How to Make a Bladesmiths Forge





Introduction: How to Make a Bladesmiths Forge

In this Instructable I will be explaining how to convert that old barbecue grill sitting in your yard next to all that junk into a furnace capable of heating up steel to forge long items such as knives,daggers,and small swords. Before we begin I would like to say I am not responsible for any injury or damage caused by reading and/or following the instructions in this Instructable and working with hot items will always have associated risks. I would like to give credit to Tim Lively as I watched his movie called Knifemaking Unplugged and have based 1 of my refractory mixtures and the design of the forge off of what he uses. Great movie. I ordered it off of Amazon Unbox.

Step 1: Clean That Crap Up!

First we will want remove all the internal components such as the rack and burners. Strip it down to the bare grill body. Remove all knobs and such so that all you have is the metal grill. Remove and throw out the handle, if it is plastic. Now we will use a blowtorch to heat up the grease that has accumulated from you chowing down. We will heat up a section of the grill with the torch and scrape the the heated section with a metal scraper. Now we will heat it again and this time we will wipe it down with a paper tower. Once your satisfied that it is nice and clean proceed to spray it with oven cleaner, just to make sure. Let this sit for a while and then spray off with a hose. Let the grill dry.

Step 2: Constructing the Tuyere

Now we will construct the tuyere. The tuyere is a pipe that delivers an air blast from a blower to the fire that allows the charcoal to heat faster. We will need black iron pipe 1 1/2" diameter that is just a little longer than the length of your grill. We will also need a 1 foot section of 2" black iron, a 2 - 1 1/2 reducer coupling, and a 1 1/2 end cap. Now we will put the 2 inch pipe into the reducer and screw it on. Now we will screw in our 1 1/2 inch pipe into the reduce. Now we losely screw the cap on. The cap is to allow for easy clean out. Now we drill holes in the pipe every inch about 1/4 inch or a little less. Remember the more holes you have, the more oxygen to fuel the fire but, also the bigger a blower you need.

Step 3: Adding the Tuyere

Now that the grill is dry, we will use a circular hole saw and cut as close to the bottom off the grill n the center on both sides. Make sure the hole is just large enough to accomodate the tuyere. Slide the tuyere in and screw the end cap on.

Step 4: Adding Refractory

Of course, to keep the forge body cool enough so it is not damaged, we need a layer in between the fire and the grill. I will use Mt Savage refractory cement, although you may use 1 of the following recipies, a 1 part furnace cement and 4 part perlite or 50/50 of sand and clay. We will want to fill the forge right to the tuyere and have a 70 degree angle upwards to provide a trough to hold our fuel and blade. Let dry.

Step 5: Get Fancy

If you haven't noticed, I have been fancy with my grill and added a plywood shelf underneath to hold my charcoal and tools and I have added a small plywood table where 1 of the plastic ones used to be. I will be adding sheetmetal to the plywood surface to keep it cool.


Now we will load it with charcoal and light it up for use. We will begin by adding some newspaper at the bottom and then placing small dry wood kindling on top of it. Next we will top that with charcoal. Preferably homemade charcoal as it burns better, doesn't stick to your blade, and it has less flying debris. Light the news paper and wait for some of it to catch fire and then turn on a blower device connected to the 2 inch pipe. I personally use a shopvac. Enjoy. Be careful. If you now have a forge but no idea how to make anything, stop by or and buy Knifemaking Unplugged. And im sorry but i have no photo as all this was taken while i was waiting for the cement to cure.



    • Water Contest

      Water Contest
    • Creative Misuse Contest

      Creative Misuse Contest
    • Oil Contest

      Oil Contest

    102 Discussions


    9 months ago

    How do you make sure that the tuyere does not collapse due to the iron being heated to its working temperature?


    10 months ago

    how much would it cost for evrything except the hardware plyboard and grill

    I'm intrigued by the suggestion to drill holes in the tuyere. How does that supply additional air if you already are using a blower?

    I'm planning to try something different with a similar grill body. I want to line top and bottom and add three gas burners. Will I need a tuyere and air with the gas burners?

    Just finished building one of these for my son and me. Because I can't throw anything away the whole project cost me only $3.55 for the play sand (had the plaster already). It took about 3 weekends to make (2 actually working on it and 1 watching the plaster/sand dry ((should have given it 1 more developed hairline fracture)). I try to make my son do as much of the work and the problem solving as possible, no matter how painful it is watching him trying to get a self taping screw started. It was a good father son bonding project. We've already started our first knife. Next project: pneumatic Planishing hammer. Get to teach the boy how to weld ?


    Couldn't an old natural gas tank with a lid cut into it work just fine if you layered it with protection

    so, to get that straight, you could just line the inside with cat litter? instead of paying $100 a bag?

