Introduction: How to Make a Bladesmiths Forge

Picture of 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!

Picture of 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

Picture of 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

Picture of 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

Picture of 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

Picture of 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.


720545 (author)2017-10-03

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

RexS10 (author)2017-08-31

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

HenryFrapp (author)2017-01-17

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?

ghostrider31622 (author)2016-05-03

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?

jimwhite (author)2016-03-19

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 ?

gahimer (author)2015-07-20

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

Gksarmy (author)2010-04-16

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

trf (author)Gksarmy2010-04-16

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.

Gator1070_ (author)trf2011-09-10

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?

MrDarkNebulah (author)Gator1070_2015-07-16

If you are looking for a cheap alternative a 50/50 mix of plaster of paris and play sand works perfectly.

Gksarmy (author)trf2010-04-16

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

trf (author)Gksarmy2010-04-17

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

Gksarmy (author)trf2010-04-17

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.

14bwenger (author)Gksarmy2015-02-16

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!

trf (author)Gksarmy2010-04-18

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.

Gksarmy (author)trf2010-04-18

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)

trf (author)Gksarmy2010-04-18 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

Gksarmy (author)trf2010-04-18

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

trf (author)Gksarmy2010-04-18

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

Gksarmy (author)trf2010-04-18

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.


trf (author)Gksarmy2010-04-19

ive seen that done but it is last design was a large steel cake tin lined with clay with a pipe drilled into the side and just blowing it in from a hair holes.... just straight out the end... it was able to heat up a peice of rail spike..not the most efficent for a large knife so i made that new 1.... ive also seen small steel utility tubs u can buy em at homedepot..its just basically a rubbermade container but its steel instead... line em with clay and put a pipe through

Gksarmy (author)trf2010-04-19

haha, im just not wanting to pay the $100+ for the razor :P
i still LOVE the idea of smithing, but i just don't have the time/space to get into it as much as i want to right now :/

trf (author)Gksarmy2010-04-19

I doubt it would be that much... if u just wanna start off... fine a peice of scrap steel,a cake tin at walmart for a few bucks,a regular hammer which im sure u have acess to,a hard peice of steel (in my case it was a railroad plate on a tree stump),a small peice of pipe,a hair dryer,a pair of good pliars to grip the metal,some work gloves...drill a hole through the tin and put the pipe through,clay around the bowl and pipe to make a clay liner,put the blow dryer on the outside end of the pipe and duct tape it on and duct tape it to cold. add charcoal and light it and turn on the hair dryer. let it get hot. drop steel in. pick out with pliars. hammer on tree stump steel. reheat. its a very simple and cheap set works on SMALL stuff

Gksarmy (author)trf2010-04-19

A good dovo razor introductory price is $99.99 :S
and i think im going to find a good picture of a razor online and cut it out, then spray paint that onto my piece of steel. then bench grind it down.

ajn142 (author)Gksarmy2010-08-07

Scrap steel from saw blades or files is best. It's high carbon and made for cutting and what not. You would probably be best off using a file, grinding off the teeth as otherwise they will hold dirt and rust and other things that will keep you from properly forging it, then heating it up and drawing it out (making it thinner). If it is going to be heated up between marking and grinding it, then you will have to use soapstone and not spraypaint. This should be availiable at any welding supply store, and you can probably find one where you buy your metal or at the local hardware store.

big trav (author)Gksarmy2010-06-12

Honestly I am a bladesmith and there is no way you will get it at the first attempt it is not just about the grinding or forging to shape there is hardening and tempering and honestly with a bench grinder and a dremel you will be pushing pooh up hill right from the start. You would be better off buying a good quality straight razor. Usually these are ICE hardened and are made in such a fashion that they work!!!

Gksarmy (author)big trav2010-06-14

good thing this site's not about trying to do stuff yourself or anything....

Dark Solar (author)Gksarmy2010-12-06

Be cautious--not all cat litters are created equal. I had a very bad experience with cat litter involving evolution of chlorine gas upon heating. For safety's sake, heat-test a small sample first.

JR57 (author)2015-07-07

Can a aluminum gas grill be used as long as heat coating(clay mix)is used inside?

Drennen (author)2015-01-04

my husband is trying to build a furnace out of a 55 gallon drum .its purpose is just to heat box steel enough to be able to twist it different ways . what do I need to do this and how thick should my layer of cement be? I believe they are going to cut it in half and use the one half as a lid. What do us suggest ? The pieces they are trying to heat are the are probably 3 feet long or better. Or should they leave the drum together what are your thoughts and where is the best and cheapest pla ce to buy the cement and what is it called exactly?

greenfreak (author)2011-05-12

hey, what might u be using to blow air into this thing?.... ive had many attempts at building a forge but none have worked because i cant get the right device! :/ and and all help will be thanked!

kingzilla (author)greenfreak2013-09-30

a hair dryer with a cold air setting works pretty decently.

harmsc12 (author)greenfreak2011-12-18

I've been reading up to build my own forge. Maybe you should look up clinkers.

Gator1070_ (author)greenfreak2011-09-10

i just used an old dirt devil vacume , it sucks from the front and "BLOWS" into the bag just rerig the bag to a hose and you got it......the olny thing is you really need a way to control the amount of air comming into the system, so what i did is got a dimmer switch , and a standerd plugin-outlet, hact up an extintion cord, and. the male end of the cord goes in the wall then, it goes into the outlet box through the dimmer switch and into the plugin.. now i have not built a forge yet still working on that, however i do use it as the air intake on my blast-furnace. works really well..!!!!!!!!!!

trf (author)greenfreak2011-05-24

Well optimally somethin with a good airflow. The BEST thing you can get is an old hand cranked blacksmiths blower. Other things that work are "squirrel cage" blowers. You may have seen one drying the floor to your local walmart at the enterance. Its round with a small outlet hole usually wide on the floor models. Other ideas i can think of are old ELECTRIC leaf blowers! Sorry for taking so long to respond!

pakman910 (author)2013-05-22

How much does this thing weigh now? Can you even lift it?

kage_no_mozaiku (author)2013-03-15

i'm very happy to run across this. i have an old gas grill out back which will negate me buying a feeder trough. thanks a lot for posting this.

jmoorm2 (author)2013-01-29

About how much did you have to use to fill your grill to this level?

zombskii (author)2012-12-31

Could i just use an old gas BBQ? (Without taking stuff out and using the gas parts) an would i still need a tuyere if this was do-able?

soldeir 9 (author)2012-07-23

is tthe tuyere really necesary?

blkhawk (author)soldeir 92012-11-18

Blowing air into the forge allows for the rise of the temperature in the forge in order to make the steel malleable. For more information read about the Bessemer process and the basic oxygen steelmaking

soldeir 9 (author)blkhawk2012-11-18

oooohkkk thx much appreciated, cheers bud

kpurse (author)2012-01-02

your link doesn't work

Daitallica (author)kpurse2012-03-01

think he means :

Shadow13! (author)2012-01-03

I know their would be more to disassemble, but could you do this with a broken gas grill instead of a charcoal one?

Truehart (author)Shadow13!2012-03-01

Step 1 "Clean the crap out" tells us to take out all the inards, i.e. racks, burners, etc. In other words, he used an old gas grill for this.

Mrcheese15 (author)2011-11-26

do you think this would work with a propane bbq?

skimmo (author)2011-05-17

could you use a 44 gallon drum

jetboy (author)2011-04-25

wouldn't ashes (fine and free of debris) work ive used it before, i mixed it with water and let it set and it hardened up nicely

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