Homemade Forge

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Introduction: Homemade Forge

Hey guys, today I bring you my step-by-step guide to building your own forge.
A while ago, I decided that I wanted to start doing some more serious metal-working and start in the art of manliness: blacksmithing. My only trouble was that I couldnt find many easy ways of building one, so I began planning and building for myself! Hope this helps anyone with the same predicament. 

Step 1: Your Materials

The size of your forge is completely up to you, however for my forge, the materials you will need are: 
58 cement or fire bricks, preferably with the dimensions along the lines of 12"x5"x5"
Steel grating that will be as wide and long as your forge
Air supply/bellows (I used a shop-vac in this case) 
Coal

Step 2: Laying Your Bricks

First thing you will want to do is to find a location to put your forge. Put it in an open space away from trees and cover so your smoke and carbon monoxide can escape easily.
Next, you will want to flatten the ground you wish to use for your forge. You could even get some extra bricks and use them as a foundation.
Finally, based on your plan, start laying your bricks down. For my particular forge, I wanted it to be a pretty decent size, so I laid them so that there were 2 full brick lengths on each side. 

Step 3: Incorporating Your Bellows

Keep stacking your bricks in a staggered formation so that the forge is stronger and less likely to collapse. Depending on how high you want your forge to stand will cause a variation on where you put your bellow opening. Originally I was not going to have mine as tall as it was, but I changed that.
Once you have reached the 5th layer of bricks, slide a brick over far enough to fit the nozzle of your vacuum in. You may cut the protruding part of the brick off for aesthetics, however I did not. 

Step 4: Adding Your Grate

This is probably the most straightforward step in this instructable. Place your steel grating on your 6th layer of bricks and continue to stack bricks on top of that, leaving the front open so you can insert your object to be forged. 

The steel grating is there so that as your coal burns down and gets smaller, the ash and useless remnants fall thru and are out of the way. The grating can be moved at a later time to clear the ash out. 

Step 5: Finishing Up

Well, to finish up, you can trim off and protruding ends and fill any gaps in the bricks. I would advise not the use mortar to hold the bricks together as it may crack or explode from the heat if it is not perfectly dried. Your next step is to throw on some coal and fire up your new forge. 
Get yourself some hammers, tongs, punches and chisels, an anvil and get to work.
Thanks for reading!

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    So I have everything ready to build the forge part of metalworking, but I'm having trouble finding a railroad i beam or cheap anvil. Can I use the anvil that comes on a bench vise?

    37 Comments

    hi. i know this is a rather old post but I want to ask somethings.

    I am 16 and starting my own forge, I have looked and cant find fire bricks. could I possibly use building bricks instead?

    1 reply

    If you want your forge to get hot enough to re forge steel, then you should use fire bricks. I just found some cheap ones at Lowes next to their red bricks. they were like 2.40 per brick. I was about to buy 6 bricks for 30 bucks before i found these. But if you are wanting to say..smelt aluminum, regular bricks should be safe enough.

    depending on the metal you are going to work with you are probably looking at at least 600 - 1200 deg C so personally I'd use a firebrick. I wouldn't recommend using a concrete block that's designed for construction at such extreme temperatures.

    I know that it has been a while since this has been posted but I have a question.

    In my town it is quite difficult to find firebrick; the best I can find are the bricks that are used to line the bottom of wood burning stoves or fireplaces. They are 4.5" x 9" x 1.25" in dimension. These bricks come in bundles of six and cost somewhere between 25 and 40 dollars.

    My question is; can I build the base of the forge out of concrete bricks and use a layer of firebricks for the fire box? Maybe even a double layer if necessary.

    Thanks,

    Damion.

    2 replies

    i burn wood as my main heat in house, so i dont see why not. just be careful they are known to crack over time because of the heat. i always change the brick every year due to such nature

    In fairness, the brick that I used here is not firebrick. I suggested that you should use that but can alternatively use cement bricks as I did in this build. Chances are your bricks are going to crack and need replaced anyway, so try not to use anything too expensive!

    can pacific clay brick be used as well?

