Introduction: Make a Propane Forge for $50!

Picture of Make a Propane Forge for $50!

If you're tired of using the BBQ as your forge, this project may be just what you're looking for! Using a combination of new and scrap materials, we make a propane forge for $50!

Step 1: Tool and Materials

Tools

(Minimum compliment)

  • Oxy/Acetylene Torch
  • Drill with masonry bit

(Standard compliment)

  • Hacksaw (I used a portaband)
  • Welder (Any would do, even oxy/acetylene, I used a MIG)
  • Drill with Masonry bit
  • Cutting torch (or plasma cutter)
  • Tape measure

Materials

To allow for maximum flexibility and use of available materials, I'll refrain for specifying sizes so you can more readily use the material you have on hand.

  • Firebricks (mine were 1½x5x9½" and I bought 11)
  • Angle Iron to frame the bricks (mine was 1½x2½x¼")
  • Plate steel to form the floor and ceiling (I found a piece the perfect size that had some interesting bends in it)
  • Steel tubing to form the legs (I used 1¼x⅛" square)
  • Propane Weed Burner

Step 2: Frame the Bricks

Picture of Frame the Bricks

Lay out the bricks that will form the floor of your forge and cut the angle iron to frame them in. I cut triangular notches in the appropriate places and bent the corners for a really clean look. The piece I had was only long enough to wrap around three sides so I was not able to do it with a single piece. On the bright side, if all you had were short scraps, you could just cut mitered corners and build it like a picture frame.

I wanted to make sure a nice floor was in place to support the brick, so I cut a piece of plate steel and welded it in to fill the void in the middle of the angle iron frame.

Step 3: Add Legs

Picture of Add Legs

You can actually use whatever you want for legs. I used 1¼"x⅛" square tubing, but if all you have is angle iron, that will work too. You may want to add some cross bracing for stability though. I had two seven foot pieces of the square tubing so I cut four 40" legs. To give it some style and stability, I cut them at a 10° angle with a 10° miter. This resulted in an angle that, if aligned properly, would result in all four legs slanting away from the center of the floor. Miraculously, when I sat it on the floor it did not rock. Usually, I have to do some grinding to get things level.

Step 4: Put a Hole in the Floor

Picture of Put a Hole in the Floor

Determine where you want your burner inside the box. Many people want the burner in the top pointing down. Some people also like more than one burner. I'm on a budget and I like my stuff to look cool, so I went with one burner at the back pointing up out of the floor.

Set your brick into the floor and draw a circle on it where you want the burner to come through. Using a masonry bit, drill a series of holes around the perimeter of the burner hole. Drill them all part way through at first to establish the location, then come back and using a rocking motion, both punch through the brick and connect the holes to each other. If you're careful and patient, you'll be able to get a relatively clean hole in the brick.

Mark the location of the hole on the steel floor and burn it out with a cutting torch or plasma cutter,

Step 5: Frame Your Walls

Picture of Frame Your Walls

This forge is fairly small with interior dimensions of only 5x7x9½." Plenty large enough my projects though. Because of the size, the walls of this one are formed with only three bricks laid on their sides and all I had to do was weld angle iron uprights in the corners to secure them in place.

Step 6: Install the Roof and the Burner

Picture of Install the Roof and the Burner

Two more firebricks as the roof complete the build and I found this cool bent shape that just happened to be the right size at the steel yard to cap it off and hold the roof bricks in place. I retrospect, I shouldn't have welded it on. That way should any of the bricks break, I can easily replace them. Live and learn.

I installed the burner by welding a piece of ½" square tubing between the two back legs and wiring the burner handle to it with the Clampmaker®!

Use another firebrick as a front door to keep the heat in, and to keep from singeing your eyebrows when you throw it into turbo mode.

All the steel I got for this project were remnants at the steel yard and only cost me $10 for all of it. Be frugal. Shop around. Metal recyclers are even cheaper usually, but I wanted all new materials for this project so it would be nice and pretty. I spent $20 on firebrick and $20 for the weed burner for a total cost of $50.

Step 7: Watch the Video!

Comments

SANDBOX1 (author)2017-11-26

GREAT JOB!!! Nice tidy little forge.

jompon2547 (author)2017-11-08

amazing

but can i use cooking gas instead?

Marsh (author)jompon25472017-11-08

If you mean Natural gas from your house, no. Not with this burner. Natural gas requires a different sized orifice. You may be able to modify this burner, but I don't know how...yet.

oldfatnbroke (author)Marsh2017-11-10

You can pick up gas jets from pretty much any place that services or installs gas stoves or heaters or even gas fireplace logs. The orifice for propane is a lot bigger than for natural gas but they use the same size threads so they are interchangeable.

