Folding Chair Charcoal Forge





Introduction: Folding Chair Charcoal Forge

The Folding Chair Forge is a compact fully-functional blacksmithing forge that can be used from anything from forging medieval hairpins to swords. It comprises two fire-proof bricks, a folding chair, a couple of brackets and a hairdryer and folds up so that it can be stored in a corer, or hung up on a wall. Depending on the type of folding chair you have, and the equipment you have at hand, the project can be built in an extended lunch-break.

Step 1: Find an Old Folding Chair

Depending on the seat, you may need to replace the seat with a flat piece of wood. We (together with my 11 and 14 year old sons Paul and Max) did that for this chair as the seat was curved. Using the seat as a template we drilled the holds for the fittings and then attached a plank that had been cut to size, and added additional pieces to ensure that the next step (the baking tray) would be level.

Step 2: Add Your Baking Tray (or Other Piece of Sheet Metal) As a Spark Shield to the Chair

We found an old baking tray used a hacksaw and tin snips to make space for the metal pipe. If you use a flat sheet of metal, there will be no need to cut anything apart from the actual sheet of metal. While the design might not have your forge going up in flames without this step, it generated sufficient sparks to damage the wood over time, so this step should not be omitted.

Step 3: Choose a Pipe for the Airflow, and Drill Holes

The pipe should be large enough to not melt, we chose a galvanised pipe from the local hardware store, added a cap to one end, and drilled 1/4 inch holes roughly 2 inches apart.

NOTE: While we used a galvanised pipe (was all we could find) some have responded here that it can give off gases if heated. Although the pipe never gets particularly hot, if you can find a regular iron or steel pipe it would be better.

Step 4: Add Your Frame for the Fireproof Bricks and the Pipe

We used brackets as a simple, readily available solution to the problem of having a right-angle to support the fireproof bricks. One large bracket forms the 90° angle required, and each is supported by two smaller brackets.

Step 5: Add the Pipe and Your Fireproof Bricks, Your Forge Is Now Almost Ready!

We bought two fireproof bricks from Amazon, probable much cheaper ways of doing this but they are heat resistant to around 1200°C, so should last a long time. Do not use concrete, it contains water and can explode. Also I would advise on spending a little more for good bricks as this is the most expensive aspect of the entire project, but also the most critical.

Step 6: Connect a Pipe to Your Hairdryer

We used an old hairdryer as I had seen on other forge projects and it worked beautifully. We also attached the metal pipe of a vacuum as it fit nicely with the pipe used for the forge, and was long enough to keep all heat away from the hairdryer. When fully fired up, the pipe never got hot, not even close to the forge, so the airflow alone seems to have been sufficient.

Step 7: Unfold and Fire Up Your Forge

Once connected, take your forge outside and fire it up. We used regular charcoal and it heated up nicely, allowing a good yellow heat in the metal and us to forge the rough knife in the next step (which we will now refine).

Step 8: Forge a Knife, Then Fold Up Your Forge!

Here is the knife previously mentioned (now available as an instructable). It is very rough and now needs to be refined, then heated, tempered and so on, but you see the effect. The steel was initially a rod, and the effort required was not particularly great to get it into form. The forge exceeded my expectations, and is now conveniently folded up in my workshop! As you will see from the picture the firebricks, metal pipe and hairdryer are not attached to the folding chair (yet!). We aim to further refine the forge and have everything connected, but wanted to get this instructable out there. I look forward to hearing your suggestions and comments! Happy forging!



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    29 Discussions

    Wow! I have been smithing for a few years and I thought I had seen some nifty forges, but I think this takes the cake! I love the low cost and convenience of it. I'm going to suggest this for any of my new students who are looking to make their own forge. I might make this myself.

    Three suggestions, hopefully not repeating what someone else said, look for a local plumbing shop for the black steel pipes (that's where I had to go for mine, Lowes and stores like that don't carry non galvanized or non zinc coated as often), block the side(s) so you can keep coal/charcoal near the flame so it heats up and dries so it can be ready to throw right in the fire as well as help contain the heat, and control the air flow. Its obvious that you where able to forge the knife but I think if you either use a pipe with less holes (putting holes towards the center, not the edge) or block some of your holes you'll get more air, aka heat, and be able to control what gets hot better. Less holes would also help to prevent coal/charcoal from being wasted when you are only heating a smaller portion.

    What might work well with your set up is to forge yourself some rivets and place them in the holes you aren't intending on using. Just don't set them and you can pull them out and move them around. They should effectively stop the air flow (or at least most) and allow you to take them out so you can heat up larger projects. Just periodically check them to make sure they don't weld onto the pipe.

    2 replies

    Thankyou for that feedback ARKtest! You are right, I wanted to get another firebrick to put at the end of the forge. Regarding your airflow suggestion, I considered using some bolts (and threading the pipe), but I will get the black steel pipe before hand now. When I have made final modifications (so the bricks and pipe can be stored on the forge as well for storage) I will post the final steps, but had to get this up there following a successful run of the forge! Really appreciate the ideas!

    I'm glad I could help. I might not suggest using threaded holes because the clinkers that form will make cleaning those holes difficult. I use a black steel cap with holes drilled into it for my air flow. it has two holes that sealed up completely because of clinkers. I have to drill them back out, I wouldn't be happy to drill it out and thread it again.

    A clinker is the molten metallic slag (waste) that burns off of coal and your metal that makes its way down to your air source inevitably clogging holes. My mentor's forge has a large round hole that eventually makes a pancake sized, bowl like clinker. Its kind of cool but if you forge for some time and your air flow starts to die down, it might be a clinker.