    13 replies

    In theory yes... i have heard of clay cat litter mixed with water to form a slurry which is then evaporated to leave u with a regular consistency clay which is then placed in there. In practice..i would not...the work of making a slurry and drying it and then placing it in there to have it crack after a few uses and then buy a new bag is the downside. id imagine with the labor and and price of litter eventualy ull add up to the same price at the stuff that basically never needs repair.

    i've been pondering for a wile..... could u use dirt turnd into varry thin mud almost like slip so theres no dry spots and then boil it down to a really really thick mud and then use that?

    ahh, well, i really only want to make one thing with the forge: a straight edge knife/razor for hair shaving. do you think i'd be able to make it after just one attempt? or...not? haha

    Well all i can say is you can try. The tough part wont be shaping it. The toughest part will be making it go from looks to function. You would need a very fine edge and would need great sharpening equipment ranging from course to honing gear... out of the 5-10 ive made i havent acheived that sharpness...but ive acheived decent blades that dont dull easily..all im lacking is handle making. lol

    I've got a bench grinder (don't remember the specs right now :/ ) and a dremel, do you think i'll be able to make it work? because i can get the railroad spike(s) i plan to use for free, and the forge i could make easily i believe. (the strop too i can make) and the sharpening stone(s) i believe my dad might have ATM would probably work...
    do you think i could take it to a local sharpening store and have them put an edge on it? because even if they charge $20-$50 to put an edge on it, i still think that it would be at least equal or even better to/than what i could buy with the same amount of money.

    Railroad spikes are made of medium carbon steel which means they have a medium hardness. They probably won't hold an edge well enough for a razor. They work great for letter openers and so forth, but you need a steel with higher hardness to get a real sharp knife. One thing that I use a lot for knives are old files. Just make sure they are hardened the whole way through and not just case hardened. Also, check out some knife making forums for tips. After you shape the blade you have to reheat it and quench it in oil to harden the steel. You also have to temper it at a low heat after quenching so it isn't too brittle. Good luck, hope it works!

    well its possible... but its gonna be pretty difficult...i would not reccomend starting with a rail spike. Some of the spikes MAY be high carbon steel but getting it to the thickness is alot of work especialy if you have never forged before.  My advice would be to either get some basic stock like round stock and hammer it flat (dont get it very thick) OR get flat stock the thickness you desire and cut it out with a hacksaw or other tool. Straight razors are one of the finest edged tools that a common person would use on a daily basis. They require a great first sharpening and then great maintence following it.  I have taken a qoute from another article on this to share with you.

    'Sharpening is the final stage in the process. At first the blade is sharpened on a grinding wheel. Following that the blade can be honed by holding the blades against the flat side of rotating round stones, or by drawing the blade across stationary flat stones. The cutting edge is finished using a strop."

    So the idea behind it would be to go from a quick edge using a somewhat fine grinding wheel on your grinder or a stationary stone. Be carefule in doing this cause excessive heat that can turn the steel colors is bad for the integrity of the blade. The you would move up to different courseness of arkansas stones until you get it pretty fine. Then from there you would use a strop possibly with polishing compound on it to finish the edge. You may be able to get a shop to do it for you but make sure to discuss the use of the blade with them before having them do it so you know what they are able to make the blade do. I have a railroad spike knife myself and let me tell ya..with a good amount of work its still pretty call it more of a chopping knife due to the thickness.

    hmmm ok, sounds like i might have to put out a little more money than i was expecting. oh well. so: to clarify, i'll need a piece of: high carbon flat stock, and then forge it? or just use a hacksaw on it? (i'll be making my own strop btw haha)

    sorry to repeat but i'll need to buy:
    1 piece of high carbon flat stock STEEL? or IRON?
    and then: FORGE it, or just CUT it out?

    also, there's a barber that uses a straight razor on campus. he's been there for 50+ years. im betting he'd be able to hone a fairly dull razor.

    btw, how much do you think a piece of stock will run me? (in USD) can get thin round stock and hammer it flat and to shape OR get a sheet of flat stock and cut it out in shape...then you would want to sharpen it to the best of your abilities...these razors come sharp and they r only maintained sharp..they are not really resharpened by a barber..he keeps them sharp with the strop. If you get it to a pretty good edge he may be able to do it for you OR tell you how to sharpen as you want it. Ive never really bought steel...all my stuff is recycled. You want a flat stock as thick as the BACK UNSHARPENED edge of your razor will be and from there u grind the edge you want and do all the sharpening tricks to it.

    You either want 1 peice flat STEEL stock or 1 peice round steel stock and forge it flat and work with it

    i think i'll just get a sheet of thin flat stock. I'll let you know how this all works out in a couple of weeks when i get back home to my tools! 

    oh, and i saw on youtube a video of a guy making wedges from wood for a straight you know what those are? just curious haha

    sunds good! you will have to post a pic! and i have no clue on that 1 lol

    Oh, i'll DEFINITELY be posting a picture :)

    but, i might be using a differant forge :S sorry! i don't have this readily available...probably going to bury a piece of pipe in the ground and then drill holes in it, dig out the dirt around it, then line the sides around it with red brick.