    In addition to the above cement/concrete can and will explode under
    high heat. that is why we did not use portland cement when making the
    kilns

    Hi,

    I am an Aussie and owned a clay brick works. We built our own brick Kilns holding approximately 50,000 bricks. Our "mortar" was approximately half clay and sand. The clay we used was the same as we made our red bricks. Apart from design, which I wont go into here, the laying of the bricks consisted of "buttering" the brick with the mud/sand mix. "Buttering" literally was putting it on the bricks and then scraping it off leaving a thin layer. some thousands of bricks were laid end on end, basically because of the expansion and contraction we needed the weight, so I think this is your answer for mortaring. I will add a little more thought about mortar. In my young days, (I am 83) mortar for houses was lime and sand. Those homes stood for 100's of years. Today they add cement (portland cement) to the sand and sometimes lime to make them more water proof. However, for the inside of the fire place, it was/is still better to use the old lime/sand mortar. It would last as long as the house. the main damaged seemed to be from throwing logs into the fire and hitting the bricks. With the lime/sand mortar you could chisel out the mortar and replace the damaged bricks. When as a lad I often used the house fire to heat up a pice of stell I wanted to shape and the heat was more than adequate, so unless you want to melt the steel sand and clay make an adequate mortar. If you are worried about expansion and contraction then drive some steel posts at each side and tension them with fencing wire. Sorry for the lecture but I hope you found the information of interests. good smithing:)

    I've two questions, if anyone has time to answer. (I'm starting my own blacksmithing/bladesmithing voyage soon!):

    1) Is there any way to safely hold the bricks together? I ask since you said using mortar wouldn't work.

    2) Won't the steel grating melt as well? Or it doesn't melt since it's "beneath" the fire?

    Thank ye kindly!

    5 replies

    You can used a base plate or frame to hold your bricks, a V channel for long metal jobs works great, a pipe with hole drilled in it down along the bottom of the V for air. A brake drum or BBQ kettle base for a bowl shape and line with clay and ash where the heat sits. Standard cement mortar doesnt work.

    Use a heavier grate if you are concerned but they will all sag with heat, use 'fired' house brick with holes cast in them already instead of a grate and support those with a steel frame or tray.

    In terms of the bricks, I am not sure if there is a great way to hold everything together, but this has been around for a while and the bricks have all stayed in place and kept working well thus far!

    As for the steel grate, it will warp a little bit due to heat, but it hasn't had any issues so far. Because it is below the heat, and because you are not getting the metal hot enough to melt it as is, the grate shouldn't melt as long as you are using steel grating :)

    Alsey brand fire clay is my favorite,I gallon will lay 100 firebrick.You want to butter thin 1/8 inch.Use small fireplace trowel

    Wow, thank you for the swift response, Joshua!

    As for the grating, guess I'll just do a test run, and if it holds together fine, I'll keep an eye on it after every use. If it warps too much I'll just replace it.

    And the refractory mortar makes a lot of sense. Not sure how it is where you live, but it's largely used at my location for those big, orange brick barbecue furnaces.

    Many thanks, Master Joshua!

    Another commenter has suggested using refractory mortar to hold the bricks together tho. I haven't done this, so I can't personally speak to it's effectiveness. But I don't see why it wouldn't work :)

    With regards to using bricks for the structure. Firebricks are fine but expensive, 'fired' house bricks have been kiln fired and will withstand 1500C without temp issues but they will start to break down after a lot of use, fired soft clay bricks will breakdown after less use, unfired home made bricks from clay or mud will be fine they are porous and air will bleed out but they will have less mechanical strength. Concrete brick/pavers is not designed for heat stability and will break down over time.

    Fire brick clay or mortar is ideal for joining but you can get away with just stacking the bricks, unless you need a permanent structure, after all it is mainly just for containment of heat and fuel source.

    A simple way to make a portable forge is to just stack bricks and dismantle later.

    Ancient cultures just use ash, dirt or sand as the insulating material between your heat source and structure.

    DO NOT use river stones, they explode because the water has penetrated thru them and they take years to dry out properly - the internal water turns to steam and they explode because they are not usually porous.

    Would pavers be able to withstand the heat instead of fire bricks?

    2 replies

    Will not hold up long before cracking

    I'm not sure what you mean by "pavers".