So you want to make a forge, but you don't have much time or money to build something state of the art. I think every beginning blacksmith has been there. It's tough to figure out how to make a structure that will hold up to high amounts of heat and still stay functioning without having to spend a large amount of money and/or hours of time to get it. Well, this is a step by step guide on how to build a small forge that will handle basic blacksmith projects for virtually free. I made it using old junk salvaged from around the house. I had everything lying around so cost for me was free, but I'll also include a shopping list with prices for parts as well for anyone that either doesn't have a deep junk pile, or wants everything to be shiny and new. Let's get started!
Step 1: Caution and Disclosure
Please note, you are about to build a forge that has the capability to melt steel. Please use caution while constructing and using this forge. I take no responsibility for any harm to you, someone else, or your property that you cause through the use of this instructable.
Full Disclosure: the pictures used in this guide are actually pictures of a rebuild, not an original build. Due to being out in the elements, the original forge started to break down after about three years of use. That being the case, you'll notice some reused elements like a mixture of coal dust and dirt in the play sand and some already broken bricks being used in the construction. Just wanted to make sure I didn't deceive anyone.
Step 2: Materials and Tools
- Red house bricks. The forge I built is three layers tall with about six bricks per layer plus about four more on top so a total of about 22 bricks. Obviously you'll need more if you want to make it taller. Other types of bricks may work as well, but the red ones are what I have readily on hand and I know they work. Fire brick would definitely work, but we're talking cheap and/or free here. Definitely don't use concrete.
- Play Sand. Around $3 for a 50 lb bag which should be more than enough.
- A length of pipe. A 1/2" diameter by 5' long conduit pipe (which is what I use) can be picked up at Lowe's for about $1.50. Whatever pipe you use, make sure it is steel and not copper or aluminium as they will melt under the heat produced.
- Metal grating of some kind. A grill grate would work. I've used
everything from thick gauge chicken wire to a wire fridge shelf. A brand new grill grate will run between $10-30.
- A pipe elbow that fits your pipe. 1/2" in my case. I use simple black iron pipe fittings and they run about $1.50 at Lowe's
- A pipe end cap. Again, mine is 1/2" black iron pipe and works fine. About $1.50 at Lowe's.
- An air source for a bellows. I'm currently using an old air mattress
pump, but I've also used a hairdryer, a box bellows, and a hand crank bellows. All of them worked at least decently. Prices range from free to $100+ but an air mattress pump will run around $20.
- Duct tape. If you don't already have a roll of duct tape in your home,
shame on you. Go buy one. A new roll will cost around $3.
- A drill and bits
- A hacksaw or other metal saw
- A trowel
- Your hands
Step 3: Pick Your Location
Choose a spot that is a fair distance from anything flammable. I don't recommend a garage or small workshop due to flying sparks and high temperatures being a factor. Mine is set up beside the backyard garden. Even out there I've managed to set dry grass on fire several times, resulting in a small scale prairie fire in my own backyard so please choose an open spot with nothing seriously flammable around it. Also make sure it's level because this will save you the trouble of having to level it out yourself. Last but not least, if you are planning to use a bellows (hair dryer, air pump, etc.) that requires electricity, consider the proximity to the house or workshop as you will need to run an extension cord from an outlet to your bellows in order to make it work.
Step 4: Lay Your Bricks
Begin laying out your brick pattern with the first layer. I just use a simple square shape. Make sure to leave a gap between the front two bricks for your pipe to sit in. For my bricklaying, I use a simple overlapping pattern with two bricks on the front and back, one brick between them in the sides, then the opposite on the second layer and so forth. This helps lock the bricks on the corners, making a sturdier structure. There are probably other, better ways to do this, but I'm not a bricklayer and this works pretty well. Whatever pattern you choose to use, make sure your bricks overlap or they won't hold together and you'll wind up with a brick pile again. Anyone who has ever played with building Lego houses has figured this out. Build up as many layers as you want. Like I said before, mine is pretty humble at three layers tall, but it gets the job done.
Step 5: Construct Your Air System
Definitely the most complicated part of this build. Take your length of pipe and cut a piece that is about the same height as your brick structure. This will serve as the air delivery for your forge. Take the longer piece of your pipe and twist it into the elbow. The pipe will probably not exactly thread on, but twist it as if it were threaded in order to get the fitting to bite in and give a tighter fit. Take your end cap and drill a series of holes in it, Then attach it to the end of the shorter pipe. Again, the end cap will probably not exactly thread on, but it will work just fine. Slide the long pipe, elbow end first, through the gap we left in the bottom front of the brick structure then twist the shorter section of pipe into the open end of the elbow.
Step 6: Pack in the Sand
Take your play sand and pack it around your pipe inside the brick structure. Make sure the pipe is standing upright and is at least close to the center of the brick structure. For a tighter fit, feel free to pack sand into the gaps between the bricks too, but it's really not necessary.
Step 7: Place Your Grate
Set your grate on top of the brick structure and anchor it down with bricks or brick pieces. This will both hold your grate in place and create sort of a railing to keep your projects and fuel inside the forge.
Step 8: Connect the Bellows
Put the blower end on the end of the pipe and duct tape them together. This is obviously pretty primitive and also requires a small sacrifice of duct tape every time you need to remove the bellows for any reason. You could probably rig a different system with pipe fittings, but this is what I do and it has worked well so far. The blue thing in the picture is another type of bellows that works by rotating a hand crank. I picked it up on eBay for $50 or so, but I prefer the mattress pump because it allows me to do other tasks between heating and working on pieces. If electricity is a concern, though, or you just want to be a little more primitive, this is a great alternative.
Step 9: Fire It Up!
Once you've got everything connected, all that's left to do is start your fire. Build a small teepee of sticks around a fire starter like paper or cardboard and light it like you would a campfire. Add charcoal, coal, or wood to your fire as it gets hotter and larger. Turn on your bellows when you have a decent heat started and get to work on your projects!
Step 10: Final Notes
Obviously this is just a template. Throughout, there are probably better/different ways to do almost everything, but this is the way I built mine and I have made over 100 pieces on it from small pocket knives to full size swords to pendants to hammers. The single bellows reliably gives about a six to seven inch working heat meaning that this is about the size of the area you'll be able to work on at a time. More elbows and pipe ends might make the working area bigger, but I've never tried. The temperatures I've reached in this type of forge have been high enough make forge welds and even melt through steel bars at times so basic forging heats are no problem.
Also, a note on fuel. If you want the best heat and easiest use, buy some coal. It burns the hottest and works the most efficiently but it's more expensive. If you want a slightly cheaper fuel that is still pretty efficient, get some cowboy charcoal from your local hardware store. This burns quicker than coal and shoots sparks badly, but it works pretty well. Don't use briquettes. They work in a pinch but they don't work well. Last but not least, if you want dirt cheap, inefficient fuel, use chopped pieces of wood. These spark worse than the charcoal, are not highly efficient, and put out a lot of flame as opposed to coals leading often to burnt fingers, but wood is easily accessible and sometimes free. I've used all three and my favorite is a mixture of coal and charcoal, though I've been using mostly charcoal lately due to availability and my own laziness in getting more coal.
Last but not least, note that the bricks near the top of the forge may need replaced periodically. Red bricks withstand heat fairly well but they'll still break down over extended periods of exposure to high temperatures and outdoor elements. Good luck with the build and have fun!