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!