    If you do find yourself with some clinkers and its iced out where you are crush them up with a hammer and put them in your truck. They are excellent for giving you or a friend grip on ice if you're stuck.

    Not joking about that concrete warning, I built a foundry and poured aluminum into a baking tin mold on top of a concrete patio. The mold started to dance around on the patio, leaving behind little pits and sandy shrapnel where the concrete had popped, and nearly toppled over. Have to be careful with heat like this, and MUST have the right materials.

    1 reply

    so. how well does this work? have you made anything with it that we can see?

    I've worked with aircraft structural materials for over 35 years I am a structural Craftsman. We work with the welders in the USAF and I've always been amazed when they did hearteeatment and blackamithing. Now I'll be able to try my hand with this awesome forge that you have designed. I've been searching for one that I could make easily and for a reasonable price. Thank you for this.

    Brilliant concept and well executed. One serious flaw that gives me serious concern is the use of galvanised pipe for the burner. This could be lethal replace it with black metal pipe asap. Galvanised gives off fumes including derivatives of Cyanide when subjected to high temperature even if used outside this can have serious consequences with just a gust of wind

    3 replies

    Thanks trapper23, the pipe is not actually in direct contact with the flames (perhaps the occasional spark) and as the cold air that flows also cools it, it did not seem to be particularly hot at any time (certainly not glowing hot, which is where vapours are the most likely). So I think we should be fine from in terms of health. However as I have heard that a couple of times now I will certainly look into replacing the pipe, and advise anyone who wants to craft their own folding chair forge to consider the potential risks involved as well. Thanks for your concern and compliments on the design! Much appreciated.

    [see for more on zinc metal fume fever]

    I have now added the following note to the instructable for anyone planning to build this forge. Thanks all for your comments on this.

    NOTE: While we used a galvanised pipe (was all we could find) some have responded here that it can give off gases if heated. Although the pipe never gets particularly hot, if you can find a regular iron or steel pipe it would be better.

    Easiest solution is to torch off the zinc layer while outside. Not that big of a deal to deal with galvanized steel.

    1 reply

    Kinnishian, I lost a friend to zinc metal fume fever (see for a writeup). If one has a small amount to do and the wind is blowing I could imagine what you suggest as being safe, but would strongly encourage folks to just buy the non-galvanized stuff.

    Very nice work-- but one suggestion, and this needs to be implemented right at the beginning, please. Your entire forge's weight is based on two little bolts going through two pieces of frame down where they intersect, and this begins with 'take an *old* folding chair'; how strong are those bolts? How good are the nuts? How strong is the frame at those two intersections? As someone who had to help bandage up a coworker when the old chair he was sitting on collapsed under him (not a particularly big guy, the chair was just old), I can guarantee that those intersections are where the chairs breaks. SO: Any time you plan on building something from something else (especially something capable of spilling hot metal and coals onto your feet and the surroundings), check the stress-points! Replace the bolts, check just how much weight the chair can actually hold, and if you're unsure about it... don't use it. Thanks.

    2 replies

    Thanks ysabet, good point. The chair I chose was still fully functional and robust, the weight tested and more than capable of holding a 100kg person. The total weight of the forge is probably not more than 20kg. Of course, if you have a very poorly made, or particularly old chair it would help to further fortify the frame. Thanks for sharing, good point!

    De nada! I have injured myself in far, far too many ways in the past due to going I MUST MAKE ALL THE THINGS RIGHT NOW and not checking the primary catastrophe point: the weight-bearing strut. I have lovely tattoos covering burn-marks on my left hand, a scar on my arm from a near miss with a loose sanding-disc that almost cost me part of my ear, and molten-metal burns on the top of my feet... so I tend to think about these things. Well-- I tend to think about these things *NOW*, anyways! Ahhh, what's a woman to do without a hobby? ^_^ Take care.

    Wow!! GREAT job! One of the best homemade setups for a small charcoal forge! Keep up the good work!

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    I love it. My one and only forge project was when my son was at the lumber yard with me 20 years ago. He asked if they sold long sticks there. I said yes and asked him what he wanted to build. He sheepishly said a spear. Being a sucker for kids inventing I said OK lets build a spear. We picked up a clothes rod for a shaft and were gifted 8 inches of rebar. Next we went to my store and scrounged an old central vacuum cleaner. We took out the motor for a blower and used the tank as the container for the fire. Using some vacuum wands we hooked up the vac to blow into the bottom of the tank. Using some scraps fir 2x4's we forged a spear point. The best part of the lesson was after attaching it to the shaft we took it to our archery target. Normally an arrow could penetrate the target and some would go through the bales of hay and stick in the 1/2" plywood as a backer. He threw the spear then I threw it and it penetrated the target, hay plywood and fence. I then understood why the natives used a lance on big game instead of a bow. The massive weight of the shaft stored more energy than my compound bow.

    Thanks for bringing back a fond memory. Twenty years later I still use his spear to dig out weeds in the garden.

    1 reply

    Thanks for sharing that story! I bet those weeds whisper in low tones and terror!

    I built a forge when I was 14 with my 17 year old friend, who had some experience with metal work. We used an old truck wheel, a plate of metal and an old vacuum, welded it all together and fired it up. It worked very well, was fired with mineral coal, and managed to melt some rather thick pieces of iron (almost a foundry more than a forge). A couple of years later I did work experience with a medieval blacksmith, and those two experiences have stayed with me, despite working in the software industry with nary an opportunity to forge for anything but personal joy, and remain some of my best memories. I wanted to share that feeling with my boys, and I am confident that they will regard the memories in a similar way, one day perhaps, building a forge for their own kids!