuel to oxygen mixture can be regulated by a choke at the inlet (feed tube) and/or outlet (riser).

Lisa notes glazed wares on the bottom of the riser were in a reducing atmosphere, in this instance, the presence of unburnt fuel

Mud : 4 in of insulation, front and back clean outs, portable, modular, high performance j tube $1000

Lisa: high fire 2350 degrees in 5 hours, 3 ½ arm loads of wood

Mud: sweet spot somewhere in middle of riser  

Coydon: thanks! Id one day love to experiment with different wood types and their effects as a forge fuel but for now with so many other things to experiment with sticking with the mixed conifers is fine. one less variable to mess with.

Kenneth: Yes i love the idea! and since it would be using the waste heat after the forge or furnace, it could be built separately and plugged in as needed without disrupting the main system.  i didnt mean to pass this off as my own, i just compiled what i felt was the highlights of last years thread.

William: as far as im concerned a regular ol solid fuel forge is hard to beat, but the whole point of this project is to experiment with rocket stuff so experiment we shall!  the rockets ability to draw gasses without additional forced air is specifically what id like to tap into somehow. ive got some ideas brewing.

Hey everyone! im super excited to do some metal working with yall this summer and it seems there is a lot of interest in a rocket forge experiment so lets get it started!

tickets to the PTJ can be found here! --> https://wheaton-labs.com/permaculture-tech/?f=625

The goal of this project is to build a forge and bellows, and to experiment with a rocket forge.  students will learn the basics of forge design, hammer work, and heat treatment of tools.  experiments will be conducted to incorporate rocket design features (clean burn, self feeding, natural draft) into a functional forge.  the Lab will be left with a functional forge that will burn wood, charcoal, or coal and a bellows to provide the air.  

phase 1. Building the forge and bellows:
we will build a "regular" forge.  using simple materials from the site we will construct a forge that anyone can replicate at home. an ancient design that still sees use by talented metal workers to this day. Uncle Mud wants to call it a Dirt Forge. people on the smithing forum "iforgeiron" sometimes call it a JABOD (just a box of dirt) (pics to come)

a set of hand operated bellows will be built to provide air for the forge. (pics to come)  the forge can be run with a thrifted hairdryer as the air supply if people are feeling anxious to get a fire going before the bellows are done.

the dirt forge and bellows will work as our control so we have something to compare our rocket experiments to.

phase 2. rocket experiments:
broadly speaking there are two approaches here.
1. direct the hot exhaust gases from a rocket engine into a insulated work chamber where the iron is heated. this is most similar to how modern propane forges function and is how the current rocket forge functions.

2. use the strong draft of the rocket riser to pull air thru the fuel (wood, charcoal) and bury the iron to be worked directly in the coals. this is most similar to how solid fuel forges work and takes advantage of the greater heat transfer between the coals and the metal, rather than just using the hot gasses.


we will have a beautiful 8in rocket engine to play with for these experiments, as well as the basic materials to cobble together a simpler rocket core

note: throughout phases 1 and 2 we will be using both forges to construct blacksmith tools that will stay at the lab  

phase 3. goofing around:
building a small retort for making charcoal that can be placed on top of the rocket riser. wood gas can be sent back into the system.
make the bellows pedal powered!
find other projects around the site that could use some fancy iron work

did a bit of poking around the forums and gathered up some good information about the work thats already been done:

the rocket kiln project last year produced some great data here: https://permies.com/wiki/184037/Inch-Portable-Modular-Rocket-Engine

my notes from this thread:
8 in engine kiln in low position 2077 bottom 1945 top. 2 hours (pass thru)
6 in engine kiln on top of riser 2296 bottom 2259 top. 5 hours (pass thru)
Pauls 2088 top 1945 bottom 5 hours (captive design)
these numbers represent the "heat work" done inside the kiln.  for hobby smithing work these temps are fine, the question is can we get the steel to these temps in a couple minutes rather than a couple hours.

this thread has a lot of good ideas too. dealing with forge design (for smithing) and furnace design (for melting metals): https://permies.com/t/166851/rocket-forge-steel-insertion-crucible

my notes from this thread:
A hole or door in the vertical riser in the sweet spot. (this is the current version of the rocket forge)
The hole could have a foot activated door. (not an uncommon design on modern propane forges)
Built in retort after the forge area for making charcoal, wood gas to be sent back down to the feed tube. (there seems to be interest from others here. might as well utilize some of that wasted heat)
Multiple feed tubes with risers spiraling around a central crucible. (love the go big or go home energy)
Paul says no shop vac for the rocket forge/ furnace experiment. (i agree. if we are gunna use a forced air draft its not really a "rocket" any more)
Paul thinks crucible access should be from side. (meh. top access for loading materials during firing is nice)
Insulated chimney above work area to increase draw. hopefully will help the forge draw better even if the forge doors are opened