CB71 (author)2017-11-07

Which was the "$50" part?

Marsh (author)CB712017-11-07

I'll indulge you since you didn't wish to see the repeated references in the other snide comments. $20 for ALL of the brand new firebrick, $20 for the brand new weed burner, $10 for remnant steel from a local steel yard. It was actually closer to $45, but I rounded up just for you.

CB71 (author)Marsh2017-11-07

OK, I understand that you have the ways and means to construct this forge. With a plasma cutter, mig welder, portable band saw, and a bunch of extra steel laying around it does seem to save on cost. What I see as a way to cut cost, not reliability, is wrapping a piece of rusty old speaker wire around the weed burner. A solid structure for the burner to be secured by seems to be adding to this type of hard structure.

Marsh (author)CB712017-11-07

It is clear from your comment that you not only did not watch the video, you also did not read the Instructable! If you're going to make comments, actually reading the material you're commenting on would put you in better light. For instance, the minimum complement of tools required to make this project is an Oxy/Acetylene torch and a drill with a masonry bit. This can be found in THE VERY FIRST LINE OF INSTRUCTIONS, which you obviously overlooked. A plasma cutter was not used in this project and all of the material was purchased BRAND NEW for this project for less than $50! The steel were remnants, but it was still brand new.
It appears you're just looking for something to complain about. All of your dramatic/iinflammatory assumptions are incorrect, and you would know that if you had read the Instructable.

TreyH17 (author)Marsh2017-11-07

Greatest. Reply. Ever!

dbenedetto (author)TreyH172017-11-07

Amen. Great minds will always be attacked by small minds. I forget who said that.

Carl TomasA (author)dbenedetto2017-11-10

...

"Great minds discuss ideas, average minds discuss events, small minds discuss people" ... Eleanor Roosevelt ...

AaronB267 (author)Marsh2017-11-08

You have no need to defend your price. If people are to lazy to shop around then they will have to suck it up. Good build. Keep it up.

Cwren10222 (author)2017-11-09

looks like a great forge. Forget the haters comments. If it heats the steel to a nice orange that can be formed then it's a great design. I've got all the components laying around sans fire bricks to build one as scrap from a previous project but sadly my old stick welder quit so gonna have to budget in a new welder from harbor freight myself so mine may cost about $150 to build including the new welder but looks like a fairly simple design that will do the job, is relatively portable and will take up minimum garage space. Keep em coming just like this.

deepforest (author)2017-11-07

Marsh, well done, that was a great instuctable and more so a great concept. Thank you for sharing.

Folks if you can see the benefit of sharing concepts and ideas, then please play nice. Point scoring, grand-standing squabbling and bickering over minutia that I see here is exactly the type of thing that eventually destroys great forums such as instructables.

Does anyone know if treating pizza oven fire bricks with waterglass would improve their thermal profile for this type of application? Water glass is easily made from silica gel (do not eat - dry packs) and caustic soda (NaOH)

Hola. El vidrio líquido solo se utiliza en el interior de las ollas o vasijas de barro. Pintando el interior de las mismas se evita la rotura temprana de la olla, ya que al ser de barro y quizas al no estar apropiadamente "curada" (termino que en cerámica se asemeja al templado de los aceros). En el caso de su horno de pizza no hay cambio en nada la temperatura por el uso de vidrio líquido en los ladrillos. No vale la pena pintarlos. Si desea tener más calor verifique las perdidas de temperatura que se encuentran entre los ladrillos del horno mismo. Busque una pasta que tolere las altas temperaturas y no se quiebre ante los cambios de temperatura.

Saludos desde Argentina

Thank you.
I had not thought of making crude pots using waterglass.
I will have a play with that Idea.
Greetings from Australia...

RandyKC (author)deepforest2017-11-08

...”treating pizza oven fire bricks with water glass would improve their thermal profile”...
Short answer, no.
Water glass is used in many refractory builds as an adhesive but isn’t a good insulator by itself. It is used with vermiculite or other minerals as a binder when making refractory panels. You would probably degrade your pizza oven fire bricks (working temperature of about 2400-2500 F) by coating them with water glass and the surface would probably start flaking off with successive firings.
I’d love to see an instructable on how to make waterglass. Real useful stuff!!

ClearCaseMan (author)2017-11-07

where did you get your firebricks? those will be over 50 just themselves

Marsh (author)ClearCaseMan2017-11-07

People keep saying this. You folks need to learn how to shop. They were $1.60 each at my local brickyard.

Poppy Ann (author)Marsh2017-11-08

I have met many people who need lessons in how to shop, most people see a sign that says 50% off and believe it is a good deal without ever having a look around elsewhere, once when I was in Guatemala sat in a bar a guy came in to talk with the owner telling her that he had got het a good deal on a new alternator for her boat when he said the price I almost dropped my beer he said $475 plus shipping and had a straight face I could not hold myself back and told her to give me a couple of days and I bet I could get one for half of that I checked with a company back in UK and they said they can have one delivered in 48 hrs for $78 including shipping after that the guy doing the work would not speak to me but the alternator was there in 2 days, it just goes to show if you dont look around you will end up paying as much as the seller thinks he can get away with not what the item is worth.

RandyKC (author)ClearCaseMan2017-11-07

The author would know best, but these look like fireplace bricks. Those are the bricks that you use to line your fireplace. The really expensive bricks are kiln bricks. In this application fireplace bricks would be more abrasion resistant. I don’t know the maximum temperature they will withstand but it should be within reach of the propane weed burner setup.
Will the author use this to forge knifes?

Sparvar (author)2017-11-07

Excellent instructable! Everything you said and showed in the pictures is easy to understand and looks very effective. I'm not able to build this at this time, but I'm saving it for future reference. It's fantastic!

astrong0 (author)2017-11-07

I actually used mine last night. Love it. I used ceramic fiber insulation though. Different heat capacity.

deepforest (author)astrong02017-11-07

Great Idea mate - thanks

oky jim (author)2017-11-07

I'm an old timer and I remember my grandfather heating wagon tire material to temps hot enough to nhammer weld them. He also hard faced his plows with baling wire and a home built welder that used carbide for fuel.

MattF87 (author)2017-11-07

What size weed burner did you use? I see a wide variety from 20k BTU up to 100k BTU available.

Marsh (author)MattF872017-11-07

500k BTU. $20 at harbor freight

toxonix (author)2017-11-07

The atmospheric burner firing up from the bottom is how I like it. I make my burners using iron pipe and brass MIG welding tips for the propane nozzle. The burners last forever if they're not actually IN the forge atmosphere and are firing up from the bottom.

dpatterson13 (author)toxonix2017-11-07

I'm unclear on the brass nozzle, I thought the nozzles were made of copper, can you post a pic?

GTO3x2 (author)2017-11-07

I would call this an oven or furnace. Forging is the smashing part, not heating.

Jdstock0713 (author)GTO3x22017-11-07

Forging:

make or shape (a metal object) by heating it in a fire or furnace and beating or hammering it.

You are all right dang it.

CindyM105 (author)GTO3x22017-11-07

This is for smithing do forge is correct term

74shovel (author)GTO3x22017-11-07

Forge is the proper name.

MattY40 (author)2017-11-07

I think I might build one of these. Have you ever gotten steel up to welding temp with it?

TeeganH (author)MattY402017-11-07

we have one built at home slightly different and we're unable to forge weld in it. great for making s hooks and bottle openers, but a coal forge will really be where the heat's at.

Marsh (author)MattY402017-11-07

I've not tried to weld, but I can get it glowing orange so it won't stick to a magnet.

jdziki (author)2017-11-07

Hmmmm, pizza oven.

Xexos (author)2017-11-07

Nice work! I love the simplicity, this would be great for allowing a beginner to get into blacksmithing. One thing I will say, you can build a better burner for cheaper than $20 out of plumbing parts. Looking at the pictures, your weed burner is producing a lot of exhaust which means that a lot of propane is being burned that doesn't actually help heat the inside of the forge (this isn't necessarily a bad thing because it means you are running a reducing atmosphere in your forge, but you'll lose a ton of heat this way). I know there are a couple great instructables on how to make a venturi burner, you may want to give those a look at some point! Have fun smithing :)

Marsh (author)Xexos2017-11-07

If you use a firebrick as a front door to hold the heat in, it gets a lot hotter. In any case, it get's plenty hot enough to do what I want.

ajayt7 (author)2017-11-07

Good idea, great job!

geneguru1 (author)2017-11-07

Excellent. I've been wanting to make a forge, but didn't have the specifics or the "blueprint" for it, so now I will put one together. Thanks much.

Lorddrake (author)2017-11-06

what sort of temperatures are you able to achieve / maintain with this forge?

how do you keep the trigger for the weed burner depressed, or did you remove that part?

Marsh (author)Lorddrake2017-11-06

I don't have any equipment capable of measuring that with any accuracy, but it will heat steel hot enough that it glows orange and won't stick to a magnet. Hot enough to pound into a blade.

mahruk (author)Marsh2017-11-07

You can always use a Heat Stik. They melt at the indicated temperatures. You can get them at markal.com/temperature-indicators/thermomelt

Wonderful 'ible. I have been thinking of making a forge for a while now for my own attempts at smithing.

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Bio: I'm an environmentally conscious experimenter who loves to bring people together, build things, and when possible...blow things up! See us on YouTube too ...
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